From patchwork Mon Feb 5 16:34:05 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Donnefort X-Patchwork-Id: 196921 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7301:168b:b0:106:860b:bbdd with SMTP id ma11csp991073dyb; Mon, 5 Feb 2024 08:34:47 -0800 (PST) X-Google-Smtp-Source: AGHT+IHlRcqvnoSHpvLoVkz4GY7VniSlIqWu98A/5T+iE0lAY8S4vBymrNpZCiLH+9cDR6UwKJhh X-Received: by 2002:a17:90a:5aa2:b0:290:69e2:de18 with SMTP id n31-20020a17090a5aa200b0029069e2de18mr15141567pji.41.1707150887822; Mon, 05 Feb 2024 08:34:47 -0800 (PST) ARC-Seal: i=2; a=rsa-sha256; t=1707150887; cv=pass; d=google.com; s=arc-20160816; b=Ta3eKSQ9ObFCfTf1Bs0hD9PrSvAUucQ1iVRWRUPIsSodukXoPNtjh+ykzPff+HZcJz Iu0vEOFyhMSrfunhnK2i2iSwxRZtbp9Ro/lOeBgNge01Yt1/xxm5xZYyhJRoiKsIsM6j zB9plfpA6x2/dQ89rbq9JN4N4/AgK/iSRbKXGTJ0RdYE5lm0YFqm5R2p+pt5/3gj0fp8 Pw7uiVkeXGRVOi80oy9JQYCOVWEce0wbA7UyaJOpulGoWTbPhccOcvlNT7VP71v2YaqG +2Se8EIvbNS96eIql/LQS5Tq7mCSyFrX18v8PzkBWeAMBgeYBez8EZUAvsJlMLDfqH/R /LaA== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:from:subject:message-id:references:mime-version :list-unsubscribe:list-subscribe:list-id:precedence:in-reply-to:date :dkim-signature; bh=80zEqO4cAfaVKiES2NvcSNlY10tKCHIehQe+RxguKbw=; fh=gTEz/bl9oO0o7KKySqMpm2yop3crSEcn3mUZ7ICxBzA=; b=dlsx1SSrt+hI0uiREjQ/KufDYjkL6hJ5dW/02ErvOUpVen2Q9qij+p9ScGHS6kmO27 AJN6BTRhXQ31GljfMfaQEQH/sopdvUU9HY8aFKU/c6kcYKKPQzEvocEBz42vDwaa19IA N2TD4koG4eJVXU5QDqQYCPiX12lr/uhYZcQerPnpSq7/azjshgp30t4Bk9hTDo9ugDnX QjennzAzzAGSnjqRhoqlz+ai2eGmxkyjhs/8pSuTS+3AJ4MjpidQRpJDsoKItJiZYWmB Ir4WxKHUOY8L1RUEuqZ4QPSv4P8gL7PFTKcjxMvk6XM3sRcMoMkAqWD/1q2dtcj956Rr IF1g==; dara=google.com ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b="GkW9fd/V"; arc=pass (i=1 spf=pass spfdomain=flex--vdonnefort.bounces.google.com dkim=pass dkdomain=google.com dmarc=pass fromdomain=google.com); spf=pass (google.com: domain of linux-kernel+bounces-53015-ouuuleilei=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) smtp.mailfrom="linux-kernel+bounces-53015-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com X-Forwarded-Encrypted: i=1; AJvYcCXDmLnJarz+7BUhpwIUr3Cuz3qNmTjkrQ7rfvSekYHs8t52EnEn8/rCurs+5a2GuVhJIzpYRL4S9iArtcmo5S9j+aHpKA== Received: from sv.mirrors.kernel.org (sv.mirrors.kernel.org. [139.178.88.99]) by mx.google.com with ESMTPS id jh9-20020a170903328900b001d72907f487si88466plb.56.2024.02.05.08.34.47 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Feb 2024 08:34:47 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-53015-ouuuleilei=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b="GkW9fd/V"; arc=pass (i=1 spf=pass spfdomain=flex--vdonnefort.bounces.google.com dkim=pass dkdomain=google.com dmarc=pass fromdomain=google.com); spf=pass (google.com: domain of linux-kernel+bounces-53015-ouuuleilei=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) smtp.mailfrom="linux-kernel+bounces-53015-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sv.mirrors.kernel.org (Postfix) with ESMTPS id 7CBE2284F89 for ; Mon, 5 Feb 2024 16:34:47 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B898D3FE48; Mon, 5 Feb 2024 16:34:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="GkW9fd/V" Received: from mail-yw1-f202.google.com (mail-yw1-f202.google.com [209.85.128.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 801B42C191 for ; Mon, 5 Feb 2024 16:34:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707150862; cv=none; b=Pc04d49OTCiZNtp6kn/Rsi+fMphzDyqSgh7LRVLeCNfAqWq7otL14DBa5MYPgF8bq26q2v9jSj2EbGJxNrKmd7dLSwnhgcmgvZvRzWZzgLYlBnqA/ChMfL/m3PXxVjFfSIUpD2XX3l8CzG33DMXo38G5/iM7IugqnVNDm6jf/tU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707150862; c=relaxed/simple; bh=1fJD7FqdEtsCCOZb17HnRU5d9h5a6C+oEF9lp8cXViE=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Ubji0zUnDcd7oVERpJGIUYzKrYhWOkC6mGjKVWdJvZWWXl48+ErceMrtu88+//KywoWsvJcxIs2J6sBS2hQGGke3fDl29OXXIetWY1fu4YLedcQlhgJGLfhwM+ogyfOlLsaVBkAlxiqnmA29VEwM4FoL2roLFLnrerYd8yB+o8E= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=GkW9fd/V; arc=none smtp.client-ip=209.85.128.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Received: by mail-yw1-f202.google.com with SMTP id 00721157ae682-60444884b7dso24607947b3.1 for ; Mon, 05 Feb 2024 08:34:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1707150859; x=1707755659; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=80zEqO4cAfaVKiES2NvcSNlY10tKCHIehQe+RxguKbw=; b=GkW9fd/V6hxg852IQfJ1wDYoyBYECO+DM/8+k70qEs8E1EDe4c3kVTFiaC+V7IMFq8 h2IuN9gW1WJFKSpRBnX8b8Yd+pHqgO5XexOjsSuh6F0xr5IsQ3MguKBY9bkN9ypI73pm NBsCv8TWZqeJlN/oFhByC4aDI3y/4JbYK64PJbDuJPtHOzFU+ksWbx0ty2g1BnfUSGDm /cUK9TQNaLvVquo4Vfot2X085loqKBMLYNXfztmGmoY7rgO0lh13t5GQl1bjyJaUVB/A 58BNYWxswdfWtsf30cWNk3e+CCjGw8onB8TLJ8DDaMIpu70fmT8Jofab0dGp1M31BbjI L2Lw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707150859; x=1707755659; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=80zEqO4cAfaVKiES2NvcSNlY10tKCHIehQe+RxguKbw=; b=tdFuqMMYF17F03v5DwAl3TH7Hr48r17guMXJ4b7ab7r7g//faMRcM/tfEqvpEcLuIj HpjV8biDjdaxzp+pBjPjdkwBjHF3KMRZhGglrIispGO92QMQUTrd29ZItOSsxfDL/4Jr fQS7/eOrcezKbYYn9YVLAxdWlB9ACEPqBmztZHSyE7xULuhQNUNw16jIg9WqplEpl1AI N3vJ7x0UKHGSMoeSfsM6IUUlUnmXKgB17sOU/TrNN86gxxooqyzr9Wss9ObInWU/+ukU L3cbjAs5sjvMDOz+CsBsDA3ZDwc04xeXZSeJNT3U54iKpUTHe/VmuPnbDooAGwQPeknu zg5g== X-Gm-Message-State: AOJu0YxqXNXwf9FOKOHjbJW/4VH29Dluqoq/RwznppoHgCckqH4Nd26p CmUomEWeeSrnlC5aWXy2vPMQr7IrcLACmlURVs7+OyM89B2tWFB4jdSpLhm0VPNWCQb3/f99Flx hKjZWX74mfq5rKHA68w== X-Received: from vdonnefort.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:2eea]) (user=vdonnefort job=sendgmr) by 2002:a05:6902:138f:b0:dc6:dd74:de68 with SMTP id x15-20020a056902138f00b00dc6dd74de68mr457659ybu.12.1707150859536; Mon, 05 Feb 2024 08:34:19 -0800 (PST) Date: Mon, 5 Feb 2024 16:34:05 +0000 In-Reply-To: <20240205163410.2296552-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240205163410.2296552-1-vdonnefort@google.com> X-Mailer: git-send-email 2.43.0.594.gd9cf4e227d-goog Message-ID: <20240205163410.2296552-2-vdonnefort@google.com> Subject: [PATCH v14 1/6] ring-buffer: Zero ring-buffer sub-buffers From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: mathieu.desnoyers@efficios.com, kernel-team@android.com, Vincent Donnefort X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1790077449237174469 X-GMAIL-MSGID: 1790077449237174469 In preparation for the ring-buffer memory mapping where each subbuf will be accessible to user-space, zero all the page allocations. Signed-off-by: Vincent Donnefort Reviewed-by: Masami Hiramatsu (Google) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index fd4bfe3ecf01..ca796675c0a1 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1472,7 +1472,8 @@ static int __rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer, list_add(&bpage->list, pages); - page = alloc_pages_node(cpu_to_node(cpu_buffer->cpu), mflags, + page = alloc_pages_node(cpu_to_node(cpu_buffer->cpu), + mflags | __GFP_ZERO, cpu_buffer->buffer->subbuf_order); if (!page) goto free_pages; @@ -1557,7 +1558,8 @@ rb_allocate_cpu_buffer(struct trace_buffer *buffer, long nr_pages, int cpu) cpu_buffer->reader_page = bpage; - page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL, cpu_buffer->buffer->subbuf_order); + page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL | __GFP_ZERO, + cpu_buffer->buffer->subbuf_order); if (!page) goto fail_free_reader; bpage->page = page_address(page); @@ -5525,7 +5527,8 @@ ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu) if (bpage->data) goto out; - page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL | __GFP_NORETRY, + page = alloc_pages_node(cpu_to_node(cpu), + GFP_KERNEL | __GFP_NORETRY | __GFP_ZERO, cpu_buffer->buffer->subbuf_order); if (!page) { kfree(bpage); From patchwork Mon Feb 5 16:34:06 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Donnefort X-Patchwork-Id: 196924 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7301:168b:b0:106:860b:bbdd with SMTP id ma11csp991698dyb; Mon, 5 Feb 2024 08:35:54 -0800 (PST) X-Google-Smtp-Source: AGHT+IFk8PZT0IBhBH3q/XhNKMnNkfS6U1a2xGxo3TC+/3kBQPf4Eupcdw4rrdJoFI30iV8jNdnr X-Received: by 2002:a54:4389:0:b0:3be:a638:ee97 with SMTP id u9-20020a544389000000b003bea638ee97mr204334oiv.19.1707150954365; Mon, 05 Feb 2024 08:35:54 -0800 (PST) ARC-Seal: i=2; a=rsa-sha256; t=1707150954; cv=pass; d=google.com; s=arc-20160816; b=ufwvBf3YKejwjw0Em3nN+kJ0RCCBOZILRVd0/7hTJ41UVl/diZEVB4VzXuNgUqUtgj AujvMzI3n+JV99NLw9OjkIYHhJUNkbTthkz7g/S2aEjcls6u0suCvVeKpv/jnqUA2+2o iZ+wtvfTMelvY23yjcnX4BB5/7oc765q65y0c/nGGgz40CIBM2lRvaO456fORB6V5Txz RDg8FY2qKoLPbYtUkwnoAVK/rNMum+yVDby4/eDgRY1VeC5uFAUkxdYYKwkjZg/my63G HAPmLbadtvML71xLj45X0x1anCy+dPgY8n2URuVvWS/D4LfAjrtQnPylI1tagu08jALv c5XQ== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:from:subject:message-id:references:mime-version :list-unsubscribe:list-subscribe:list-id:precedence:in-reply-to:date :dkim-signature; bh=Dsrf45zfqob7KQL+G4oIjy+4WToDhiv7JskT8X1Un98=; fh=Ygqx7YqskEDFkV/IMMd2Us+VlLP5Zjm1rOM2DD19q7k=; b=hlgfhJwijIHoe6BlQK5GEZFVQARp/ToRVaXQRjcxppLx1T2UFQQqpdTLgCjMSrrfG/ j1PEVAJ9h718S4cq61LSNWFyzcJ8aIIGpdzDCzY9PvOFSV4esJS0cvgNfAZx4Rm07YBQ AytfAji1jvBBHNOGD8cO6WCOoCkt/kFMfwsFTzO9A9ijQbestgzG0qKzCy+1q3BQkP0L 1Pr0lSSzKnjZHSJcoF3aRaU8+LMFSHo8qOiiYInIblDtLgcPwDUcam/CzWC9fpSsQkYC Yq/FcVHClh6nUYg9Zswp6hwxTVcDnE7dj23TBRepRT/kJ1HV/SuF2lQMgos2MrzLPnXZ LdWA==; dara=google.com ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=j2OIkRLe; arc=pass (i=1 spf=pass spfdomain=flex--vdonnefort.bounces.google.com dkim=pass dkdomain=google.com dmarc=pass fromdomain=google.com); spf=pass (google.com: domain of linux-kernel+bounces-53017-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) smtp.mailfrom="linux-kernel+bounces-53017-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com X-Forwarded-Encrypted: i=1; AJvYcCXbuiX3AMseua7imjAvIVr/4ETxJ7b2UbZyYAJN7KL8nvgskK8FUTx+A3axkB3tHRBhwWV+Jmxwv0ZQBFWQPl4jlpQHBQ== Received: from ny.mirrors.kernel.org (ny.mirrors.kernel.org. [147.75.199.223]) by mx.google.com with ESMTPS id p10-20020a05620a112a00b00783de628217si189535qkk.121.2024.02.05.08.35.54 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Feb 2024 08:35:54 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-53017-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) client-ip=147.75.199.223; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=j2OIkRLe; arc=pass (i=1 spf=pass spfdomain=flex--vdonnefort.bounces.google.com dkim=pass dkdomain=google.com dmarc=pass fromdomain=google.com); spf=pass (google.com: domain of linux-kernel+bounces-53017-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) smtp.mailfrom="linux-kernel+bounces-53017-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ny.mirrors.kernel.org (Postfix) with ESMTPS id 4691F1C23928 for ; Mon, 5 Feb 2024 16:35:36 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 40BD645037; Mon, 5 Feb 2024 16:34:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="j2OIkRLe" Received: from mail-yw1-f201.google.com (mail-yw1-f201.google.com [209.85.128.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 062D93CF5F for ; Mon, 5 Feb 2024 16:34:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707150865; cv=none; b=K4iV0sf3cInVo9d1J4kv7XLpHajzylMs6MMds2XRq7UiBusUePrWBB6Ip3uI2XiEjHVji2oECgneDzHh4w6V0vv5baEJO6EqOMEA6S8/6II7KHhyqdD2q1/rMAH8d4hAGeoYKcAfAfmPtbuVHABOCbr3NxKqA/Depq/YqdwZXOU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707150865; c=relaxed/simple; bh=FCjvrSSzN1cRa6BR2+ach3IRO9kMTVzLT+cRCrJTX5c=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=FaaEYVCxRtzRx0ivC7LFZW+fOvXFGwIXgO3WqENyiyFwENzTe27GenqVosWzLIDuKBfDIq9Vz5a8gWT+UNMDGz4bnnMmWVJ7OgO9vXkbWAFX29EM2ITX5ZWs9jd7IiVTPlSFDfiH6nw/BP19ROBATZM497rWnosSZtfpL3IlsCs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=j2OIkRLe; arc=none smtp.client-ip=209.85.128.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Received: by mail-yw1-f201.google.com with SMTP id 00721157ae682-604186a5775so52882867b3.1 for ; Mon, 05 Feb 2024 08:34:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1707150862; x=1707755662; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=Dsrf45zfqob7KQL+G4oIjy+4WToDhiv7JskT8X1Un98=; b=j2OIkRLenzlLqYCe2A7w3f6Xjvn0XXH9fknnDFxcbPelgWZx1Sc9TIYihrkPBbMQOp EE2KESsqSUIzWp0+7bZ0LpqC/aRoLBYcy6Rrqtdoa9loABOuVekY2JynS4cqH+uZcN20 e2z40fLxv1CnxUEwnsrLLduTSiUkQog7RIdtXL2EcYCPEsVzsNILzOXfFIxStKf01Vz9 8t62hTmzyQtiIvnGF4zfGX1D5v7yzMiFBr3icJUttNhLWKgOCy+zfli9581ypVyPVkb+ SM1KYsOGhBiiclzD/fmvR2kijiYl+cWuEaH4L0lDR15IqVnQ81cgRPDsUsze7267bKhj YQJg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707150862; x=1707755662; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Dsrf45zfqob7KQL+G4oIjy+4WToDhiv7JskT8X1Un98=; b=gic+GSJm2K3kHQ/8vr4w0d7FR9+hslhwHTpzeSXdVZhM6xsZ2+A7eey0Xdaxh2DCx1 l/OH93yTR/w9iI8lwJVPRsVHDRQFEemPpJkBJppqCAiVzUSwXPEW0h76RAUtPYKbl3O2 dcP7OE29lq+ZsTIwGDckuS0k4fZRpqpAEUluRD33t9PxGJTT4x9rN8I8MaOa/B0MEIVu f/S9VXXrhK6qaZJrD6z5RFi77OTXyXBuKRRLrNipx54FLRhWZfhXUnL4K3Ly1D2XbcBv RhMGNWdex5ddItAJYqaV3fY+ZVNtz2djTNYCDzz3O63oRJlRYwgIdW9zcXndexTdNqmP +BBw== X-Gm-Message-State: AOJu0YxbiSS2wwI5ASayhkkkwHpXnTOFpZ8JGQmbbbq3R5FJvWfld2w9 Wsz2GP9ZvvUzdNmgeXWPG2ghWmbzdxYeJ8rQ8juS3lwqxT4CQCuc0U8KFgyI5QjXd/Hi3/9TqUb 7UWut94V6CakXIla8bg== X-Received: from vdonnefort.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:2eea]) (user=vdonnefort job=sendgmr) by 2002:a05:690c:d94:b0:5ff:6e82:ea31 with SMTP id da20-20020a05690c0d9400b005ff6e82ea31mr32192ywb.3.1707150862063; Mon, 05 Feb 2024 08:34:22 -0800 (PST) Date: Mon, 5 Feb 2024 16:34:06 +0000 In-Reply-To: <20240205163410.2296552-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240205163410.2296552-1-vdonnefort@google.com> X-Mailer: git-send-email 2.43.0.594.gd9cf4e227d-goog Message-ID: <20240205163410.2296552-3-vdonnefort@google.com> Subject: [PATCH v14 2/6] ring-buffer: Introducing ring-buffer mapping functions From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: mathieu.desnoyers@efficios.com, kernel-team@android.com, Vincent Donnefort X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1790077518820377455 X-GMAIL-MSGID: 1790077518820377455 In preparation for allowing the user-space to map a ring-buffer, add a set of mapping functions: ring_buffer_{map,unmap}() ring_buffer_map_fault() And controls on the ring-buffer: ring_buffer_map_get_reader() /* swap reader and head */ Mapping the ring-buffer also involves: A unique ID for each subbuf of the ring-buffer, currently they are only identified through their in-kernel VA. A meta-page, where are stored ring-buffer statistics and a description for the current reader The linear mapping exposes the meta-page, and each subbuf of the ring-buffer, ordered following their unique ID, assigned during the first mapping. Once mapped, no subbuf can get in or out of the ring-buffer: the buffer size will remain unmodified and the splice enabling functions will in reality simply memcpy the data instead of swapping subbufs. Signed-off-by: Vincent Donnefort diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index fa802db216f9..0841ba8bab14 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -6,6 +6,8 @@ #include #include +#include + struct trace_buffer; struct ring_buffer_iter; @@ -221,4 +223,9 @@ int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node); #define trace_rb_cpu_prepare NULL #endif +int ring_buffer_map(struct trace_buffer *buffer, int cpu); +int ring_buffer_unmap(struct trace_buffer *buffer, int cpu); +struct page *ring_buffer_map_fault(struct trace_buffer *buffer, int cpu, + unsigned long pgoff); +int ring_buffer_map_get_reader(struct trace_buffer *buffer, int cpu); #endif /* _LINUX_RING_BUFFER_H */ diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h new file mode 100644 index 000000000000..182e05a3004a --- /dev/null +++ b/include/uapi/linux/trace_mmap.h @@ -0,0 +1,46 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _TRACE_MMAP_H_ +#define _TRACE_MMAP_H_ + +#include + +/** + * struct trace_buffer_meta - Ring-buffer Meta-page description + * @meta_page_size: Size of this meta-page. + * @meta_struct_len: Size of this structure. + * @subbuf_size: Size of each sub-buffer. + * @nr_subbufs: Number of subbfs in the ring-buffer. + * @reader.lost_events: Number of events lost at the time of the reader swap. + * @reader.id: subbuf ID of the current reader. From 0 to @nr_subbufs - 1 + * @reader.read: Number of bytes read on the reader subbuf. + * @flags: Placeholder for now, no defined values. + * @entries: Number of entries in the ring-buffer. + * @overrun: Number of entries lost in the ring-buffer. + * @read: Number of entries that have been read. + * @Reserved1: Reserved for future use. + * @Reserved2: Reserved for future use. + */ +struct trace_buffer_meta { + __u32 meta_page_size; + __u32 meta_struct_len; + + __u32 subbuf_size; + __u32 nr_subbufs; + + struct { + __u64 lost_events; + __u32 id; + __u32 read; + } reader; + + __u64 flags; + + __u64 entries; + __u64 overrun; + __u64 read; + + __u64 Reserved1; + __u64 Reserved2; +}; + +#endif /* _TRACE_MMAP_H_ */ diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index ca796675c0a1..dcb4a0bc7ecb 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -338,6 +338,7 @@ struct buffer_page { local_t entries; /* entries on this page */ unsigned long real_end; /* real end of data */ unsigned order; /* order of the page */ + u32 id; /* ID for external mapping */ struct buffer_data_page *page; /* Actual data page */ }; @@ -484,6 +485,12 @@ struct ring_buffer_per_cpu { u64 read_stamp; /* pages removed since last reset */ unsigned long pages_removed; + + unsigned int mapped; + struct mutex mapping_lock; + unsigned long *subbuf_ids; /* ID to addr */ + struct trace_buffer_meta *meta_page; + /* ring buffer pages to update, > 0 to add, < 0 to remove */ long nr_pages_to_update; struct list_head new_pages; /* new pages to add */ @@ -1548,6 +1555,7 @@ rb_allocate_cpu_buffer(struct trace_buffer *buffer, long nr_pages, int cpu) init_irq_work(&cpu_buffer->irq_work.work, rb_wake_up_waiters); init_waitqueue_head(&cpu_buffer->irq_work.waiters); init_waitqueue_head(&cpu_buffer->irq_work.full_waiters); + mutex_init(&cpu_buffer->mapping_lock); bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()), GFP_KERNEL, cpu_to_node(cpu)); @@ -1738,8 +1746,6 @@ bool ring_buffer_time_stamp_abs(struct trace_buffer *buffer) return buffer->time_stamp_abs; } -static void rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer); - static inline unsigned long rb_page_entries(struct buffer_page *bpage) { return local_read(&bpage->entries) & RB_WRITE_MASK; @@ -5160,6 +5166,19 @@ static void rb_clear_buffer_page(struct buffer_page *page) page->read = 0; } +static void rb_update_meta_page(struct ring_buffer_per_cpu *cpu_buffer) +{ + struct trace_buffer_meta *meta = cpu_buffer->meta_page; + + WRITE_ONCE(meta->reader.read, cpu_buffer->reader_page->read); + WRITE_ONCE(meta->reader.id, cpu_buffer->reader_page->id); + WRITE_ONCE(meta->reader.lost_events, cpu_buffer->lost_events); + + WRITE_ONCE(meta->entries, local_read(&cpu_buffer->entries)); + WRITE_ONCE(meta->overrun, local_read(&cpu_buffer->overrun)); + WRITE_ONCE(meta->read, cpu_buffer->read); +} + static void rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer) { @@ -5204,6 +5223,9 @@ rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer) cpu_buffer->lost_events = 0; cpu_buffer->last_overrun = 0; + if (READ_ONCE(cpu_buffer->mapped)) + rb_update_meta_page(cpu_buffer); + rb_head_page_activate(cpu_buffer); cpu_buffer->pages_removed = 0; } @@ -5418,6 +5440,12 @@ int ring_buffer_swap_cpu(struct trace_buffer *buffer_a, cpu_buffer_a = buffer_a->buffers[cpu]; cpu_buffer_b = buffer_b->buffers[cpu]; + /* It's up to the callers to not try to swap mapped buffers */ + if (WARN_ON_ONCE(cpu_buffer_a->mapped || cpu_buffer_b->mapped)) { + ret = -EBUSY; + goto out; + } + /* At least make sure the two buffers are somewhat the same */ if (cpu_buffer_a->nr_pages != cpu_buffer_b->nr_pages) goto out; @@ -5682,7 +5710,8 @@ int ring_buffer_read_page(struct trace_buffer *buffer, * Otherwise, we can simply swap the page with the one passed in. */ if (read || (len < (commit - read)) || - cpu_buffer->reader_page == cpu_buffer->commit_page) { + cpu_buffer->reader_page == cpu_buffer->commit_page || + READ_ONCE(cpu_buffer->mapped)) { struct buffer_data_page *rpage = cpu_buffer->reader_page->page; unsigned int rpos = read; unsigned int pos = 0; @@ -5901,6 +5930,11 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) cpu_buffer = buffer->buffers[cpu]; + if (READ_ONCE(cpu_buffer->mapped)) { + err = -EBUSY; + goto error; + } + /* Update the number of pages to match the new size */ nr_pages = old_size * buffer->buffers[cpu]->nr_pages; nr_pages = DIV_ROUND_UP(nr_pages, buffer->subbuf_size); @@ -6002,6 +6036,301 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) } EXPORT_SYMBOL_GPL(ring_buffer_subbuf_order_set); +#define subbuf_page(off, start) \ + virt_to_page((void *)(start + (off << PAGE_SHIFT))) + +#define foreach_subbuf_page(sub_order, start, page) \ + page = subbuf_page(0, (start)); \ + for (int __off = 0; __off < (1 << (sub_order)); \ + __off++, page = subbuf_page(__off, (start))) + +static inline void subbuf_map_prepare(unsigned long subbuf_start, int order) +{ + struct page *page; + + /* + * When allocating order > 0 pages, only the first struct page has a + * refcount > 1. Increasing the refcount here ensures none of the struct + * page composing the sub-buffer is freeed when the mapping is closed. + */ + foreach_subbuf_page(order, subbuf_start, page) + page_ref_inc(page); +} + +static inline void subbuf_unmap(unsigned long subbuf_start, int order) +{ + struct page *page; + + foreach_subbuf_page(order, subbuf_start, page) { + page_ref_dec(page); + page->mapping = NULL; + } +} + +static void rb_free_subbuf_ids(struct ring_buffer_per_cpu *cpu_buffer) +{ + int sub_id; + + for (sub_id = 0; sub_id < cpu_buffer->nr_pages + 1; sub_id++) + subbuf_unmap(cpu_buffer->subbuf_ids[sub_id], + cpu_buffer->buffer->subbuf_order); + + kfree(cpu_buffer->subbuf_ids); + cpu_buffer->subbuf_ids = NULL; +} + +static int rb_alloc_meta_page(struct ring_buffer_per_cpu *cpu_buffer) +{ + if (cpu_buffer->meta_page) + return 0; + + cpu_buffer->meta_page = page_to_virt(alloc_page(GFP_USER | __GFP_ZERO)); + if (!cpu_buffer->meta_page) + return -ENOMEM; + + return 0; +} + +static void rb_free_meta_page(struct ring_buffer_per_cpu *cpu_buffer) +{ + unsigned long addr = (unsigned long)cpu_buffer->meta_page; + + virt_to_page((void *)addr)->mapping = NULL; + free_page(addr); + cpu_buffer->meta_page = NULL; +} + +static void rb_setup_ids_meta_page(struct ring_buffer_per_cpu *cpu_buffer, + unsigned long *subbuf_ids) +{ + struct trace_buffer_meta *meta = cpu_buffer->meta_page; + unsigned int nr_subbufs = cpu_buffer->nr_pages + 1; + struct buffer_page *first_subbuf, *subbuf; + int id = 0; + + subbuf_ids[id] = (unsigned long)cpu_buffer->reader_page->page; + subbuf_map_prepare(subbuf_ids[id], cpu_buffer->buffer->subbuf_order); + cpu_buffer->reader_page->id = id++; + + first_subbuf = subbuf = rb_set_head_page(cpu_buffer); + do { + if (id >= nr_subbufs) { + WARN_ON(1); + break; + } + + subbuf_ids[id] = (unsigned long)subbuf->page; + subbuf->id = id; + subbuf_map_prepare(subbuf_ids[id], cpu_buffer->buffer->subbuf_order); + + rb_inc_page(&subbuf); + id++; + } while (subbuf != first_subbuf); + + /* install subbuf ID to kern VA translation */ + cpu_buffer->subbuf_ids = subbuf_ids; + + meta->meta_page_size = PAGE_SIZE; + meta->meta_struct_len = sizeof(*meta); + meta->nr_subbufs = nr_subbufs; + meta->subbuf_size = cpu_buffer->buffer->subbuf_size + BUF_PAGE_HDR_SIZE; + + rb_update_meta_page(cpu_buffer); +} + +static inline struct ring_buffer_per_cpu * +rb_get_mapped_buffer(struct trace_buffer *buffer, int cpu) +{ + struct ring_buffer_per_cpu *cpu_buffer; + + if (!cpumask_test_cpu(cpu, buffer->cpumask)) + return ERR_PTR(-EINVAL); + + cpu_buffer = buffer->buffers[cpu]; + + mutex_lock(&cpu_buffer->mapping_lock); + + if (!cpu_buffer->mapped) { + mutex_unlock(&cpu_buffer->mapping_lock); + return ERR_PTR(-ENODEV); + } + + return cpu_buffer; +} + +static inline void rb_put_mapped_buffer(struct ring_buffer_per_cpu *cpu_buffer) +{ + mutex_unlock(&cpu_buffer->mapping_lock); +} + +int ring_buffer_map(struct trace_buffer *buffer, int cpu) +{ + struct ring_buffer_per_cpu *cpu_buffer; + unsigned long flags, *subbuf_ids; + int err = 0; + + if (!cpumask_test_cpu(cpu, buffer->cpumask)) + return -EINVAL; + + cpu_buffer = buffer->buffers[cpu]; + + mutex_lock(&cpu_buffer->mapping_lock); + + if (cpu_buffer->mapped) { + if (cpu_buffer->mapped == UINT_MAX) + err = -EBUSY; + else + WRITE_ONCE(cpu_buffer->mapped, cpu_buffer->mapped + 1); + mutex_unlock(&cpu_buffer->mapping_lock); + return err; + } + + /* prevent another thread from changing buffer/sub-buffer sizes */ + mutex_lock(&buffer->mutex); + + err = rb_alloc_meta_page(cpu_buffer); + if (err) + goto unlock; + + /* subbuf_ids include the reader while nr_pages does not */ + subbuf_ids = kzalloc(sizeof(*subbuf_ids) * (cpu_buffer->nr_pages + 1), + GFP_KERNEL); + if (!subbuf_ids) { + rb_free_meta_page(cpu_buffer); + err = -ENOMEM; + goto unlock; + } + + atomic_inc(&cpu_buffer->resize_disabled); + + /* + * Lock all readers to block any subbuf swap until the subbuf IDs are + * assigned. + */ + raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags); + + rb_setup_ids_meta_page(cpu_buffer, subbuf_ids); + cpu_buffer->mapped = 1; + + raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); +unlock: + mutex_unlock(&buffer->mutex); + mutex_unlock(&cpu_buffer->mapping_lock); + + return err; +} + +int ring_buffer_unmap(struct trace_buffer *buffer, int cpu) +{ + struct ring_buffer_per_cpu *cpu_buffer; + unsigned long flags; + int err = 0; + + if (!cpumask_test_cpu(cpu, buffer->cpumask)) + return -EINVAL; + + cpu_buffer = buffer->buffers[cpu]; + + mutex_lock(&cpu_buffer->mapping_lock); + + if (!cpu_buffer->mapped) { + err = -ENODEV; + goto out; + } else if (cpu_buffer->mapped > 1) { + WRITE_ONCE(cpu_buffer->mapped, cpu_buffer->mapped - 1); + goto out; + } + + mutex_lock(&buffer->mutex); + raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags); + + cpu_buffer->mapped = 0; + + raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); + + rb_free_subbuf_ids(cpu_buffer); + rb_free_meta_page(cpu_buffer); + atomic_dec(&cpu_buffer->resize_disabled); + + mutex_unlock(&buffer->mutex); +out: + mutex_unlock(&cpu_buffer->mapping_lock); + + return err; +} + +/* + * +--------------+ pgoff == 0 + * | meta page | + * +--------------+ pgoff == 1 + * | subbuffer 0 | + * +--------------+ pgoff == 1 + (1 << subbuf_order) + * | subbuffer 1 | + * ... + */ +struct page *ring_buffer_map_fault(struct trace_buffer *buffer, int cpu, + unsigned long pgoff) +{ + struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu]; + unsigned long subbuf_id, subbuf_offset, addr; + struct page *page; + + if (!pgoff) + return virt_to_page((void *)cpu_buffer->meta_page); + + pgoff--; + + subbuf_id = pgoff >> buffer->subbuf_order; + if (subbuf_id > cpu_buffer->nr_pages) + return NULL; + + subbuf_offset = pgoff & ((1UL << buffer->subbuf_order) - 1); + addr = cpu_buffer->subbuf_ids[subbuf_id] + (subbuf_offset * PAGE_SIZE); + page = virt_to_page((void *)addr); + + return page; +} + +int ring_buffer_map_get_reader(struct trace_buffer *buffer, int cpu) +{ + struct ring_buffer_per_cpu *cpu_buffer; + unsigned long reader_size; + unsigned long flags; + + cpu_buffer = rb_get_mapped_buffer(buffer, cpu); + if (IS_ERR(cpu_buffer)) + return (int)PTR_ERR(cpu_buffer); + + raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags); +consume: + if (rb_per_cpu_empty(cpu_buffer)) + goto out; + + reader_size = rb_page_size(cpu_buffer->reader_page); + + /* + * There are data to be read on the current reader page, we can + * return to the caller. But before that, we assume the latter will read + * everything. Let's update the kernel reader accordingly. + */ + if (cpu_buffer->reader_page->read < reader_size) { + while (cpu_buffer->reader_page->read < reader_size) + rb_advance_reader(cpu_buffer); + goto out; + } + + if (WARN_ON(!rb_get_reader_page(cpu_buffer))) + goto out; + + goto consume; +out: + rb_update_meta_page(cpu_buffer); + raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); + rb_put_mapped_buffer(cpu_buffer); + + return 0; +} + /* * We only allocate new buffers, never free them if the CPU goes down. * If we were to free the buffer, then the user would lose any trace that was in From patchwork Mon Feb 5 16:34:07 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Donnefort X-Patchwork-Id: 196923 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7301:168b:b0:106:860b:bbdd with SMTP id ma11csp991566dyb; Mon, 5 Feb 2024 08:35:40 -0800 (PST) X-Google-Smtp-Source: AGHT+IHx5tXSlssHsnyQCDbwdPli8OINcfhaIHhZp2BUpAIuec/I8/rFuenM3IH2dYfc3rv30/mG X-Received: by 2002:aa7:d497:0:b0:55f:6b8:b2fb with SMTP id b23-20020aa7d497000000b0055f06b8b2fbmr5393403edr.1.1707150940406; Mon, 05 Feb 2024 08:35:40 -0800 (PST) ARC-Seal: i=2; a=rsa-sha256; t=1707150940; cv=pass; d=google.com; s=arc-20160816; b=l4IMKmPuZulIFCR+H8vqOzxHRmWcGIfhN9DuN0wOMTV5CpIgntD34mr4HEHf6/FEmb zvy1RhE3zsR93nLBSu3hPCvZmySr0FVDtYLeOrsBOdTC7t4qnbushgwiSfze9rZaGVTx Zhy52g4QRXvjPXFgHCFOZ8W99FjYg3QD6FMA53QH5YkokBejJtvGX+Iw6u9KvrMxDTg3 mMrsxOAxxBAK/SGZKruhM0bRn5xkMXi+VgrS+x17s8pRkT1FQX9SjrV5jNVThBLQkc0o jLMP1jMX8uUZy2ShDsnWC2XPql9rTLzcMa0bOUGB3itxefonwWTpFZ0VowWMQIeZLops IW5g== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:from:subject:message-id:references:mime-version :list-unsubscribe:list-subscribe:list-id:precedence:in-reply-to:date :dkim-signature; bh=H5XAz0EYa4xfVv/JB+sR3XxZL6LRYzXRUIrx6M/xkec=; fh=GkaL+SmIeHUwkm0+y3QCUBBPvymPZfQ/SI/J6FOqmGI=; b=O/ymj7xguvTMDHR1XACiXQ+v1G1EmvEbCX0/Qz2sx0d5e10XliuBAab7TS8sBM1/WN JM4wh/xywQDn4Hg94EybMR3uvxahup7t9TUpiVvsZyDvqd3hROskI5mU38IE2wod/Q16 +0iQ0XqRHK6Be4EG0EpJimlfg5XXP11OQDFR33wSu7/Io/tGRS7MDcKaPzGtH/ztqsVX rwEmICvs08p7++j2netSmCOQiNPTdiJfUNUjK4vcRBWHsb+/MFcx3U6nzbOtx5M/bckw PWWrJU3zOE/CjRSnfC6nFykwvr7MbPZmKKanrkBWZuo4/PHGMv/9+8UxZjuKWv0qnlMn QUrQ==; dara=google.com ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=SorJDpzR; arc=pass (i=1 spf=pass spfdomain=flex--vdonnefort.bounces.google.com dkim=pass dkdomain=google.com dmarc=pass fromdomain=google.com); spf=pass (google.com: domain of linux-kernel+bounces-53018-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) smtp.mailfrom="linux-kernel+bounces-53018-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com X-Forwarded-Encrypted: i=1; AJvYcCXf2F5zwSbdmeXqKT/nsfY+cmAl3F1GiD4ezpyksfs3YLYC8S+FhJOAWWejN/Bv4NwC3KrDg3lrRo7D5D/zsBi/7g+EBg== Received: from am.mirrors.kernel.org (am.mirrors.kernel.org. [2604:1380:4601:e00::3]) by mx.google.com with ESMTPS id dm15-20020a05640222cf00b00560122c3783si54371edb.90.2024.02.05.08.35.40 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Feb 2024 08:35:40 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-53018-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=SorJDpzR; arc=pass (i=1 spf=pass spfdomain=flex--vdonnefort.bounces.google.com dkim=pass dkdomain=google.com dmarc=pass fromdomain=google.com); spf=pass (google.com: domain of linux-kernel+bounces-53018-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) smtp.mailfrom="linux-kernel+bounces-53018-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by am.mirrors.kernel.org (Postfix) with ESMTPS id D2FA41F23B03 for ; Mon, 5 Feb 2024 16:35:39 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 9FBEB45036; Mon, 5 Feb 2024 16:34:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="SorJDpzR" Received: from mail-yw1-f201.google.com (mail-yw1-f201.google.com [209.85.128.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3DC1E405EB for ; Mon, 5 Feb 2024 16:34:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707150867; cv=none; b=B8uSKzeE6T+3D1r9mXJmwn7gYUTdfGGlUMvzJUlaeykOdigyrhzcqCuJWzZOTk+1vszLYtkKs5JejcSdn8f43BrprEtfsEjY01WW7vA5flL/ZjlHzXW/GeHenb/8zjDUFzh6ii5fZpzcYpMVaWroQ5C1/dT6boHm5d/iXAoByBo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707150867; c=relaxed/simple; bh=QvdTUhLXY1dbOrkxkIXt/yC9dno0L96QHACv8XnZPSw=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=clZjnMhkTuKqzUVQLG5pKzV3NsApOsCPGWzcAaS/lUmY7AkBRqxVn4sf6LSLAO+/gxayPids0+CTaVjXBxA6CBUB6oRGmbHRWuYe32l5TEiNNK9u3pQj5CwHpR9/G5oGraTTqxyV++4f/aw5G0N4DTRVsjTm3Ln1Fz24gfjTEog= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=SorJDpzR; arc=none smtp.client-ip=209.85.128.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Received: by mail-yw1-f201.google.com with SMTP id 00721157ae682-6040597d005so86313207b3.2 for ; Mon, 05 Feb 2024 08:34:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1707150864; x=1707755664; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=H5XAz0EYa4xfVv/JB+sR3XxZL6LRYzXRUIrx6M/xkec=; b=SorJDpzR3l8IgjR/u2isnGtS1nNlX6e5byY0XE/EUSv16iI7CkvajS3uq+fJBOSVAm HPkpkVbAmw9DTMIlQgwS1LH5ryVAl/eO50mCnrICuVL6UBsxdfrPrWIbYP86pEAaQGra 6qYrYZX0tKStboZ5defqt7ibFAWA3c13diQ4xy4FMLLOoK9YhSgKdj9mV5IT2fp1mxLy BLkQ2aqvi/Wv8+C9pgQqhIz8izDKEXh5yp1hLyfCXt0WOhvK1HJbunGgJ8eNA1IyLzG1 dZbmrMK5Mr4PEOQfEAa7ylMWeDHoRNJYs/QIBrjtEAVtwAFW2SEYKrxTSqOWIUpq20YI 2aMg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707150864; x=1707755664; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=H5XAz0EYa4xfVv/JB+sR3XxZL6LRYzXRUIrx6M/xkec=; b=eNkWAeepoC+cUKGqOjz/OBz5hj+rZNmCyEQP2I9/a1XlVn88Ne2d1bpGB+7KkgjzT7 7NHC/HiclHzLXJ904P3KFFaMK1eiICHslwaJwQ7TatjLATqlMptkA8hjIAXjX5RxTXyb BgyPcBPtzd+oTJtmLWZv8Faua0Yny/2H8fD2IoylD1bc1bZ3AOAcf+Uu0iwlxKNDb00P zeTsQ22lSQBy6F48kZzLlPz7lKd7nC62itoUuebcSCCSt+tQrBZcWEH1DMyGWYt8qCcc pu3WtrDCjUJaT4UChkU99+bumz5nuO3anFYKCYqo4wITF1azRm8B3QlF0/84D1SlW6TJ Mfjg== X-Gm-Message-State: AOJu0YwzGtQ85uIJT3EeXmkdvrDwlxHtfhkByVe7unJzhRPr0yvaSOcb 2bpztNYCAZJjJ+2TcYfI2O6lFSLAjubbiVedZMRx93lWMSWThihMe5noRF03o7rz/mtEO6fQOyq Qlauzjyl1MsGZwIX1wg== X-Received: from vdonnefort.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:2eea]) (user=vdonnefort job=sendgmr) by 2002:a81:9ad5:0:b0:5de:9c9f:3ee4 with SMTP id r204-20020a819ad5000000b005de9c9f3ee4mr6432ywg.6.1707150864356; Mon, 05 Feb 2024 08:34:24 -0800 (PST) Date: Mon, 5 Feb 2024 16:34:07 +0000 In-Reply-To: <20240205163410.2296552-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240205163410.2296552-1-vdonnefort@google.com> X-Mailer: git-send-email 2.43.0.594.gd9cf4e227d-goog Message-ID: <20240205163410.2296552-4-vdonnefort@google.com> Subject: [PATCH v14 3/6] tracing: Add snapshot refcount From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: mathieu.desnoyers@efficios.com, kernel-team@android.com, Vincent Donnefort X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1790077504435359637 X-GMAIL-MSGID: 1790077504435359637 When a ring-buffer is memory mapped by user-space, no trace or ring-buffer swap is possible. This means the snapshot feature is mutually exclusive with the memory mapping. Having a refcount on snapshot users will help to know if a mapping is possible or not. Instead of relying on the global trace_types_lock, a new spinlock is introduced to serialize accesses to trace_array->snapshot. This intends to allow access to that variable in a context where the mmap lock is already held. Signed-off-by: Vincent Donnefort diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 2a7c6fd934e9..4ebf4d0bd14c 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1300,6 +1300,50 @@ static void free_snapshot(struct trace_array *tr) tr->allocated_snapshot = false; } +static int tracing_arm_snapshot_locked(struct trace_array *tr) +{ + int ret; + + lockdep_assert_held(&trace_types_lock); + + spin_lock(&tr->snapshot_trigger_lock); + if (tr->snapshot == UINT_MAX) { + spin_unlock(&tr->snapshot_trigger_lock); + return -EBUSY; + } + + tr->snapshot++; + spin_unlock(&tr->snapshot_trigger_lock); + + ret = tracing_alloc_snapshot_instance(tr); + if (ret) { + spin_lock(&tr->snapshot_trigger_lock); + tr->snapshot--; + spin_unlock(&tr->snapshot_trigger_lock); + } + + return ret; +} + +int tracing_arm_snapshot(struct trace_array *tr) +{ + int ret; + + mutex_lock(&trace_types_lock); + ret = tracing_arm_snapshot_locked(tr); + mutex_unlock(&trace_types_lock); + + return ret; +} + +void tracing_disarm_snapshot(struct trace_array *tr) +{ + spin_lock(&tr->snapshot_trigger_lock); + if (!WARN_ON(!tr->snapshot)) + tr->snapshot--; + spin_unlock(&tr->snapshot_trigger_lock); +} + /** * tracing_alloc_snapshot - allocate snapshot buffer. * @@ -1373,10 +1417,6 @@ int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, mutex_lock(&trace_types_lock); - ret = tracing_alloc_snapshot_instance(tr); - if (ret) - goto fail_unlock; - if (tr->current_trace->use_max_tr) { ret = -EBUSY; goto fail_unlock; @@ -1395,6 +1435,10 @@ int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, goto fail_unlock; } + ret = tracing_arm_snapshot_locked(tr); + if (ret) + goto fail_unlock; + local_irq_disable(); arch_spin_lock(&tr->max_lock); tr->cond_snapshot = cond_snapshot; @@ -1439,6 +1483,8 @@ int tracing_snapshot_cond_disable(struct trace_array *tr) arch_spin_unlock(&tr->max_lock); local_irq_enable(); + tracing_disarm_snapshot(tr); + return ret; } EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable); @@ -1481,6 +1527,7 @@ int tracing_snapshot_cond_disable(struct trace_array *tr) } EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable); #define free_snapshot(tr) do { } while (0) +#define tracing_arm_snapshot_locked(tr) ({ -EBUSY; }) #endif /* CONFIG_TRACER_SNAPSHOT */ void tracer_tracing_off(struct trace_array *tr) @@ -6593,11 +6640,12 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) */ synchronize_rcu(); free_snapshot(tr); + tracing_disarm_snapshot(tr); } - if (t->use_max_tr && !tr->allocated_snapshot) { - ret = tracing_alloc_snapshot_instance(tr); - if (ret < 0) + if (t->use_max_tr) { + ret = tracing_arm_snapshot_locked(tr); + if (ret) goto out; } #else @@ -6606,8 +6654,13 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) if (t->init) { ret = tracer_init(t, tr); - if (ret) + if (ret) { +#ifdef CONFIG_TRACER_MAX_TRACE + if (t->use_max_tr) + tracing_disarm_snapshot(tr); +#endif goto out; + } } tr->current_trace = t; @@ -7709,10 +7762,11 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt, if (tr->allocated_snapshot) ret = resize_buffer_duplicate_size(&tr->max_buffer, &tr->array_buffer, iter->cpu_file); - else - ret = tracing_alloc_snapshot_instance(tr); - if (ret < 0) + + ret = tracing_arm_snapshot_locked(tr); + if (ret) break; + /* Now, we're going to swap */ if (iter->cpu_file == RING_BUFFER_ALL_CPUS) { local_irq_disable(); @@ -7722,6 +7776,7 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt, smp_call_function_single(iter->cpu_file, tracing_swap_cpu_buffer, (void *)tr, 1); } + tracing_disarm_snapshot(tr); break; default: if (tr->allocated_snapshot) { @@ -8846,8 +8901,13 @@ ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash, ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops; - if (glob[0] == '!') - return unregister_ftrace_function_probe_func(glob+1, tr, ops); + if (glob[0] == '!') { + ret = unregister_ftrace_function_probe_func(glob+1, tr, ops); + if (!ret) + tracing_disarm_snapshot(tr); + + return ret; + } if (!param) goto out_reg; @@ -8866,12 +8926,13 @@ ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash, return ret; out_reg: - ret = tracing_alloc_snapshot_instance(tr); + ret = tracing_arm_snapshot(tr); if (ret < 0) goto out; ret = register_ftrace_function_probe(glob, tr, ops, count); - + if (ret < 0) + tracing_disarm_snapshot(tr); out: return ret < 0 ? ret : 0; } @@ -9678,7 +9739,9 @@ trace_array_create_systems(const char *name, const char *systems) raw_spin_lock_init(&tr->start_lock); tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; - +#ifdef CONFIG_TRCER_MAX_TRACE + spinlock_init(&tr->snapshot_trigger_lock); +#endif tr->current_trace = &nop_trace; INIT_LIST_HEAD(&tr->systems); @@ -10648,7 +10711,9 @@ __init static int tracer_alloc_buffers(void) global_trace.current_trace = &nop_trace; global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; - +#ifdef CONFIG_TRACER_MAX_TRACE + spin_lock_init(&global_trace.snapshot_trigger_lock); +#endif ftrace_init_global_array_ops(&global_trace); init_trace_flags_index(&global_trace); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 00f873910c5d..bd312e9afe25 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -334,8 +334,8 @@ struct trace_array { */ struct array_buffer max_buffer; bool allocated_snapshot; -#endif -#ifdef CONFIG_TRACER_MAX_TRACE + spinlock_t snapshot_trigger_lock; + unsigned int snapshot; unsigned long max_latency; #ifdef CONFIG_FSNOTIFY struct dentry *d_max_latency; @@ -1973,12 +1973,16 @@ static inline void trace_event_eval_update(struct trace_eval_map **map, int len) #ifdef CONFIG_TRACER_SNAPSHOT void tracing_snapshot_instance(struct trace_array *tr); int tracing_alloc_snapshot_instance(struct trace_array *tr); +int tracing_arm_snapshot(struct trace_array *tr); +void tracing_disarm_snapshot(struct trace_array *tr); #else static inline void tracing_snapshot_instance(struct trace_array *tr) { } static inline int tracing_alloc_snapshot_instance(struct trace_array *tr) { return 0; } +static inline int tracing_arm_snapshot(struct trace_array *tr) { return 0; } +static inline void tracing_disarm_snapshot(struct trace_array *tr) { } #endif #ifdef CONFIG_PREEMPT_TRACER diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index b33c3861fbbb..62e4f58b8671 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -597,20 +597,12 @@ static int register_trigger(char *glob, return ret; } -/** - * unregister_trigger - Generic event_command @unreg implementation - * @glob: The raw string used to register the trigger - * @test: Trigger-specific data used to find the trigger to remove - * @file: The trace_event_file associated with the event - * - * Common implementation for event trigger unregistration. - * - * Usually used directly as the @unreg method in event command - * implementations. +/* + * True if the trigger was found and unregistered, else false. */ -static void unregister_trigger(char *glob, - struct event_trigger_data *test, - struct trace_event_file *file) +static bool try_unregister_trigger(char *glob, + struct event_trigger_data *test, + struct trace_event_file *file) { struct event_trigger_data *data = NULL, *iter; @@ -626,8 +618,32 @@ static void unregister_trigger(char *glob, } } - if (data && data->ops->free) - data->ops->free(data); + if (data) { + if (data->ops->free) + data->ops->free(data); + + return true; + } + + return false; +} + +/** + * unregister_trigger - Generic event_command @unreg implementation + * @glob: The raw string used to register the trigger + * @test: Trigger-specific data used to find the trigger to remove + * @file: The trace_event_file associated with the event + * + * Common implementation for event trigger unregistration. + * + * Usually used directly as the @unreg method in event command + * implementations. + */ +static void unregister_trigger(char *glob, + struct event_trigger_data *test, + struct trace_event_file *file) +{ + try_unregister_trigger(glob, test, file); } /* @@ -1470,7 +1486,7 @@ register_snapshot_trigger(char *glob, struct event_trigger_data *data, struct trace_event_file *file) { - int ret = tracing_alloc_snapshot_instance(file->tr); + int ret = tracing_arm_snapshot(file->tr); if (ret < 0) return ret; @@ -1478,6 +1494,14 @@ register_snapshot_trigger(char *glob, return register_trigger(glob, data, file); } +static void unregister_snapshot_trigger(char *glob, + struct event_trigger_data *data, + struct trace_event_file *file) +{ + if (try_unregister_trigger(glob, data, file)) + tracing_disarm_snapshot(file->tr); +} + static int snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data) { @@ -1510,7 +1534,7 @@ static struct event_command trigger_snapshot_cmd = { .trigger_type = ETT_SNAPSHOT, .parse = event_trigger_parse, .reg = register_snapshot_trigger, - .unreg = unregister_trigger, + .unreg = unregister_snapshot_trigger, .get_trigger_ops = snapshot_get_trigger_ops, .set_filter = set_trigger_filter, }; From patchwork Mon Feb 5 16:34:08 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Donnefort X-Patchwork-Id: 196925 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7301:168b:b0:106:860b:bbdd with SMTP id ma11csp991741dyb; Mon, 5 Feb 2024 08:35:56 -0800 (PST) X-Google-Smtp-Source: AGHT+IFnTmtNw7Zkd18SK5yUV6/paJTDSKIENFkNrJ2HwyOjl/1cl9Q4jEuQVxI2XPVUOk2wB8Ux X-Received: by 2002:a17:902:f552:b0:1d9:732e:8fe6 with SMTP id h18-20020a170902f55200b001d9732e8fe6mr42783plf.16.1707150956594; Mon, 05 Feb 2024 08:35:56 -0800 (PST) ARC-Seal: i=2; a=rsa-sha256; t=1707150956; cv=pass; d=google.com; s=arc-20160816; b=JoFORN6qKXQm3vlsljwQU4iksdn87erSOlcBU+qHYDok7Y89iU1eTa0aV72+IlS2C6 1wdCYjR9HurIhprQTyv2TBq0i9x7+LlGPSWZXz3FohHZBhRNSCeoHdwuS48UlDFjToKR lHr49g5Z7gvWoyznBFDJUDAFa/gxn/Q9JRK4N1Gn4FWrjlXSrbhN2gLVm8+sBzy8Gq8T AagbL9rUr0vntGzvIUTFbEXAH1k++aDcJ5yZt8EyEhXz4FRn4bpLMMEzZ/W4hyXaU4m0 KbTfYuByhCbOQhRypeT+6WNBnbh8JYHDpMFVjPOUEtidTYKC+rV5WiZu+nYdtz0fQopf lwpg== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:from:subject:message-id:references:mime-version :list-unsubscribe:list-subscribe:list-id:precedence:in-reply-to:date :dkim-signature; bh=czI6QKRPuD+UhsFBM8noEszZVdGtsHH2blT9IiCFAMo=; fh=ZUJzRMTIDUin/7LqIXz+BUPUF3nDBPCVccYDn9kFGFE=; b=MwFwgGHYpCWo45fBRVEJf+i2YYyWQUDVk7rJOx8YkFkKwYm/t9HvDMPcHBrQu06mXr 09Xk/UHLqX//TkCf6T072nM016lObWUKOAxxZev9Pt5Kc5OF4/v8ELsXdSiUws3ew6ba iVLVIDAM/nAeejAM24x4juOLFZLMXv+aQ1vkAVZyJ74i1RFSM+1hWiOcAa/nsubYWpXO i/wd0Xgm9pmELPqaAVfUrzlzWiroHDBPmhiFnhMiqZNGqCJ9fJw3fpuHBcCrk+lQeRlJ NfGBFSqqaBMCbR4Mu97WzJJhCnyQ5SwbuEAtP7PAr1KcojisA0WnRNr7HgVCRftZf+qH zGDQ==; dara=google.com ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=b8XJzqh5; arc=pass (i=1 spf=pass spfdomain=flex--vdonnefort.bounces.google.com dkim=pass dkdomain=google.com dmarc=pass fromdomain=google.com); spf=pass (google.com: domain of linux-kernel+bounces-53019-ouuuleilei=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) smtp.mailfrom="linux-kernel+bounces-53019-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com X-Forwarded-Encrypted: i=1; AJvYcCWQwIM3uMHKXdsUSrWGn09yDasiywCmstZo6jBjcM4vqg9cNMna22ERZZ5gQmgOaWmmPj0iUnUp+QRYWpi6EawO/v0c7w== Received: from sv.mirrors.kernel.org (sv.mirrors.kernel.org. [139.178.88.99]) by mx.google.com with ESMTPS id l10-20020a170903120a00b001d94e6aaae8si81885plh.281.2024.02.05.08.35.56 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Feb 2024 08:35:56 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-53019-ouuuleilei=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=b8XJzqh5; arc=pass (i=1 spf=pass spfdomain=flex--vdonnefort.bounces.google.com dkim=pass dkdomain=google.com dmarc=pass fromdomain=google.com); spf=pass (google.com: domain of linux-kernel+bounces-53019-ouuuleilei=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) smtp.mailfrom="linux-kernel+bounces-53019-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sv.mirrors.kernel.org (Postfix) with ESMTPS id 5B11F285016 for ; Mon, 5 Feb 2024 16:35:56 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 163F945940; Mon, 5 Feb 2024 16:34:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="b8XJzqh5" Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 39E9744C6F for ; Mon, 5 Feb 2024 16:34:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707150870; cv=none; b=NfTl0g0sdCXbYWwQxG0eutaFjm7Q1dM7ZRs+IWaoQnpIEeVk70Xky205mJRq6dANBJtF2zyc5vetd8FEifMI8Qhr+qWtPeYH+92iIM2H/keiPf+cPoOkA/AWiq4Mescik5NrDD7Yf+M3b030kDJoGq6Kws1Zzcy1nEKb1844tr8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707150870; c=relaxed/simple; bh=Bqyi0ICVEBYrJJMGXLGA+v+nMZe2jifnBmWShjN4Oew=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=o0C6qEZ3v83DnMgkJp/1pzIm5lCRBPzzdJvfhKQa1B7q2VpEQTi1ZXaxqx5qYON3zVYJZ9HguHYt0s7cE+eOi5sAzEWVztsJiBfhOLlVuYSwtou8BvJXZzBqckJklMa31+rAefnoA2WSxrEAq3Qvn1mjmAav2QmUXDO1Xw5r2Ss= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=b8XJzqh5; arc=none smtp.client-ip=209.85.128.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-40d62d3ae0cso26319865e9.2 for ; Mon, 05 Feb 2024 08:34:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1707150866; x=1707755666; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=czI6QKRPuD+UhsFBM8noEszZVdGtsHH2blT9IiCFAMo=; b=b8XJzqh5UAFYWVdVBErgoiGQ8wrzOcpr6VUFBHCDx3dSZgybfqdxQlp6U/NyKtrFMM kvZNsXjNRe0mVhpG6EyseYDjcKpDcBNrdYLOwDGqAwuoLdN1IfWxeLCMzv23FzNLQtZU +REpwT6AWsxOrvIp26SB5VB8fdZrDREvQIIPLu7I7GAh/qs5hlWq5l8QjqXOKd6BRqOr rslQZmru6l8T+mOho6za8YJpkjHoxBbMbJNkTac4jCpolRiSZScdF9HSzQVMrPpK4jE2 468aUkkb81TMSNLMYM2m+N5E+IVx0iArxAwkdTYEbuhJrStAv5px55GaPxyq65q5FEkL pk5w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707150866; x=1707755666; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=czI6QKRPuD+UhsFBM8noEszZVdGtsHH2blT9IiCFAMo=; b=l0bW4HRdIcyt73sGvyzsNf4BnNZdLxokRYiuE9MXgugbw5GMUXCVQf8pD2GLwMssHa mB4wxn2Md/MBvIbyIg7EOmItVQTqv31IDQLt7Oh5dhqDE7lpG37RQabkp4bGxpSJ7mHA kZTZsvJ42Wv1wYI+6duMZyIXdqMcSwcRW5Yy4ftCyN0DEh3enWAXwm9rr5yKteH4adL6 SH0wLCQX/5Dwsdm1tOChQfNZVWvTXDhdJT7hqhTVbISSywrP3fpQAz9wCyLaobedN05y 9Er8K7GF3xUs0vM8Gy2x/XQY/mHiM09/d7r4mL5z+Ra4ZcNI/6mbnVdSEkeWx7ymTr1T 0+Zw== X-Gm-Message-State: AOJu0YwKkOuw+udcQOdntxx2fM/WDSFRt/MatdnVW7luBaoNLIhUhz7I 6ln7+GE521l+WaF8RoAHP6mAOf6YX6w7PSk6a7jYI6hLu3+uRJUAe57tflGESujZhtiyEx8hmcI hErAzR7+raFKCqBp/gw== X-Received: from vdonnefort.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:2eea]) (user=vdonnefort job=sendgmr) by 2002:a05:600c:b96:b0:40f:df2b:6843 with SMTP id fl22-20020a05600c0b9600b0040fdf2b6843mr590wmb.3.1707150866597; Mon, 05 Feb 2024 08:34:26 -0800 (PST) Date: Mon, 5 Feb 2024 16:34:08 +0000 In-Reply-To: <20240205163410.2296552-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240205163410.2296552-1-vdonnefort@google.com> X-Mailer: git-send-email 2.43.0.594.gd9cf4e227d-goog Message-ID: <20240205163410.2296552-5-vdonnefort@google.com> Subject: [PATCH v14 4/6] tracing: Allow user-space mapping of the ring-buffer From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: mathieu.desnoyers@efficios.com, kernel-team@android.com, Vincent Donnefort X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1790077521586894724 X-GMAIL-MSGID: 1790077521586894724 Currently, user-space extracts data from the ring-buffer via splice, which is handy for storage or network sharing. However, due to splice limitations, it is imposible to do real-time analysis without a copy. A solution for that problem is to let the user-space map the ring-buffer directly. The mapping is exposed via the per-CPU file trace_pipe_raw. The first element of the mapping is the meta-page. It is followed by each subbuffer constituting the ring-buffer, ordered by their unique page ID: * Meta-page -- include/uapi/linux/trace_mmap.h for a description * Subbuf ID 0 * Subbuf ID 1 ... It is therefore easy to translate a subbuf ID into an offset in the mapping: reader_id = meta->reader->id; reader_offset = meta->meta_page_size + reader_id * meta->subbuf_size; When new data is available, the mapper must call a newly introduced ioctl: TRACE_MMAP_IOCTL_GET_READER. This will update the Meta-page reader ID to point to the next reader containing unread data. Mapping will prevent snapshot and buffer size modifications. Signed-off-by: Vincent Donnefort diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h index 182e05a3004a..7330249257e7 100644 --- a/include/uapi/linux/trace_mmap.h +++ b/include/uapi/linux/trace_mmap.h @@ -43,4 +43,6 @@ struct trace_buffer_meta { __u64 Reserved2; }; +#define TRACE_MMAP_IOCTL_GET_READER _IO('T', 0x1) + #endif /* _TRACE_MMAP_H_ */ diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4ebf4d0bd14c..36b62cf2fb3f 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1175,6 +1175,12 @@ static void tracing_snapshot_instance_cond(struct trace_array *tr, return; } + if (tr->mapped) { + trace_array_puts(tr, "*** BUFFER MEMORY MAPPED ***\n"); + trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n"); + return; + } + local_irq_save(flags); update_max_tr(tr, current, smp_processor_id(), cond_data); local_irq_restore(flags); @@ -1307,7 +1313,7 @@ static int tracing_arm_snapshot_locked(struct trace_array *tr) lockdep_assert_held(&trace_types_lock); spin_lock(&tr->snapshot_trigger_lock); - if (tr->snapshot == UINT_MAX) { + if (tr->snapshot == UINT_MAX || tr->mapped) { spin_unlock(&tr->snapshot_trigger_lock); return -EBUSY; } @@ -6533,7 +6539,7 @@ static void tracing_set_nop(struct trace_array *tr) { if (tr->current_trace == &nop_trace) return; - + tr->current_trace->enabled--; if (tr->current_trace->reset) @@ -8652,15 +8658,31 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, return ret; } -/* An ioctl call with cmd 0 to the ring buffer file will wake up all waiters */ static long tracing_buffers_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct ftrace_buffer_info *info = file->private_data; struct trace_iterator *iter = &info->iter; + int err; + + if (cmd == TRACE_MMAP_IOCTL_GET_READER) { + if (!(file->f_flags & O_NONBLOCK)) { + err = ring_buffer_wait(iter->array_buffer->buffer, + iter->cpu_file, + iter->tr->buffer_percent); + if (err) + return err; + } - if (cmd) - return -ENOIOCTLCMD; + return ring_buffer_map_get_reader(iter->array_buffer->buffer, + iter->cpu_file); + } else if (cmd) { + return -ENOTTY; + } + /* + * An ioctl call with cmd 0 to the ring buffer file will wake up all + * waiters + */ mutex_lock(&trace_types_lock); iter->wait_index++; @@ -8673,6 +8695,97 @@ static long tracing_buffers_ioctl(struct file *file, unsigned int cmd, unsigned return 0; } +static vm_fault_t tracing_buffers_mmap_fault(struct vm_fault *vmf) +{ + struct ftrace_buffer_info *info = vmf->vma->vm_file->private_data; + struct trace_iterator *iter = &info->iter; + vm_fault_t ret = VM_FAULT_SIGBUS; + struct page *page; + + page = ring_buffer_map_fault(iter->array_buffer->buffer, iter->cpu_file, + vmf->pgoff); + if (!page) + return ret; + + get_page(page); + vmf->page = page; + vmf->page->mapping = vmf->vma->vm_file->f_mapping; + vmf->page->index = vmf->pgoff; + + return 0; +} + +static void tracing_buffers_mmap_close(struct vm_area_struct *vma) +{ + struct ftrace_buffer_info *info = vma->vm_file->private_data; + struct trace_iterator *iter = &info->iter; + struct trace_array *tr = iter->tr; + + ring_buffer_unmap(iter->array_buffer->buffer, iter->cpu_file); + +#ifdef CONFIG_TRACER_MAX_TRACE + spin_lock(&tr->snapshot_trigger_lock); + if (!WARN_ON(!tr->mapped)) + tr->mapped--; + spin_unlock(&tr->snapshot_trigger_lock); +#endif +} + +static void tracing_buffers_mmap_open(struct vm_area_struct *vma) +{ + struct ftrace_buffer_info *info = vma->vm_file->private_data; + struct trace_iterator *iter = &info->iter; + + WARN_ON(ring_buffer_map(iter->array_buffer->buffer, iter->cpu_file)); +} + +static const struct vm_operations_struct tracing_buffers_vmops = { + .open = tracing_buffers_mmap_open, + .close = tracing_buffers_mmap_close, + .fault = tracing_buffers_mmap_fault, +}; + +static int tracing_buffers_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct ftrace_buffer_info *info = filp->private_data; + struct trace_iterator *iter = &info->iter; + struct trace_array *tr = iter->tr; + int ret = 0; + + if (vma->vm_flags & VM_WRITE) + return -EPERM; + + vm_flags_mod(vma, VM_DONTCOPY | VM_DONTDUMP, VM_MAYWRITE); + vma->vm_ops = &tracing_buffers_vmops; + +#ifdef CONFIG_TRACER_MAX_TRACE + /* + * We hold mmap_lock here. lockdep would be unhappy if we would now take + * trace_types_lock. Instead use the specific snapshot_trigger_lock. + */ + spin_lock(&tr->snapshot_trigger_lock); + if (tr->snapshot || tr->mapped == UINT_MAX) { + spin_unlock(&tr->snapshot_trigger_lock); + return -EBUSY; + } + tr->mapped++; + spin_unlock(&tr->snapshot_trigger_lock); + + /* Wait for update_max_tr() to observe iter->tr->mapped */ + if (tr->mapped == 1) + synchronize_rcu(); +#endif + ret = ring_buffer_map(iter->array_buffer->buffer, iter->cpu_file); +#ifdef CONFIG_TRACER_MAX_TRACE + if (ret) { + spin_lock(&tr->snapshot_trigger_lock); + iter->tr->mapped--; + spin_unlock(&tr->snapshot_trigger_lock); + } +#endif + return ret; +} + static const struct file_operations tracing_buffers_fops = { .open = tracing_buffers_open, .read = tracing_buffers_read, @@ -8681,6 +8794,7 @@ static const struct file_operations tracing_buffers_fops = { .splice_read = tracing_buffers_splice_read, .unlocked_ioctl = tracing_buffers_ioctl, .llseek = no_llseek, + .mmap = tracing_buffers_mmap, }; static ssize_t diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index bd312e9afe25..8a96e7a89e6b 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -336,6 +336,7 @@ struct trace_array { bool allocated_snapshot; spinlock_t snapshot_trigger_lock; unsigned int snapshot; + unsigned int mapped; unsigned long max_latency; #ifdef CONFIG_FSNOTIFY struct dentry *d_max_latency; From patchwork Mon Feb 5 16:34:09 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Donnefort X-Patchwork-Id: 196926 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7301:168b:b0:106:860b:bbdd with SMTP id ma11csp991851dyb; Mon, 5 Feb 2024 08:36:09 -0800 (PST) X-Google-Smtp-Source: AGHT+IHWjcCzzPqwMLI8Af4yIkqgw4h8vhaAfDJH2rkZeCzCQHpUCVreoFGmpt+S3eSythrNNDow X-Received: by 2002:a05:6214:5090:b0:68c:aa46:c624 with SMTP id kk16-20020a056214509000b0068caa46c624mr2766087qvb.24.1707150968827; Mon, 05 Feb 2024 08:36:08 -0800 (PST) ARC-Seal: i=2; a=rsa-sha256; t=1707150968; cv=pass; d=google.com; s=arc-20160816; b=PygoGtXa0ER5R7giriOmXoTeTXXybB8XaZbhkX24PZ00LmZhY7FD2Buvribj1NlqfM EEH7xBtqBfC5sfs6AZ/58Q2xTrJuap3Qi2Xlm8QWmHm/tMmO0rFscyHHJGANXPKUqyaw +fiy5Q2t+uLpEP4RbafhlITSMfapEyjBqIJYjdbQR/hTBD1ILmViGZDufxfmF9P1oNne HcxmiBITdvrdsFTNOMfZkqzlzCFEjPfSPVagLOSGpUzLuMlHH7xQy8p6gRjfX2bmiKuH +1uktTH8EBsUStd+6nS1JlmRgYUOL/ux4weeVmZ1tGh79CAL8cqrj8Zi7AcKiJEFkHLD 5Kkg== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:from:subject:message-id:references:mime-version :list-unsubscribe:list-subscribe:list-id:precedence:in-reply-to:date :dkim-signature; bh=MlKarA43yH71Vjbty3RM0+B2KNuJ6FxA9d0o2uA0tIg=; fh=kSnEJoqgbOWQqI9wG3r3tXDF0g3czLCrVt56yYGiNzQ=; b=dpKiR0f3GoANZG0zKDWvgmNcg5B+6xn01MBAW3FLbh2oflhlb3z5nMKXKBeEvcavsy 82PbSRSVcp5tSPih3s6SVoUvvnZ8v1kFM0kHi+bpL0sVgxVMMA+Kj+5AclDAk0IvU8kK irAC5bSPxLMZduLp5ZihQaJWnfLJ2b475WM9ht8dRid/u6/SXhu1YhVHz3uQAosr6jXP qlJfAQ9Xs6+J/qtxBwCsBY2loj3p+liglh5XeUdfd1xMci28GJH5cKjuKWqgQpEGH5rf qKISrY2QwTCND4qipmJFNHzghTevjD1v0avbDxsKVfxbGogt4H//ZxKNrrbCgk/Oce5i qy+A==; dara=google.com ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=Cl+6aiHP; arc=pass (i=1 spf=pass spfdomain=flex--vdonnefort.bounces.google.com dkim=pass dkdomain=google.com dmarc=pass fromdomain=google.com); spf=pass (google.com: domain of linux-kernel+bounces-53020-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) smtp.mailfrom="linux-kernel+bounces-53020-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com X-Forwarded-Encrypted: i=1; AJvYcCW+nvBZW6pN5yOXsRry8VVWt040hlCrTmqfPBhEel4kDFcCLh+59XM7b52Y5TZfmIJjCtrAidWv0nlTMIXY+O1Y/NymnA== Received: from ny.mirrors.kernel.org (ny.mirrors.kernel.org. [147.75.199.223]) by mx.google.com with ESMTPS id 14-20020a0562140d0e00b0068ca83708e6si287141qvh.343.2024.02.05.08.36.08 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Feb 2024 08:36:08 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-53020-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) client-ip=147.75.199.223; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=Cl+6aiHP; arc=pass (i=1 spf=pass spfdomain=flex--vdonnefort.bounces.google.com dkim=pass dkdomain=google.com dmarc=pass fromdomain=google.com); spf=pass (google.com: domain of linux-kernel+bounces-53020-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) smtp.mailfrom="linux-kernel+bounces-53020-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ny.mirrors.kernel.org (Postfix) with ESMTPS id B4D241C2237C for ; Mon, 5 Feb 2024 16:36:06 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id D35754779C; Mon, 5 Feb 2024 16:34:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Cl+6aiHP" Received: from mail-wr1-f73.google.com (mail-wr1-f73.google.com [209.85.221.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 93D9344C92 for ; Mon, 5 Feb 2024 16:34:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707150872; cv=none; b=caPiyEs9Q6dNUOSXCDrYv70acr18Toc/lKmkegnOpcBreoTTeY0LPJYj7n2uFi682YxEvzKYq9vtp1DcmfDZr2L2tziUm2GtnmYgi5J0NmgBEa/7PZFW3TMItGzl2byvOUVltM/9CsHWQgZfM9g4pd3KsjT+s+NiNfVI1uv/Nkw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707150872; c=relaxed/simple; bh=R5o/R3ePscrxpSb0R1Xmqc1DrGhjORR4iN3JNJ+9WVo=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=CK4ORdoUA7CoAmcADKVGKu2HxXW7wFhiGNzwAIFqxbQos4QG6OAgIEKji0/1WuB4Pll3frGytsmF3zxaIKYWPYNi/tomkYdjKk0IHOsLmnQKKPYUoA0VL6y1Pv6rvk8UDqk2BxuRHkSCN/1mepn8+J9Ook+fivoAkYKvfklWHQ0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=Cl+6aiHP; arc=none smtp.client-ip=209.85.221.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Received: by mail-wr1-f73.google.com with SMTP id ffacd0b85a97d-33b0c264abbso2436493f8f.2 for ; Mon, 05 Feb 2024 08:34:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1707150869; x=1707755669; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=MlKarA43yH71Vjbty3RM0+B2KNuJ6FxA9d0o2uA0tIg=; b=Cl+6aiHPjphQcAPgVl3+pCSTHRn5D/8tO0L56/m1W0O+SpgECYKuWSwOko/ASk9f+4 5HXMEnTYgWyyZQQdz4e2KuCCBglzkayp5ByIjMAyWmYGJqcv8Nze9LMb/cMJQqPLORhL IqIcl/8yJtjE3AeGovMXzugBDIwIQw8VUCdYPnEzvfFo9JIXMUtdJHEo288YYCp9pGNe e82q6bP/tZYJ10jLw13rUeZmXTgBvQE3+o76uJZIGK2qOWIRjg420pdqxbnglKqsnL1V V7Wj17ANze6+hZqacUvx5byt0zyvXPC1bwpd7a92aa3U9LTx4AJJrgXA5ahiZSrQlS6B LKIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707150869; x=1707755669; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=MlKarA43yH71Vjbty3RM0+B2KNuJ6FxA9d0o2uA0tIg=; b=XJu3YuKb5nxgeVqM/BVnsRj9gzSZVgmCrdF7F/m2bHi4zxxWZvetx11Rf6uZIQI7aj E4kt3fzXm9UKcAdHRgyaNeMrcxtDFOOeqiR8SAtdhI9lxcGNwGokZGESlwtFKoFV2IQF 6o9tiOrTguJjiNe/9Qx83y5ERJ6iWvRLE+Wfi42GIsPRNj3BUGArDsVjUoA1Pdgf36iM JkGQs/17N6zUDpKniiy+2Gewt+QMUvBXNA+dcfIy9Vq0ROKpyRRUMGDoMXoTYSfLoJQi AumMC1m41vOtz2vGURL/7DjUDALSca8B9h229kw1CBqXGPAslhHjBx6u+D/o/MmK3pvI r1lw== X-Gm-Message-State: AOJu0YxKUQHrA5K474/RBPIlzQPwpBPgj/Od9QgQWGDGyFyN5Yw1dAmT b24HxBCuTwH5nO0Kee1hcat/5SsR+G3cXfiTqKwHEP5X9fMwSXBrfnLWCZzQ8QV2TilgXtn/RHr vPJ2yWjYaHvM/WT68ow== X-Received: from vdonnefort.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:2eea]) (user=vdonnefort job=sendgmr) by 2002:a05:6000:70f:b0:33b:d17:296f with SMTP id bs15-20020a056000070f00b0033b0d17296fmr73wrb.3.1707150868822; Mon, 05 Feb 2024 08:34:28 -0800 (PST) Date: Mon, 5 Feb 2024 16:34:09 +0000 In-Reply-To: <20240205163410.2296552-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240205163410.2296552-1-vdonnefort@google.com> X-Mailer: git-send-email 2.43.0.594.gd9cf4e227d-goog Message-ID: <20240205163410.2296552-6-vdonnefort@google.com> Subject: [PATCH v14 5/6] Documentation: tracing: Add ring-buffer mapping From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: mathieu.desnoyers@efficios.com, kernel-team@android.com, Vincent Donnefort X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1790077533936388814 X-GMAIL-MSGID: 1790077533936388814 It is now possible to mmap() a ring-buffer to stream its content. Add some documentation and a code example. Signed-off-by: Vincent Donnefort diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst index 5092d6c13af5..0b300901fd75 100644 --- a/Documentation/trace/index.rst +++ b/Documentation/trace/index.rst @@ -29,6 +29,7 @@ Linux Tracing Technologies timerlat-tracer intel_th ring-buffer-design + ring-buffer-map stm sys-t coresight/index diff --git a/Documentation/trace/ring-buffer-map.rst b/Documentation/trace/ring-buffer-map.rst new file mode 100644 index 000000000000..628254e63830 --- /dev/null +++ b/Documentation/trace/ring-buffer-map.rst @@ -0,0 +1,104 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================== +Tracefs ring-buffer memory mapping +================================== + +:Author: Vincent Donnefort + +Overview +======== +Tracefs ring-buffer memory map provides an efficient method to stream data +as no memory copy is necessary. The application mapping the ring-buffer becomes +then a consumer for that ring-buffer, in a similar fashion to trace_pipe. + +Memory mapping setup +==================== +The mapping works with a mmap() of the trace_pipe_raw interface. + +The first system page of the mapping contains ring-buffer statistics and +description. It is referred as the meta-page. One of the most important field of +the meta-page is the reader. It contains the sub-buffer ID which can be safely +read by the mapper (see ring-buffer-design.rst). + +The meta-page is followed by all the sub-buffers, ordered by ascendant ID. It is +therefore effortless to know where the reader starts in the mapping: + +.. code-block:: c + + reader_id = meta->reader->id; + reader_offset = meta->meta_page_size + reader_id * meta->subbuf_size; + +When the application is done with the current reader, it can get a new one using +the trace_pipe_raw ioctl() TRACE_MMAP_IOCTL_GET_READER. This ioctl also updates +the meta-page fields. + +Limitations +=========== +When a mapping is in place on a Tracefs ring-buffer, it is not possible to +either resize it (either by increasing the entire size of the ring-buffer or +each subbuf). It is also not possible to use snapshot or splice. + +Concurrent readers (either another application mapping that ring-buffer or the +kernel with trace_pipe) are allowed but not recommended. They will compete for +the ring-buffer and the output is unpredictable. + +Example +======= + +.. code-block:: c + + #include + #include + #include + #include + + #include + + #include + #include + + #define TRACE_PIPE_RAW "/sys/kernel/tracing/per_cpu/cpu0/trace_pipe_raw" + + int main(void) + { + int page_size = getpagesize(), fd, reader_id; + unsigned long meta_len, data_len; + struct trace_buffer_meta *meta; + void *map, *reader, *data; + + fd = open(TRACE_PIPE_RAW, O_RDONLY | O_NONBLOCK); + if (fd < 0) + exit(EXIT_FAILURE); + + map = mmap(NULL, page_size, PROT_READ, MAP_SHARED, fd, 0); + if (map == MAP_FAILED) + exit(EXIT_FAILURE); + + meta = (struct trace_buffer_meta *)map; + meta_len = meta->meta_page_size; + + printf("entries: %llu\n", meta->entries); + printf("overrun: %llu\n", meta->overrun); + printf("read: %llu\n", meta->read); + printf("nr_subbufs: %u\n", meta->nr_subbufs); + + data_len = meta->subbuf_size * meta->nr_subbufs; + data = mmap(NULL, data_len, PROT_READ, MAP_SHARED, fd, meta_len); + if (data == MAP_FAILED) + exit(EXIT_FAILURE); + + if (ioctl(fd, TRACE_MMAP_IOCTL_GET_READER) < 0) + exit(EXIT_FAILURE); + + reader_id = meta->reader.id; + reader = data + meta->subbuf_size * reader_id; + + printf("Current reader address: %p\n", reader); + + munmap(data, data_len); + munmap(meta, meta_len); + close (fd); + + return 0; + } From patchwork Mon Feb 5 16:34:10 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Donnefort X-Patchwork-Id: 196927 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7301:168b:b0:106:860b:bbdd with SMTP id ma11csp992229dyb; Mon, 5 Feb 2024 08:36:48 -0800 (PST) X-Google-Smtp-Source: AGHT+IEyrsRiZkowwz5STjAawE6evYpMKbL/Mx1MlKlTiF0jy+MvYfVcyrbSKOfYe2rkKK7CgvDq X-Received: by 2002:a17:907:368b:b0:a2e:acd2:1fe1 with SMTP id bi11-20020a170907368b00b00a2eacd21fe1mr9112796ejc.73.1707151008135; Mon, 05 Feb 2024 08:36:48 -0800 (PST) ARC-Seal: i=2; a=rsa-sha256; t=1707151008; cv=pass; d=google.com; s=arc-20160816; b=spfF4iryOD5Q0oonHd7F/YJuOzmoGvwUZDeA8QujQ8ilTA5yTxjhN/vMpGSzTeKnpv JD6h7gQPW+sF6WsN2oVKvPFomxAdsRSRa+03gMx5GSd26dFBLa6DLXDos9IhL6GuzTLD xUKY1Wg05MumcL3IWhp0QPh8wQrZE+MtefHIXzA9Ixj7fsDws0zcK/MJOBh+ccJMHcMO GMm3NJ6wUU5bVQbPbkqqQdNhXkNfznlO+l2LDU/I7QaHOtjLCVlw8AkOWsNGxa71ceSi CmJ2wtx6zemIz0PRfv/+NEpk3NecXIXUEzSa3CIW1r9qwLBkUvflreoelzznQCCYZ0TM tR1g== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:from:subject:message-id:references:mime-version :list-unsubscribe:list-subscribe:list-id:precedence:in-reply-to:date :dkim-signature; bh=7nCPlQ//tobDi8AcCVhpF3SWhFnBTJGSmof7x/XHBwM=; fh=ebzT1zHiQtUXD0LbxRIbUj8oVJ/IvfxWfCmMqBPSq/4=; b=MetBUJ8D/fcy4dTiSjpek6KV5aVo3it1Epl9en1sDOpN0T6CnUWTpqzcEJwUzHnDRj lBBGn70v2RYM6NcGyen0tfWqyCfW79FjYd9wuFVcNY6W9lrasm7zKqnqN3Kdy4CmKHky F2kKs3Yc+PU8q77lcbgWOeym5H0qsmuTzsRD/s3tIkED4s8DY9j2BCjgEIH9GpKoMSNC UtF2M4jZ+MLr9wFkfnI7SI8D/qB2jPZqi8THRFdzPeatK6cMTCrQ7d7v+Rxt9XcdAp6j PIYfFbC0y4nvwQWQ6PDlTQ2aO9rX7hdSwmxKHsVt0rDann7KhGfCoBZq0HeRdPU9gYHJ JZAA==; dara=google.com ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=1TiOgOQN; arc=pass (i=1 spf=pass spfdomain=flex--vdonnefort.bounces.google.com dkim=pass dkdomain=google.com dmarc=pass fromdomain=google.com); spf=pass (google.com: domain of linux-kernel+bounces-53021-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) smtp.mailfrom="linux-kernel+bounces-53021-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com X-Forwarded-Encrypted: i=1; AJvYcCWA2+NKVT/2PTRKQH0GEyL+9HCMXl90pFBjLRsjzqAPNC8MMWERHbcy1MKvhvdlB92lv5meA634rGMMfegII5FwwuP9Dw== Received: from am.mirrors.kernel.org (am.mirrors.kernel.org. [2604:1380:4601:e00::3]) by mx.google.com with ESMTPS id h16-20020a17090634d000b00a359f156766si3238ejb.869.2024.02.05.08.36.47 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Feb 2024 08:36:48 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-53021-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=1TiOgOQN; arc=pass (i=1 spf=pass spfdomain=flex--vdonnefort.bounces.google.com dkim=pass dkdomain=google.com dmarc=pass fromdomain=google.com); spf=pass (google.com: domain of linux-kernel+bounces-53021-ouuuleilei=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) smtp.mailfrom="linux-kernel+bounces-53021-ouuuleilei=gmail.com@vger.kernel.org"; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by am.mirrors.kernel.org (Postfix) with ESMTPS id 4B0311F23C68 for ; Mon, 5 Feb 2024 16:36:22 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 50D6347F65; Mon, 5 Feb 2024 16:34:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="1TiOgOQN" Received: from mail-yb1-f201.google.com (mail-yb1-f201.google.com [209.85.219.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 15D5D45941 for ; Mon, 5 Feb 2024 16:34:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707150875; cv=none; b=ObgSl+w4ewIvzhRsYPO/Wkez9K/z9Ewcl7DtCLsjHDL8H3bbfYBHF7kNexyF+fm4OPKWC5rIXYQRjC5/4YF//D7IUlYit22FkCyWPQV2DTHJgo+bCJK/ViQnv4EHXjwSacxOYucsgKS7FqoO1qYMQgS39LDUjJV6bswLlqKjnNU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707150875; c=relaxed/simple; bh=OFqHbKxqsaW9GPflVeJXijHkDF7anI9AJhhg0gch2Vk=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=g0PDtgU8tLShgkTNzeCOSyLq/mEW+CRNzV3IzM0vVC99ZVPgisO3YM26crcxDOzwq3EpDgVg5mw2Grkv1vP/SPU3MfaghF/zhZiQe4z270jXlY7xV7hu+jh4bw3Nrm9pnqysuFb9ifspERWd/+/Ex4EQnP00oGHLlVOwKY4WIFQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=1TiOgOQN; arc=none smtp.client-ip=209.85.219.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Received: by mail-yb1-f201.google.com with SMTP id 3f1490d57ef6-dc6b26845cdso7704328276.3 for ; Mon, 05 Feb 2024 08:34:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1707150871; x=1707755671; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=7nCPlQ//tobDi8AcCVhpF3SWhFnBTJGSmof7x/XHBwM=; b=1TiOgOQNYacjyisUlqy4z3uYDTadnwbsPgFj6XRMnb0As+A1FfGOMYFZh9KHsLp4uz AOs3m7ZZ+gcmwGY1fXKwBpGNakr85ftKjYvScH1rBX9VcGSo7oSzHZ+wjexjqz8PzOI/ NHAU5X6O8ZFnns72DDd0jdaJaTdFXPf5o1uqhFfFKBwuHoKXFBvb+c1LcsvRVWRffKut azGhKfU/LBVXYOrygsZhbvCVBVV/bhAjwO6pr+OE3ETgm1Vg45s7/jkq9897qE7ddNFt KFhLt9QFnMzMdBbLN7bJK2RMHaoTgI4ZIZY2wqrXJKYC0UqpLm+qxRkau06gFsSwjOoC xExA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707150871; x=1707755671; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=7nCPlQ//tobDi8AcCVhpF3SWhFnBTJGSmof7x/XHBwM=; b=OJaoINUtN/y4Jbj02gnuaAgW91di0f8rZdcqXzEAXYYwhLZR2KvWzH2hveBYZ0VHgD kXTudnj/wWYN0iSGo4WeIXbLHoAJpsdeu3ZeOB+fQwtGWWlb51fprDcYxQMDr6j6O3tG 3iE8uq2NhFvAVrf+SUTTzrp3tDp+xugaflfPKjPpOSoJrb3yD5TQAgrUSib1M3BPq3Qq ibyAf08o16RUA8Byb/u7nkxRBQ2s3u8KuHZJ6z2bMR4wQzsGIHByY7cmlUOl3Pd4DWcf hQfkFfOyMmIRtK9aqo4NToyoYo1qT2ZGh0RNOs14yV/E21hhTdZAplvUFqG8HmbFsQvR r51g== X-Gm-Message-State: AOJu0Ywk2fXpKXU8j9xbgPXcAgoFTpkKahdueZHEyd847ervYCMxK11a C2zIM/F5rmKIz8NWXVRgX6bOuT8rp5rLDvbELz8xac5yy5Q7JmJs2MPW4tDROhDAefayl9t+SVh Jes6v9CnoaX4GXDLSJw== X-Received: from vdonnefort.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:2eea]) (user=vdonnefort job=sendgmr) by 2002:a05:6902:108e:b0:dbd:b165:441 with SMTP id v14-20020a056902108e00b00dbdb1650441mr2939257ybu.0.1707150871178; Mon, 05 Feb 2024 08:34:31 -0800 (PST) Date: Mon, 5 Feb 2024 16:34:10 +0000 In-Reply-To: <20240205163410.2296552-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240205163410.2296552-1-vdonnefort@google.com> X-Mailer: git-send-email 2.43.0.594.gd9cf4e227d-goog Message-ID: <20240205163410.2296552-7-vdonnefort@google.com> Subject: [PATCH v14 6/6] ring-buffer/selftest: Add ring-buffer mapping test From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: mathieu.desnoyers@efficios.com, kernel-team@android.com, Vincent Donnefort , Shuah Khan , Shuah Khan , linux-kselftest@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1790077575214866849 X-GMAIL-MSGID: 1790077575214866849 This test maps a ring-buffer and validate the meta-page after reset and after emitting few events. Cc: Shuah Khan Cc: Shuah Khan Cc: linux-kselftest@vger.kernel.org Signed-off-by: Vincent Donnefort diff --git a/tools/testing/selftests/ring-buffer/Makefile b/tools/testing/selftests/ring-buffer/Makefile new file mode 100644 index 000000000000..627c5fa6d1ab --- /dev/null +++ b/tools/testing/selftests/ring-buffer/Makefile @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0 +CFLAGS += -Wl,-no-as-needed -Wall +CFLAGS += $(KHDR_INCLUDES) +CFLAGS += -D_GNU_SOURCE + +TEST_GEN_PROGS = map_test + +include ../lib.mk diff --git a/tools/testing/selftests/ring-buffer/config b/tools/testing/selftests/ring-buffer/config new file mode 100644 index 000000000000..d936f8f00e78 --- /dev/null +++ b/tools/testing/selftests/ring-buffer/config @@ -0,0 +1,2 @@ +CONFIG_FTRACE=y +CONFIG_TRACER_SNAPSHOT=y diff --git a/tools/testing/selftests/ring-buffer/map_test.c b/tools/testing/selftests/ring-buffer/map_test.c new file mode 100644 index 000000000000..56c44b29d998 --- /dev/null +++ b/tools/testing/selftests/ring-buffer/map_test.c @@ -0,0 +1,273 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Ring-buffer memory mapping tests + * + * Copyright (c) 2024 Vincent Donnefort + */ +#include +#include +#include +#include +#include +#include + +#include + +#include +#include + +#include "../user_events/user_events_selftests.h" /* share tracefs setup */ +#include "../kselftest_harness.h" + +#define TRACEFS_ROOT "/sys/kernel/tracing" + +static int __tracefs_write(const char *path, const char *value) +{ + int fd, ret; + + fd = open(path, O_WRONLY | O_TRUNC); + if (fd < 0) + return fd; + + ret = write(fd, value, strlen(value)); + + close(fd); + + return ret == -1 ? -errno : 0; +} + +static int __tracefs_write_int(const char *path, int value) +{ + char *str; + int ret; + + if (asprintf(&str, "%d", value) < 0) + return -1; + + ret = __tracefs_write(path, str); + + free(str); + + return ret; +} + +#define tracefs_write_int(path, value) \ + ASSERT_EQ(__tracefs_write_int((path), (value)), 0) + +#define tracefs_write(path, value) \ + ASSERT_EQ(__tracefs_write((path), (value)), 0) + +static int tracefs_reset(void) +{ + if (__tracefs_write_int(TRACEFS_ROOT"/tracing_on", 0)) + return -1; + if (__tracefs_write(TRACEFS_ROOT"/trace", "")) + return -1; + if (__tracefs_write(TRACEFS_ROOT"/set_event", "")) + return -1; + if (__tracefs_write(TRACEFS_ROOT"/current_tracer", "nop")) + return -1; + + return 0; +} + +struct tracefs_cpu_map_desc { + struct trace_buffer_meta *meta; + void *data; + int cpu_fd; +}; + +int tracefs_cpu_map(struct tracefs_cpu_map_desc *desc, int cpu) +{ + unsigned long meta_len, data_len; + int page_size = getpagesize(); + char *cpu_path; + void *map; + + if (asprintf(&cpu_path, + TRACEFS_ROOT"/per_cpu/cpu%d/trace_pipe_raw", + cpu) < 0) + return -ENOMEM; + + desc->cpu_fd = open(cpu_path, O_RDONLY | O_NONBLOCK); + free(cpu_path); + if (desc->cpu_fd < 0) + return -ENODEV; + + map = mmap(NULL, page_size, PROT_READ, MAP_SHARED, desc->cpu_fd, 0); + if (map == MAP_FAILED) + return -errno; + + desc->meta = (struct trace_buffer_meta *)map; + + meta_len = desc->meta->meta_page_size; + data_len = desc->meta->subbuf_size * desc->meta->nr_subbufs; + + map = mmap(NULL, data_len, PROT_READ, MAP_SHARED, desc->cpu_fd, meta_len); + if (map == MAP_FAILED) { + munmap(desc->meta, desc->meta->meta_page_size); + return -EINVAL; + } + + desc->data = map; + + return 0; +} + +void tracefs_cpu_unmap(struct tracefs_cpu_map_desc *desc) +{ + munmap(desc->data, desc->meta->subbuf_size * desc->meta->nr_subbufs); + munmap(desc->meta, desc->meta->meta_page_size); + close(desc->cpu_fd); +} + +FIXTURE(map) { + struct tracefs_cpu_map_desc map_desc; + bool umount; +}; + +FIXTURE_VARIANT(map) { + int subbuf_size; +}; + +FIXTURE_VARIANT_ADD(map, subbuf_size_4k) { + .subbuf_size = 4, +}; + +FIXTURE_VARIANT_ADD(map, subbuf_size_8k) { + .subbuf_size = 8, +}; + +FIXTURE_SETUP(map) +{ + int cpu = sched_getcpu(); + cpu_set_t cpu_mask; + bool fail, umount; + char *message; + + if (!tracefs_enabled(&message, &fail, &umount)) { + if (fail) { + TH_LOG("Tracefs setup failed: %s", message); + ASSERT_FALSE(fail); + } + SKIP(return, "Skipping: %s", message); + } + + self->umount = umount; + + ASSERT_GE(cpu, 0); + + ASSERT_EQ(tracefs_reset(), 0); + + tracefs_write_int(TRACEFS_ROOT"/buffer_subbuf_size_kb", variant->subbuf_size); + + ASSERT_EQ(tracefs_cpu_map(&self->map_desc, cpu), 0); + + /* + * Ensure generated events will be found on this very same ring-buffer. + */ + CPU_ZERO(&cpu_mask); + CPU_SET(cpu, &cpu_mask); + ASSERT_EQ(sched_setaffinity(0, sizeof(cpu_mask), &cpu_mask), 0); +} + +FIXTURE_TEARDOWN(map) +{ + tracefs_reset(); + + if (self->umount) + tracefs_unmount(); + + tracefs_cpu_unmap(&self->map_desc); +} + +TEST_F(map, meta_page_check) +{ + struct tracefs_cpu_map_desc *desc = &self->map_desc; + int cnt = 0; + + ASSERT_EQ(desc->meta->entries, 0); + ASSERT_EQ(desc->meta->overrun, 0); + ASSERT_EQ(desc->meta->read, 0); + + ASSERT_EQ(desc->meta->reader.id, 0); + ASSERT_EQ(desc->meta->reader.read, 0); + + ASSERT_EQ(ioctl(desc->cpu_fd, TRACE_MMAP_IOCTL_GET_READER), 0); + ASSERT_EQ(desc->meta->reader.id, 0); + + tracefs_write_int(TRACEFS_ROOT"/tracing_on", 1); + for (int i = 0; i < 16; i++) + tracefs_write_int(TRACEFS_ROOT"/trace_marker", i); +again: + ASSERT_EQ(ioctl(desc->cpu_fd, TRACE_MMAP_IOCTL_GET_READER), 0); + + ASSERT_EQ(desc->meta->entries, 16); + ASSERT_EQ(desc->meta->overrun, 0); + ASSERT_EQ(desc->meta->read, 16); + + ASSERT_EQ(desc->meta->reader.id, 1); + + if (!(cnt++)) + goto again; +} + +FIXTURE(snapshot) { + bool umount; +}; + +FIXTURE_SETUP(snapshot) +{ + bool fail, umount; + struct stat sb; + char *message; + + if (stat(TRACEFS_ROOT"/snapshot", &sb)) + SKIP(return, "Skipping: %s", "snapshot not available"); + + if (!tracefs_enabled(&message, &fail, &umount)) { + if (fail) { + TH_LOG("Tracefs setup failed: %s", message); + ASSERT_FALSE(fail); + } + SKIP(return, "Skipping: %s", message); + } + + self->umount = umount; +} + +FIXTURE_TEARDOWN(snapshot) +{ + __tracefs_write(TRACEFS_ROOT"/events/sched/sched_switch/trigger", + "!snapshot"); + tracefs_reset(); + + if (self->umount) + tracefs_unmount(); +} + +TEST_F(snapshot, excludes_map) +{ + struct tracefs_cpu_map_desc map_desc; + int cpu = sched_getcpu(); + + ASSERT_GE(cpu, 0); + tracefs_write(TRACEFS_ROOT"/events/sched/sched_switch/trigger", + "snapshot"); + ASSERT_EQ(tracefs_cpu_map(&map_desc, cpu), -EBUSY); +} + +TEST_F(snapshot, excluded_by_map) +{ + struct tracefs_cpu_map_desc map_desc; + int cpu = sched_getcpu(); + + ASSERT_EQ(tracefs_cpu_map(&map_desc, cpu), 0); + + ASSERT_EQ(__tracefs_write(TRACEFS_ROOT"/events/sched/sched_switch/trigger", + "snapshot"), -EBUSY); + ASSERT_EQ(__tracefs_write(TRACEFS_ROOT"/snapshot", + "1"), -EBUSY); +} + +TEST_HARNESS_MAIN