From patchwork Fri Oct 13 16:03:50 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 152634 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:612c:2908:b0:403:3b70:6f57 with SMTP id ib8csp1997306vqb; Fri, 13 Oct 2023 09:08:07 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHvmiYnN8DzoTIyddzlAdN26VHAbaRz1zJVi5NGz0sz2ndDyL8Cn12BZDlDnQe2+ojTGjgw X-Received: by 2002:a17:902:ce84:b0:1c6:9312:187 with SMTP id f4-20020a170902ce8400b001c693120187mr29872865plg.3.1697213286981; Fri, 13 Oct 2023 09:08:06 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1697213286; cv=none; d=google.com; s=arc-20160816; b=XTBVSMvXMLWL+7nNmbOubs/LM7g6IdtzZkxCq04WnC8aETeR3puob/9m6x7VPFtHlq RDxxSfcEojr5m3xwvKoOAaA9sBlJN7iyhN55DkcO465r4M4cYY3ExA36TiU/Xg4MxPtb nkhAZ/qmxBv9MhdH10KHlqtyuDIZWkGtHf2cUiLM3pL2V61clop567qVFL5dodbtlSlu wu958vjnpmAwkLG/pgLqpGlAR7f6mVfYXmqugWSXF+TCp258QlT479enxrcbKATU2CRD ExtRuyt90aeeyk9JTaw6i9fIGM38HK82ul2tzCEEVCFL3ZnRvd11tfzRpskAQSzk5+LZ EqZQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=H+1i5F1S+6wxwGtTBxUYE1F0fETWm68EZav8/D9/C4o=; fh=QCasRecNkSMoqSQLnZiX89u33dCID3L05AOtURpI2pA=; b=yEYPn5Aczgn17BqELV6nBRnjPaENqTU9TzNYhauAemkUxzavnrkEbUVCEJbzL4f2o7 HgS0wessv+CwVXqbmHRwhNuDoPmPhoKwGHTv6ttTXMeHX054D+CNvASiXNluDA0gFBjf gKBQ0andyQeeu50MlPu0WsavdOb2mmH+rS9J50ONDDPUBrhZun3DMYt72NiLwxD/tV9z iDF0vKmhOAMg7ONbotF06ynx1y7N/Q32uXdE+mzGR5k9DH6O/lpQ4l2gXiM7xy2DWhFz G3pmjtQouyQOOVT+syfreMiiDZTrRdIpQPR/eB/mzARpMV/lE+hYmpafqIMedkeccyW7 NnCA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b="ZtW2Gw/X"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:1 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from morse.vger.email (morse.vger.email. [2620:137:e000::3:1]) by mx.google.com with ESMTPS id q6-20020a170902dac600b001bc079974dbsi5223064plx.355.2023.10.13.09.08.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Oct 2023 09:08:06 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:1 as permitted sender) client-ip=2620:137:e000::3:1; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b="ZtW2Gw/X"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:1 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by morse.vger.email (Postfix) with ESMTP id 0553C8205FEC; Fri, 13 Oct 2023 09:08:04 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at morse.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232444AbjJMQHu (ORCPT + 19 others); Fri, 13 Oct 2023 12:07:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232815AbjJMQG4 (ORCPT ); Fri, 13 Oct 2023 12:06:56 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 658ECD5B for ; Fri, 13 Oct 2023 09:05:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1697213147; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=H+1i5F1S+6wxwGtTBxUYE1F0fETWm68EZav8/D9/C4o=; b=ZtW2Gw/XVHVexYiu86nALj4Mq2TSSHcbHJkzrCywlNPpKw4gF09g2uO61gdaRTReuipjrG fiUIHQjWQTGoeBTrcxrO1AdgHIm0pImOyqDBRxBhN/Pn3AxxIP1EiOcAROq8O+7ZbwLQ/A fz0SPxEnzeyMfIewtddnmfswq2M6I+k= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-48-CiGEkiPFOyWFt3PkgwJsGg-1; Fri, 13 Oct 2023 12:05:43 -0400 X-MC-Unique: CiGEkiPFOyWFt3PkgwJsGg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E7945280FEC5; Fri, 13 Oct 2023 16:05:41 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.226]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6C8361C060DF; Fri, 13 Oct 2023 16:05:39 +0000 (UTC) From: David Howells To: Jeff Layton , Steve French Cc: David Howells , Matthew Wilcox , Marc Dionne , Paulo Alcantara , Shyam Prasad N , Tom Talpey , Dominique Martinet , Ilya Dryomov , Christian Brauner , linux-afs@lists.infradead.org, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-cachefs@redhat.com Subject: [RFC PATCH 21/53] netfs: Make the refcounting of netfs_begin_read() easier to use Date: Fri, 13 Oct 2023 17:03:50 +0100 Message-ID: <20231013160423.2218093-22-dhowells@redhat.com> In-Reply-To: <20231013160423.2218093-1-dhowells@redhat.com> References: <20231013160423.2218093-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.7 X-Spam-Status: No, score=-0.9 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on morse.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (morse.vger.email [0.0.0.0]); Fri, 13 Oct 2023 09:08:04 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1779657119824226689 X-GMAIL-MSGID: 1779657119824226689 Make the refcounting of netfs_begin_read() easier to use by not eating the caller's ref on the netfs_io_request it's given. This makes it easier to use when we need to look in the request struct after. Signed-off-by: David Howells cc: Jeff Layton cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- fs/netfs/buffered_read.c | 6 +++++- fs/netfs/io.c | 28 +++++++++++++--------------- include/trace/events/netfs.h | 9 +++++---- 3 files changed, 23 insertions(+), 20 deletions(-) diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index 3b7eb706f2fe..05824f73cfc7 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -217,6 +217,7 @@ void netfs_readahead(struct readahead_control *ractl) ; netfs_begin_read(rreq, false); + netfs_put_request(rreq, false, netfs_rreq_trace_put_return); return; cleanup_free: @@ -267,7 +268,9 @@ int netfs_read_folio(struct file *file, struct folio *folio) iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages, rreq->start, rreq->len); - return netfs_begin_read(rreq, true); + ret = netfs_begin_read(rreq, true); + netfs_put_request(rreq, false, netfs_rreq_trace_put_return); + return ret; discard: netfs_put_request(rreq, false, netfs_rreq_trace_put_discard); @@ -436,6 +439,7 @@ int netfs_write_begin(struct netfs_inode *ctx, ret = netfs_begin_read(rreq, true); if (ret < 0) goto error; + netfs_put_request(rreq, false, netfs_rreq_trace_put_return); have_folio: ret = folio_wait_fscache_killable(folio); diff --git a/fs/netfs/io.c b/fs/netfs/io.c index c80b8eed1209..1795f8679be9 100644 --- a/fs/netfs/io.c +++ b/fs/netfs/io.c @@ -362,6 +362,7 @@ static void netfs_rreq_assess(struct netfs_io_request *rreq, bool was_async) netfs_rreq_unlock_folios(rreq); + trace_netfs_rreq(rreq, netfs_rreq_trace_wake_ip); clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &rreq->flags); wake_up_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS); @@ -657,7 +658,6 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync) if (rreq->len == 0) { pr_err("Zero-sized read [R=%x]\n", rreq->debug_id); - netfs_put_request(rreq, false, netfs_rreq_trace_put_zero_len); return -EIO; } @@ -669,12 +669,10 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync) INIT_WORK(&rreq->work, netfs_rreq_work); - if (sync) - netfs_get_request(rreq, netfs_rreq_trace_get_hold); - /* Chop the read into slices according to what the cache and the netfs * want and submit each one. */ + netfs_get_request(rreq, netfs_rreq_trace_get_for_outstanding); atomic_set(&rreq->nr_outstanding, 1); io_iter = rreq->io_iter; do { @@ -684,25 +682,25 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync) } while (rreq->submitted < rreq->len); if (sync) { - /* Keep nr_outstanding incremented so that the ref always belongs to - * us, and the service code isn't punted off to a random thread pool to - * process. + /* Keep nr_outstanding incremented so that the ref always + * belongs to us, and the service code isn't punted off to a + * random thread pool to process. Note that this might start + * further work, such as writing to the cache. */ - for (;;) { - wait_var_event(&rreq->nr_outstanding, - atomic_read(&rreq->nr_outstanding) == 1); + wait_var_event(&rreq->nr_outstanding, + atomic_read(&rreq->nr_outstanding) == 1); + if (atomic_dec_and_test(&rreq->nr_outstanding)) netfs_rreq_assess(rreq, false); - if (!test_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags)) - break; - cond_resched(); - } + + trace_netfs_rreq(rreq, netfs_rreq_trace_wait_ip); + wait_on_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS, + TASK_UNINTERRUPTIBLE); ret = rreq->error; if (ret == 0 && rreq->submitted < rreq->len) { trace_netfs_failure(rreq, NULL, ret, netfs_fail_short_read); ret = -EIO; } - netfs_put_request(rreq, false, netfs_rreq_trace_put_hold); } else { /* If we decrement nr_outstanding to 0, the ref belongs to us. */ if (atomic_dec_and_test(&rreq->nr_outstanding)) diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h index 4ea4e34d279f..6daadf2aac8a 100644 --- a/include/trace/events/netfs.h +++ b/include/trace/events/netfs.h @@ -34,7 +34,9 @@ EM(netfs_rreq_trace_free, "FREE ") \ EM(netfs_rreq_trace_resubmit, "RESUBMT") \ EM(netfs_rreq_trace_unlock, "UNLOCK ") \ - E_(netfs_rreq_trace_unmark, "UNMARK ") + EM(netfs_rreq_trace_unmark, "UNMARK ") \ + EM(netfs_rreq_trace_wait_ip, "WAIT-IP") \ + E_(netfs_rreq_trace_wake_ip, "WAKE-IP") #define netfs_sreq_sources \ EM(NETFS_FILL_WITH_ZEROES, "ZERO") \ @@ -65,14 +67,13 @@ E_(netfs_fail_prepare_write, "prep-write") #define netfs_rreq_ref_traces \ - EM(netfs_rreq_trace_get_hold, "GET HOLD ") \ + EM(netfs_rreq_trace_get_for_outstanding,"GET OUTSTND") \ EM(netfs_rreq_trace_get_subreq, "GET SUBREQ ") \ EM(netfs_rreq_trace_put_complete, "PUT COMPLT ") \ EM(netfs_rreq_trace_put_discard, "PUT DISCARD") \ EM(netfs_rreq_trace_put_failed, "PUT FAILED ") \ - EM(netfs_rreq_trace_put_hold, "PUT HOLD ") \ + EM(netfs_rreq_trace_put_return, "PUT RETURN ") \ EM(netfs_rreq_trace_put_subreq, "PUT SUBREQ ") \ - EM(netfs_rreq_trace_put_zero_len, "PUT ZEROLEN") \ E_(netfs_rreq_trace_new, "NEW ") #define netfs_sreq_ref_traces \