From patchwork Tue Nov 22 13:42:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Christoph_B=C3=B6hmwalder?= X-Patchwork-Id: 24381 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:f944:0:0:0:0:0 with SMTP id q4csp2206954wrr; Tue, 22 Nov 2022 05:46:15 -0800 (PST) X-Google-Smtp-Source: AA0mqf5xWzMjJTeKF/J3oFxTN0MZnkBod+ZYq82kEo8acKjJKq5gtMnTFUoxQO7NbByd06myYh4m X-Received: by 2002:a17:906:3ac1:b0:78d:36d8:1814 with SMTP id z1-20020a1709063ac100b0078d36d81814mr19177421ejd.99.1669124775757; Tue, 22 Nov 2022 05:46:15 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1669124775; cv=none; d=google.com; s=arc-20160816; b=kGs/ER9Qpkr/ls7CqtnM4mKhRtZqd4xDq68VE8IztcBU6SE/TYKOkEny1YpFR7KWXz 5L6tUOWAuF/CV7pl/r2XGIo6jcyI3KOvC2WkevDgy/mKkgl2oZbdSDdxKjoNOXwaSthG dYsk6KHx/10e6w1fjXGFWf8ml8SjUopsucEM5t40lbOU010OqDmuAxDxE38MV6GFEm+9 dW7qPfA6Po1DPbGpsU3zcf/QuCrBJdpCgosGW/ccgFMAFrOxiyJpG5kiRjSWr6M5DBQQ 5IZrpfT6hUGImoD6iyUDRKrKWm1QuVlWdP9goLzmEgBJ/p8F3eNPDrItyNYyxAkKsJ+0 iMTA== 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=KF3CZXuQwHBE4nlGvTbysgbhQTbuB3zQD8B/JpHaOzg=; b=AyBDATioxrNz3atcgshXDqYhSXCy91Rr0IlbrxZkLGp7f4szY9IOP/oxaE/SzlBac4 NleoipAonBnk6WD29mqZGW4+24WhBlQHxhCh9JuhUo+a8uWa7sIgADwKrqqMoeBmGADq 5+oaXU6Kda1oQ8sfq2yDh6rr5CWKP23hcxmE01huTTC1NXVSd/RPEOiGqZUD5Bm9D1o2 sGOgBieagMOarSrKArTfpW9ChUR77qsPJEsIXQnEhMEZcIaW+eOyXPm2bjP61WUXVjPe icBEzkSfAPtOnM/EzaUgwu/gzbFWZk55RNiHvTeoJcKPWkwcXJYIV3YSKsab6HLLC7av vMNw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linbit-com.20210112.gappssmtp.com header.s=20210112 header.b=Cbx7zn11; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id hg2-20020a1709072cc200b0078dec48d442si12269059ejc.680.2022.11.22.05.45.51; Tue, 22 Nov 2022 05:46:15 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linbit-com.20210112.gappssmtp.com header.s=20210112 header.b=Cbx7zn11; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232653AbiKVNnT (ORCPT + 99 others); Tue, 22 Nov 2022 08:43:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41684 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232410AbiKVNnN (ORCPT ); Tue, 22 Nov 2022 08:43:13 -0500 Received: from mail-wr1-x430.google.com (mail-wr1-x430.google.com [IPv6:2a00:1450:4864:20::430]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C387C32B8C for ; Tue, 22 Nov 2022 05:43:12 -0800 (PST) Received: by mail-wr1-x430.google.com with SMTP id z4so10180478wrr.3 for ; Tue, 22 Nov 2022 05:43:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linbit-com.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=KF3CZXuQwHBE4nlGvTbysgbhQTbuB3zQD8B/JpHaOzg=; b=Cbx7zn11EQehMM+81fn1VToCqdvNlnjLXq36xiSGojRY4l/t8KeOuqmgNPSFjh09S4 f/4yjE67gsK/CFRgOSP0pL/8N+IHCAR0NVN9MCiq1aNMEqps0/lzg9/FIfgMCzHY/azH tqMu57sNswPfw1RKchHVhiLaxK1POke5vckhvWHje6LHsMcqhWn7Qd7NxidBNcNOpgOn J8DLQ2mg60qgLy351jlgSEPilGpsEhJasu9kc4rJHZW8aaYIWJdM9npuoGPfWj6+SXM2 KcpGLp/W0SkFnOjbgqahbRrxXAQ+KUu0be+Iklv7EALyEIfLxDQOPJYz0wQCtZbPSqN6 0nbg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=KF3CZXuQwHBE4nlGvTbysgbhQTbuB3zQD8B/JpHaOzg=; b=p5bPcodWgZthpIM9m2rDeNr5EIpuYw0sop0z1AQlDaUTF/8RSfLQhm551ks7IfaB80 m8w50iy0DxzKwEa13BOte5YU8jMcDHmaLJuHvtqSHZU7HT5j/5MAZWoNNWmBWLonfD7v NY6qyB7byoAzJCmL2dew7G50vb5jL6Cw0zBnlxOty9IYEwq7DhjpvCOiEQQF81KpwQaE RUaAaxX+ALTeHq0hFOATWfFHj4c/Xz2Zt5byochYKM71uHwbiKVenv9b0r3Yn4kJGzhB XL7DSN8yRG8E7s3HdxQ6coPKaHFNE1lL6yrkkfoqw5JI503z915X3nNRfkbMoMxD+VMB q2Mw== X-Gm-Message-State: ANoB5pmlw03R2wJoKHIJgM8WdPb+i0g7iv6Odec8hzjU/63sdn4EL5RQ k1QcjnmTZLe2BPy2QzpLRrbCcUvbSLB1EXJm X-Received: by 2002:a05:6000:1192:b0:241:e7a6:9135 with SMTP id g18-20020a056000119200b00241e7a69135mr661925wrx.641.1669124591378; Tue, 22 Nov 2022 05:43:11 -0800 (PST) Received: from localhost.localdomain (h082218028181.host.wavenet.at. [82.218.28.181]) by smtp.gmail.com with ESMTPSA id p6-20020a1c5446000000b003b47e75b401sm21437729wmi.37.2022.11.22.05.43.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Nov 2022 05:43:10 -0800 (PST) From: =?utf-8?q?Christoph_B=C3=B6hmwalder?= To: Jens Axboe Cc: drbd-dev@lists.linbit.com, linux-kernel@vger.kernel.org, Lars Ellenberg , Philipp Reisner , linux-block@vger.kernel.org, =?utf-8?q?Christoph_B=C3=B6hmwalder?= Subject: [PATCH 1/4] lru_cache: use atomic operations when accessing lc->flags, always Date: Tue, 22 Nov 2022 14:42:58 +0100 Message-Id: <20221122134301.69258-2-christoph.boehmwalder@linbit.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221122134301.69258-1-christoph.boehmwalder@linbit.com> References: <20221122134301.69258-1-christoph.boehmwalder@linbit.com> MIME-Version: 1.0 X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1750204180751438803?= X-GMAIL-MSGID: =?utf-8?q?1750204180751438803?= From: Lars Ellenberg Or, depending on the way locking is implemented at the call sites, some updates could be lost (has not been observed). Signed-off-by: Lars Ellenberg Signed-off-by: Christoph Böhmwalder --- lib/lru_cache.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/lib/lru_cache.c b/lib/lru_cache.c index dc35464216d3..fec899386238 100644 --- a/lib/lru_cache.c +++ b/lib/lru_cache.c @@ -364,7 +364,7 @@ static struct lc_element *__lc_get(struct lru_cache *lc, unsigned int enr, unsig struct lc_element *e; PARANOIA_ENTRY(); - if (lc->flags & LC_STARVING) { + if (test_bit(__LC_STARVING, &lc->flags)) { ++lc->starving; RETURN(NULL); } @@ -417,7 +417,7 @@ static struct lc_element *__lc_get(struct lru_cache *lc, unsigned int enr, unsig * the LRU element, we have to wait ... */ if (!lc_unused_element_available(lc)) { - __set_bit(__LC_STARVING, &lc->flags); + set_bit(__LC_STARVING, &lc->flags); RETURN(NULL); }