From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D3ED6C433E9 for ; Mon, 15 Mar 2021 17:38:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9E5B664F3F for ; Mon, 15 Mar 2021 17:38:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232110AbhCORhq (ORCPT ); Mon, 15 Mar 2021 13:37:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36030 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237255AbhCORha (ORCPT ); Mon, 15 Mar 2021 13:37:30 -0400 Received: from mail-pj1-x102b.google.com (mail-pj1-x102b.google.com [IPv6:2607:f8b0:4864:20::102b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 21049C06174A for ; Mon, 15 Mar 2021 10:37:30 -0700 (PDT) Received: by mail-pj1-x102b.google.com with SMTP id kr3-20020a17090b4903b02900c096fc01deso15177797pjb.4 for ; Mon, 15 Mar 2021 10:37:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Rm6iff/Xns9Fjjp2zg4s4LGlY03vmdwWCtYKtxgtvxM=; b=DgPmnFejlSRyfj7gtuRUmmhGjSLPrRBlRfX8iOCirobfLSw4PsuxelDsiJ7HLWWjjo vlxgrITXntaJYeu0qtT/OgYBhdIQKx7mE6b5oCK3io87LPzYdWlX3RiJhl5kshnoQ5MI eaF6XPCkdUxDCH6f55icZF+DejK1wh+S81zJwEuI1uOCtWrWjb7fahqchY8bgozE0mbl giuZxsNknt1WndQqenSkec+dO+D6DC5n246bicd+W82oB6oPwnaVPlbe5Yga7fuBbvjI iMeVMw1U10Hnw3QYxrLQyhWKDyemwcr+swsIBMMxFxuAqLvFSOnXvA1p//6ODF4hf5hb G1kA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Rm6iff/Xns9Fjjp2zg4s4LGlY03vmdwWCtYKtxgtvxM=; b=QwUJE5+vSyNn+ROQstydz92CZnPPL/PPgFn8VyyLB1j+FosyXQz/u2vdxzrugmREyB 1q/CWzryAtvmxYUXEhVchk78pUXm2BLEM+6yFNkhiK4oV3nzE1T+DxDbRmPBdpKu7KgH ttEqnkLRclQAO6X1QqjKHyG7/BFtcB9DVuGwf8NoMw+Ju/+PR31MrroQf8gMNjQ57gIx Mxc+2FgGcwdKUGg5L+ZWTqrd2qs7/2vu06RTo/McbOHvAfDfV4y2ZPp7n/sbyA8hEha6 cICU3/GWeYcAIj2Y2EpibbCE8Bi7zDwGFBPLPq3zIII7/V3DvJAb1CiASK7TSfy+9gV4 Eh6g== X-Gm-Message-State: AOAM5329HxSt7ho3VgZu01siu7nj642svtn3MIm9sGKQMKY6NDil+Vm8 SLuYx1PDPipkTOVzNKxARolROURQjyI= X-Google-Smtp-Source: ABdhPJwLL360RbuqTDoncMVJqPP9pP8JLjVW50pmRnQfjHpoJtjkq66CeJ7aU+SDW1macTYjimdpqQ== X-Received: by 2002:a17:90b:ecc:: with SMTP id gz12mr174919pjb.79.1615829849335; Mon, 15 Mar 2021 10:37:29 -0700 (PDT) Received: from harshads-520.kir.corp.google.com ([2620:15c:17:10:1025:7e5a:33cc:4e9c]) by smtp.googlemail.com with ESMTPSA id p190sm13520178pga.78.2021.03.15.10.37.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Mar 2021 10:37:28 -0700 (PDT) From: Harshad Shirwadkar To: linux-ext4@vger.kernel.org Cc: tytso@mit.edu, Harshad Shirwadkar , Andreas Dilger Subject: [PATCH v4 1/6] ext4: drop s_mb_bal_lock and convert protected fields to atomic Date: Mon, 15 Mar 2021 10:37:11 -0700 Message-Id: <20210315173716.360726-2-harshadshirwadkar@gmail.com> X-Mailer: git-send-email 2.31.0.rc2.261.g7f71774620-goog In-Reply-To: <20210315173716.360726-1-harshadshirwadkar@gmail.com> References: <20210315173716.360726-1-harshadshirwadkar@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org s_mb_buddies_generated gets used later in this patch series to determine if the cr 0 and cr 1 optimziations should be performed or not. Currently, s_mb_buddies_generated is protected under a spin_lock. In the allocation path, it is better if we don't depend on the lock and instead read the value atomically. In order to do that, we drop s_bal_lock altogether and we convert the only two protected fields by it s_mb_buddies_generated and s_mb_generation_time to atomic type. Signed-off-by: Harshad Shirwadkar Reviewed-by: Andreas Dilger --- fs/ext4/ext4.h | 5 ++--- fs/ext4/mballoc.c | 13 +++++-------- 2 files changed, 7 insertions(+), 11 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 2866d249f3d2..cb0724b87d54 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1552,9 +1552,8 @@ struct ext4_sb_info { atomic_t s_bal_goals; /* goal hits */ atomic_t s_bal_breaks; /* too long searches */ atomic_t s_bal_2orders; /* 2^order hits */ - spinlock_t s_bal_lock; - unsigned long s_mb_buddies_generated; - unsigned long long s_mb_generation_time; + atomic_t s_mb_buddies_generated; /* number of buddies generated */ + atomic64_t s_mb_generation_time; atomic_t s_mb_lost_chunks; atomic_t s_mb_preallocated; atomic_t s_mb_discarded; diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 99bf091fee10..07b78a3cc421 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -816,10 +816,8 @@ void ext4_mb_generate_buddy(struct super_block *sb, clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state)); period = get_cycles() - period; - spin_lock(&sbi->s_bal_lock); - sbi->s_mb_buddies_generated++; - sbi->s_mb_generation_time += period; - spin_unlock(&sbi->s_bal_lock); + atomic_inc(&sbi->s_mb_buddies_generated); + atomic64_add(period, &sbi->s_mb_generation_time); } /* The buddy information is attached the buddy cache inode @@ -2843,7 +2841,6 @@ int ext4_mb_init(struct super_block *sb) } while (i <= sb->s_blocksize_bits + 1); spin_lock_init(&sbi->s_md_lock); - spin_lock_init(&sbi->s_bal_lock); sbi->s_mb_free_pending = 0; INIT_LIST_HEAD(&sbi->s_freed_data_list); @@ -2979,9 +2976,9 @@ int ext4_mb_release(struct super_block *sb) atomic_read(&sbi->s_bal_breaks), atomic_read(&sbi->s_mb_lost_chunks)); ext4_msg(sb, KERN_INFO, - "mballoc: %lu generated and it took %Lu", - sbi->s_mb_buddies_generated, - sbi->s_mb_generation_time); + "mballoc: %u generated and it took %llu", + atomic_read(&sbi->s_mb_buddies_generated), + atomic64_read(&sbi->s_mb_generation_time)); ext4_msg(sb, KERN_INFO, "mballoc: %u preallocated, %u discarded", atomic_read(&sbi->s_mb_preallocated), -- 2.31.0.rc2.261.g7f71774620-goog