From patchwork Tue Feb 9 20:28:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: harshad shirwadkar X-Patchwork-Id: 1438681 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-ext4-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=i1unExR5; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4DZw0T39Zdz9sCD for ; Wed, 10 Feb 2021 07:46:17 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233974AbhBIUpM (ORCPT ); Tue, 9 Feb 2021 15:45:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233826AbhBIUjr (ORCPT ); Tue, 9 Feb 2021 15:39:47 -0500 Received: from mail-pf1-x42f.google.com (mail-pf1-x42f.google.com [IPv6:2607:f8b0:4864:20::42f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B152C0698D4 for ; Tue, 9 Feb 2021 12:29:06 -0800 (PST) Received: by mail-pf1-x42f.google.com with SMTP id z6so3514202pfq.0 for ; Tue, 09 Feb 2021 12:29:06 -0800 (PST) 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=r6gXc36Fb7rev0oeIRbVuSomePZlN/Rh1wSk7zuJJl8=; b=i1unExR5mEXn0h9u/DX3vamDMNXG0KMzY1P5es/Z8TRFp43c4kJ7nLKE9oxo8UjEns uk+e3XS+fdwiLVQtEa39cbcjF5W2RXlgc9Bdchr3MDVD4c2vzAFU+Wo/xSn01NJrORS3 3LiGTE/8/yvftMc3ZXzHMxTUMGpvMCTxcMkWxHSZFU7NvbdKHNFwTzFnPFIYTHWSyMSu A3jZaglHRxYlpP3Rfo+xeQfETXFNATVsKLXFBVfC7gMl4RFyf/EVq4c40uKUl4Vvyqmd vzw1lXQTop9nG3LqOdtpk86FTcdFT5mr3H4pHTDcbHdm/0dxJcg2kcv5oKk2lzyix8VM UwNg== 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=r6gXc36Fb7rev0oeIRbVuSomePZlN/Rh1wSk7zuJJl8=; b=nIyEIzlARLuUgdB4gRdYZfuROePWvWnwebBZgqfzZUeZulBueyQDTdaAJsjPzIFlFM o9y3Br5TTnZwrT0iAsPw3X0NkkPpmwjxsfJfRs/jYFAKefdS8J2+oNDoM9jdfK0z8zya h28I6K0D43Phdv4Uer4aAEd+/hW9/gMoDcz3FYEmhEBLOuEsXJNCSNhMODYNSgpWIRwE eOvHr8bW+9PZNvE7uMhsTRN2NYZWLdZdwpD+BIN9eynAJyOaYq9uOuretBkifjo5TS3+ FYhdYtieemPl9SYE0QFNCN1gpFuJD/Y3wnyNscQCRvddHYLwOhUu3maz455y9j+1xHOB x57Q== X-Gm-Message-State: AOAM5323MVHanUy2J0qNc44t3z23B9JLj7v0bBB+mibCJkokcDhtgaSd 2WRtrZwxLlT8sTfbnSnWXQcVkIBnRk8= X-Google-Smtp-Source: ABdhPJxmdpAuT5XD5z5Pat2zTGL+viZ/MBhLeMr8c8zcRTalYqfDHFR3MUUULXLPP8n8w3Xw7dsggw== X-Received: by 2002:a63:4a49:: with SMTP id j9mr24270712pgl.197.1612902545937; Tue, 09 Feb 2021 12:29:05 -0800 (PST) Received: from harshads-520.kir.corp.google.com ([2620:15c:17:10:1d7c:b2d9:c196:949c]) by smtp.googlemail.com with ESMTPSA id p12sm3325827pju.35.2021.02.09.12.29.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Feb 2021 12:29:05 -0800 (PST) From: Harshad Shirwadkar To: linux-ext4@vger.kernel.org Cc: tytso@mit.edu, bzzz@whamcloud.com, artem.blagodarenko@gmail.com, sihara@ddn.com, adilger@dilger.ca, Harshad Shirwadkar Subject: [PATCH v2 1/5] ext4: drop s_mb_bal_lock and convert protected fields to atomic Date: Tue, 9 Feb 2021 12:28:53 -0800 Message-Id: <20210209202857.4185846-2-harshadshirwadkar@gmail.com> X-Mailer: git-send-email 2.30.0.478.g8a0d178c01-goog In-Reply-To: <20210209202857.4185846-1-harshadshirwadkar@gmail.com> References: <20210209202857.4185846-1-harshadshirwadkar@gmail.com> MIME-Version: 1.0 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 64f25ea2fa7a..6dd127942208 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),