From nobody Tue Feb 10 00:57:46 2026 Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9FA53763EA; Tue, 26 Mar 2024 13:42:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711460544; cv=none; b=nO4cPLARw12jweGWmil8nGMtZm6enCrw3SXUEOogt2MK+1daBs5ppinqE9ImBJKysqdFQdtoRjhXKUrHKekErhWuhNUCeOLjtc/fxGjRaZAVtc5bxQTXlwNUNrVtXSxJgeKh7rOdQ3uOQAaYYZWk20kjxlpXyORbtxg88gpCljM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711460544; c=relaxed/simple; bh=ACWwNC11SBuRtxRdJI4E8zgSXRpzLp99IRIbOoj2qco=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Yn+vzbHTwrY+kpNo7t5P7EKnHwoEatuYo7pQRz+9bz1/6igfSVtggqiueZeFEvQVGm7fh/nLNFxELB1saeyoBM2vAmCvXf+JAFGMndBIBllm+mIHGmEGjjomEqvWJzAum+rdje959SobX0dwWE15i+SPENyB5zpdvTfuMqwUtbs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.235]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4V3rZV1TSsz4f3mHL; Tue, 26 Mar 2024 21:42:10 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.112]) by mail.maildlp.com (Postfix) with ESMTP id 507B61A0B1E; Tue, 26 Mar 2024 21:42:18 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP1 (Coremail) with SMTP id cCh0CgCHowy00AJmmQiSIA--.63567S3; Tue, 26 Mar 2024 21:42:16 +0800 (CST) From: Kemeng Shi To: tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Cc: jack@suse.cz, ojaswin@linux.ibm.com, ritesh.list@gmail.com Subject: [PATCH 1/5] ext4: keep "prefetch_grp" and "nr" consistent Date: Wed, 27 Mar 2024 05:38:19 +0800 Message-Id: <20240326213823.528302-2-shikemeng@huaweicloud.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20240326213823.528302-1-shikemeng@huaweicloud.com> References: <20240326213823.528302-1-shikemeng@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: cCh0CgCHowy00AJmmQiSIA--.63567S3 X-Coremail-Antispam: 1UD129KBjvJXoW7Cr1Uur48urWfuFyfWw1rJFb_yoW8Jw48pr 9akrW7Cw43Zr1UAayUG3Z0gw1kGw40gw12qFyIk34qqa47ZryfGFsFyr4ruFWUZF47AFy3 Cr9Iya48WF1UWa7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBjb4IE77IF4wAFF20E14v26r4j6ryUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M280x2IEY4vEnII2IxkI6r1a6r45M2 8IrcIa0xkI8VA2jI8067AKxVWUGwA2048vs2IY020Ec7CjxVAFwI0_JFI_Gr1l8cAvFVAK 0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4 x0Y4vE2Ix0cI8IcVCY1x0267AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2 z4x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4 xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v2 6r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwCF04k20xvY0x0EwI xGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480 Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vIr41lIxAIcVC0I7 IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k2 6cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxV AFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07jIc_fUUUUU= X-CM-SenderInfo: 5vklyvpphqwq5kxd4v5lfo033gof0z/ Content-Type: text/plain; charset="utf-8" Keep "prefetch_grp" and "nr" consistent to avoid to call ext4_mb_prefetch_fini with non-prefetched groups. When we step into next criteria, "prefetch_grp" is set to prefetch start of new criteria while "nr" is number of the prefetched group in previous criteria. If previous criteria and next criteria are both inexpensive (< CR_GOAL_LEN_SLOW) and prefetch_ios reachs sbi->s_mb_prefetch_limit in previous criteria, "prefetch_grp" and "nr" will be inconsistent and may introduce unexpected cost to do ext4_mb_init_group for non-prefetched groups. Reset "nr" to 0 when we reset "prefetch_grp" to start of prefech in next criteria to ensure "prefetch_grp" and "nr" are consistent. Signed-off-by: Kemeng Shi Reviewed-by: Jan Kara Reviewed-by: Ojaswin Mujoo --- fs/ext4/mballoc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 12b3f196010b..a61fc52956b2 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2856,6 +2856,7 @@ ext4_mb_regular_allocator(struct ext4_allocation_cont= ext *ac) group =3D ac->ac_g_ex.fe_group; ac->ac_groups_linear_remaining =3D sbi->s_mb_max_linear_groups; prefetch_grp =3D group; + nr =3D 0; =20 for (i =3D 0, new_cr =3D cr; i < ngroups; i++, ext4_mb_choose_next_group(ac, &new_cr, &group, ngroups)) { --=20 2.30.0