From nobody Sun Feb 8 23:26:06 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 From nobody Sun Feb 8 23:26:06 2026 Received: from dggsgout12.his.huawei.com (unknown [45.249.212.56]) (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 E1F4E126F30; Tue, 26 Mar 2024 13:42:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711460544; cv=none; b=kp8ndJ94dgnRtLh0lYDnuYZaLI4S6LpPApDDvGutC/F/bG/oW0z8id63nRzARIx2VmXYCjRQuy7MB5TwZDUI5aU3apNWOJmtHzAMcOAQjzc8AvSyHJ3r2RAZIDOmjGH/RKGTqCup9V/3JQMkaO4kNlM5w4cX3/B/KUyc5YQTwSQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711460544; c=relaxed/simple; bh=43XEMOYK3ZhQsU0mW9vnq/Hdvqc0TOl/lJ/ZjN8LKxE=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=ozCxmopqkqDPyD2wN+dHXFha7OBtB6Jym++jCzjCa/xvIYkYB2c+P41yocXOKMBcHUD5oLNJDe6PeBkaypueKYBZu4zwUjYIPBLVSDnSPA37y4iXdvtSMkrUT1XKWWAz8eg6mgV0XLsdoHo/koXf1mIegAf3YyOYP7cSEprkRP4= 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=45.249.212.56 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 [172.19.163.216]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4V3rZX35QRz4f3jY2; Tue, 26 Mar 2024 21:42:12 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.112]) by mail.maildlp.com (Postfix) with ESMTP id 9DCBB1A019F; 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--.63567S4; Tue, 26 Mar 2024 21:42:18 +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 2/5] ext4: add test_mb_mark_used_cost to estimate cost of mb_mark_used Date: Wed, 27 Mar 2024 05:38:20 +0800 Message-Id: <20240326213823.528302-3-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--.63567S4 X-Coremail-Antispam: 1UD129KBjvJXoWxCrW7ur1rJF4DtF1xGF4DArb_yoW5Kw48pa yqkFnYkr45Zwsa9w4fC3s7Zw1Sgw1kZr48JryfWF9avFW7Jas3CFn5KFy5GrW0qr4kXrn0 vFyq9ry7G397CF7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBjb4IE77IF4wAFF20E14v26ryj6rWUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M280x2IEY4vEnII2IxkI6r1a6r45M2 8IrcIa0xkI8VA2jI8067AKxVWUXwA2048vs2IY020Ec7CjxVAFwI0_Gr0_Xr1l8cAvFVAK 0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4 x0Y4vE2Ix0cI8IcVCY1x0267AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2 z4x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4 xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v2 6r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwCF04k20xvY0x0EwI xGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480 Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vIr41lIxAIcVC0I7 IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k2 6cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxV AFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07jhpndUUUUU= X-CM-SenderInfo: 5vklyvpphqwq5kxd4v5lfo033gof0z/ Content-Type: text/plain; charset="utf-8" Add test_mb_mark_used_cost to estimate runtime of mb_mark_used. Result of unit test is as following: $ ./tools/testing/kunit/kunit.py run --kunitconfig=3Dfs/ext4/.kunitconfig -= -raw_output ... # Subtest: test_mb_mark_used_cost # test_mb_mark_used_cost: costed jiffies 311 ok 1 block_bits=3D10 cluster_bits=3D3 blocks_per_group=3D8192 group= _count=3D4 desc_size=3D64 # test_mb_mark_used_cost: costed jiffies 304 ok 2 block_bits=3D12 cluster_bits=3D3 blocks_per_group=3D8192 group= _count=3D4 desc_size=3D64 ok 3 block_bits=3D16 cluster_bits=3D3 blocks_per_group=3D8192 group= _count=3D4 desc_size=3D64 # SKIP blocksize exceeds pagesize # test_mb_mark_used_cost.speed: slow # test_mb_mark_used_cost: pass:2 fail:0 skip:1 total:3 ok 7 test_mb_mark_used_cost ... Signed-off-by: Kemeng Shi --- fs/ext4/mballoc-test.c | 56 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) diff --git a/fs/ext4/mballoc-test.c b/fs/ext4/mballoc-test.c index 044ca5238f41..cb1a551f9596 100644 --- a/fs/ext4/mballoc-test.c +++ b/fs/ext4/mballoc-test.c @@ -859,6 +859,56 @@ static void test_mb_free_blocks(struct kunit *test) ext4_mb_unload_buddy(&e4b); } =20 +#define COUNT_FOR_ESTIMATE 1000000 +static void test_mb_mark_used_cost(struct kunit *test) +{ + struct ext4_buddy e4b; + struct super_block *sb =3D (struct super_block *)test->priv; + struct ext4_free_extent ex; + int ret; + struct test_range ranges[TEST_RANGE_COUNT]; + int i, j; + unsigned long start, end, all =3D 0; + + /* buddy cache assumes that each page contains at least one block */ + if (sb->s_blocksize > PAGE_SIZE) + kunit_skip(test, "blocksize exceeds pagesize"); + + ret =3D ext4_mb_load_buddy(sb, TEST_GOAL_GROUP, &e4b); + KUNIT_ASSERT_EQ(test, ret, 0); + + ex.fe_group =3D TEST_GOAL_GROUP; + for (j =3D 0; j < COUNT_FOR_ESTIMATE; j++) { + mbt_generate_test_ranges(sb, ranges, TEST_RANGE_COUNT); + start =3D jiffies; + for (i =3D 0; i < TEST_RANGE_COUNT; i++) { + if (ranges[i].len =3D=3D 0) + continue; + + ex.fe_start =3D ranges[i].start; + ex.fe_len =3D ranges[i].len; + ext4_lock_group(sb, TEST_GOAL_GROUP); + mb_mark_used(&e4b, &ex); + ext4_unlock_group(sb, TEST_GOAL_GROUP); + } + end =3D jiffies; + all +=3D (end - start); + + for (i =3D 0; i < TEST_RANGE_COUNT; i++) { + if (ranges[i].len =3D=3D 0) + continue; + + ext4_lock_group(sb, TEST_GOAL_GROUP); + mb_free_blocks(NULL, &e4b, ranges[i].start, + ranges[i].len); + ext4_unlock_group(sb, TEST_GOAL_GROUP); + } + } + + kunit_info(test, "costed jiffies %lu\n", all); + ext4_mb_unload_buddy(&e4b); +} + static const struct mbt_ext4_block_layout mbt_test_layouts[] =3D { { .blocksize_bits =3D 10, @@ -894,6 +944,10 @@ static void mbt_show_layout(const struct mbt_ext4_bloc= k_layout *layout, } KUNIT_ARRAY_PARAM(mbt_layouts, mbt_test_layouts, mbt_show_layout); =20 +static const struct kunit_attributes slow_attr =3D { + .speed =3D KUNIT_SPEED_SLOW, +}; + static struct kunit_case mbt_test_cases[] =3D { KUNIT_CASE_PARAM(test_new_blocks_simple, mbt_layouts_gen_params), KUNIT_CASE_PARAM(test_free_blocks_simple, mbt_layouts_gen_params), @@ -901,6 +955,8 @@ static struct kunit_case mbt_test_cases[] =3D { KUNIT_CASE_PARAM(test_mb_mark_used, mbt_layouts_gen_params), KUNIT_CASE_PARAM(test_mb_free_blocks, mbt_layouts_gen_params), KUNIT_CASE_PARAM(test_mark_diskspace_used, mbt_layouts_gen_params), + KUNIT_CASE_PARAM_ATTR(test_mb_mark_used_cost, mbt_layouts_gen_params, + slow_attr), {} }; =20 --=20 2.30.0 From nobody Sun Feb 8 23:26:06 2026 Received: from dggsgout12.his.huawei.com (unknown [45.249.212.56]) (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 5149B1272C8; Tue, 26 Mar 2024 13:42:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.235]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4V3rZX5MtZz4f3jcn; Tue, 26 Mar 2024 21:42:12 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.112]) by mail.maildlp.com (Postfix) with ESMTP id EABC51A0B26; 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--.63567S5; Tue, 26 Mar 2024 21:42:18 +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 3/5] ext4: call ext4_mb_mark_free_simple in mb_mark_used to clear bits Date: Wed, 27 Mar 2024 05:38:21 +0800 Message-Id: <20240326213823.528302-4-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--.63567S5 X-Coremail-Antispam: 1UD129KBjvJXoWxAFWxWw4fZF1fuF1furWfZrb_yoWrWr17pF W3ZrWfGr40vwn29F4UG3WjgF1F93y8ta45Jas3Ww1rWwnxJryFvFn5KF13Z3WvvrZ3XFyF yr4UuFy3Krs7KFDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBjb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M280x2IEY4vEnII2IxkI6r1a6r45M2 8IrcIa0xkI8VA2jI8067AKxVWUWwA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK 0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4 x0Y4vE2Ix0cI8IcVCY1x0267AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2 z4x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4 xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v2 6r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwCF04k20xvY0x0EwI xGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480 Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vIr41lIxAIcVC0I7 IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k2 6cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxV AFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07j2FAJUUUUU= X-CM-SenderInfo: 5vklyvpphqwq5kxd4v5lfo033gof0z/ Content-Type: text/plain; charset="utf-8" Function ext4_mb_mark_free_simple could search order for bit clearing in O(1) cost while mb_mark_used will search order in O(distance from chunk order to target order) and introduce unnecessary bit flips. Consider we have 4 continuous free bits and going to mark bit 0-2 inuse. initial state of buddy bitmap: order 2 | 0 | order 1 | 1 | 1 | order 0 | 1 | 1 | 1 | 1 | mark whole chunk inuse order 2 | 1 | order 1 | 1 | 1 | order 0 | 1 | 1 | 1 | 1 | split chunk to order 1 order 2 | 1 | order 1 | 0 | 0 | order 0 | 1 | 1 | 1 | 1 | set the first bit in order 1 to mark bit 0-1 inuse set the second bit in order 1 for split order 2 | 1 | order 1 | 1 | 1 | order 0 | 1 | 1 | 1 | 1 | step 3: split the second bit in order 1 to order 0 order 2 | 1 | order 1 | 1 | 1 | order 0 | 1 | 1 | 0 | 0 | step 4: set the third bit in order 0 to mark bit 2 inuse. order 2 | 1 | order 1 | 1 | 1 | order 0 | 1 | 1 | 1 | 0 | There are two unnecessary splits and three unnecessary bit flips. With ext4_mb_mark_free_simple, we will clear the 4th bit in order 0 with O(1) search and no extra bit flip. The cost estimated by test_mb_mark_used_cost is as following: Before (three runs of test): # test_mb_mark_used_cost: costed jiffies 311 # test_mb_mark_used_cost: costed jiffies 304 # test_mb_mark_used_cost: costed jiffies 305 # test_mb_mark_used_cost: costed jiffies 323 # test_mb_mark_used_cost: costed jiffies 317 # test_mb_mark_used_cost: costed jiffies 317 After (three runs of test): # test_mb_mark_used_cost: costed jiffies 166 # test_mb_mark_used_cost: costed jiffies 152 # test_mb_mark_used_cost: costed jiffies 159 # test_mb_mark_used_cost: costed jiffies 138 # test_mb_mark_used_cost: costed jiffies 149 Signed-off-by: Kemeng Shi --- fs/ext4/mballoc.c | 37 ++++++++++++++++++++----------------- 1 file changed, 20 insertions(+), 17 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index a61fc52956b2..62d468379722 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2040,13 +2040,12 @@ static int mb_mark_used(struct ext4_buddy *e4b, str= uct ext4_free_extent *ex) int ord; int mlen =3D 0; int max =3D 0; - int cur; int start =3D ex->fe_start; int len =3D ex->fe_len; unsigned ret =3D 0; int len0 =3D len; void *buddy; - bool split =3D false; + int ord_start, ord_end; =20 BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3)); BUG_ON(e4b->bd_group !=3D ex->fe_group); @@ -2071,16 +2070,12 @@ static int mb_mark_used(struct ext4_buddy *e4b, str= uct ext4_free_extent *ex) =20 /* let's maintain buddy itself */ while (len) { - if (!split) - ord =3D mb_find_order_for_block(e4b, start); + ord =3D mb_find_order_for_block(e4b, start); =20 if (((start >> ord) << ord) =3D=3D start && len >=3D (1 << ord)) { /* the whole chunk may be allocated at once! */ mlen =3D 1 << ord; - if (!split) - buddy =3D mb_find_buddy(e4b, ord, &max); - else - split =3D false; + buddy =3D mb_find_buddy(e4b, ord, &max); BUG_ON((start >> ord) >=3D max); mb_set_bit(start >> ord, buddy); e4b->bd_info->bb_counters[ord]--; @@ -2094,20 +2089,28 @@ static int mb_mark_used(struct ext4_buddy *e4b, str= uct ext4_free_extent *ex) if (ret =3D=3D 0) ret =3D len | (ord << 16); =20 - /* we have to split large buddy */ BUG_ON(ord <=3D 0); buddy =3D mb_find_buddy(e4b, ord, &max); mb_set_bit(start >> ord, buddy); e4b->bd_info->bb_counters[ord]--; =20 - ord--; - cur =3D (start >> ord) & ~1U; - buddy =3D mb_find_buddy(e4b, ord, &max); - mb_clear_bit(cur, buddy); - mb_clear_bit(cur + 1, buddy); - e4b->bd_info->bb_counters[ord]++; - e4b->bd_info->bb_counters[ord]++; - split =3D true; + ord_start =3D (start >> ord) << ord; + ord_end =3D ord_start + (1 << ord); + if (start > ord_start) + ext4_mb_mark_free_simple(e4b->bd_sb, e4b->bd_buddy, + ord_start, start - ord_start, + e4b->bd_info); + + if (start + len < ord_end) { + ext4_mb_mark_free_simple(e4b->bd_sb, e4b->bd_buddy, + start + len, + ord_end - (start + len), + e4b->bd_info); + break; + } + + len =3D start + len - ord_end; + start =3D ord_end; } mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info); =20 --=20 2.30.0 From nobody Sun Feb 8 23:26:06 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 87AB4763F1; 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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 [172.19.163.216]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4V3rZW1JH6z4f3mJ2; Tue, 26 Mar 2024 21:42:11 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.112]) by mail.maildlp.com (Postfix) with ESMTP id 4B26C1A01A7; Tue, 26 Mar 2024 21:42:19 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP1 (Coremail) with SMTP id cCh0CgCHowy00AJmmQiSIA--.63567S6; Tue, 26 Mar 2024 21:42:19 +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 4/5] ext4: use correct criteria name instead stale integer number in comment Date: Wed, 27 Mar 2024 05:38:22 +0800 Message-Id: <20240326213823.528302-5-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--.63567S6 X-Coremail-Antispam: 1UD129KBjvJXoWxGryxJw1Dury3Xw13KF4DJwb_yoW5uF4rp3 9ayF18Kw4SgF13u393Ga1jg3W8Gw4I9F1UWryF9w17uFyaqr93tFWDKFW0yFy0vr4rZ3Wr XFy7Xw48CF1S93DanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUB2b4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M280x2IEY4vEnII2IxkI6r1a6r45M2 8IrcIa0xkI8VA2jI8067AKxVWUAVCq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAv FVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJw A2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE 3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr2 1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r106r15McIj6I8E87Iv 67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41l42xK82IYc2 Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s02 6x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMIIYrxkI7VAKI48JMIIF0x vE2Ix0cI8IcVAFwI0_JFI_Gr1lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE 42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6x kF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUxD7aUUUUU X-CM-SenderInfo: 5vklyvpphqwq5kxd4v5lfo033gof0z/ Content-Type: text/plain; charset="utf-8" Use correct criteria name instead stale integer number in comment Signed-off-by: Kemeng Shi Reviewed-by: Ojaswin Mujoo --- fs/ext4/ext4.h | 15 ++++++++++++--- fs/ext4/mballoc.c | 14 ++++++++------ fs/ext4/mballoc.h | 4 ++-- 3 files changed, 22 insertions(+), 11 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 023571f8dd1b..9b90013c59a3 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -213,11 +213,20 @@ enum criteria { #define EXT4_MB_USE_RESERVED 0x2000 /* Do strict check for free blocks while retrying block allocation */ #define EXT4_MB_STRICT_CHECK 0x4000 -/* Large fragment size list lookup succeeded at least once for cr =3D 0 */ +/* + * Large fragment size list lookup succeeded at least once for cr =3D + * CR_POWER2_ALIGNED + */ #define EXT4_MB_CR_POWER2_ALIGNED_OPTIMIZED 0x8000 -/* Avg fragment size rb tree lookup succeeded at least once for cr =3D 1 */ +/* + * Avg fragment size rb tree lookup succeeded at least once for cr =3D + * CR_GOAL_LEN_FAST + */ #define EXT4_MB_CR_GOAL_LEN_FAST_OPTIMIZED 0x00010000 -/* Avg fragment size rb tree lookup succeeded at least once for cr =3D 1.5= */ +/* + * Avg fragment size rb tree lookup succeeded at least once for cr =3D + * CR_BEST_AVAIL_LEN + */ #define EXT4_MB_CR_BEST_AVAIL_LEN_OPTIMIZED 0x00020000 =20 struct ext4_allocation_request { diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 62d468379722..0f8a34513bf6 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -1131,8 +1131,9 @@ static void ext4_mb_choose_next_group(struct ext4_all= ocation_context *ac, ext4_mb_choose_next_group_best_avail(ac, new_cr, group); } else { /* - * TODO: For CR=3D2, we can arrange groups in an rb tree sorted by - * bb_free. But until that happens, we should never come here. + * TODO: For CR=3DCR_GOAL_LEN_SLOW, we can arrange groups in an + * rb tree sorted by bb_free. But until that happens, we should + * never come here. */ WARN_ON(1); } @@ -3444,10 +3445,11 @@ static int ext4_mb_init_backend(struct super_block = *sb) } if (sbi->s_mb_prefetch > ext4_get_groups_count(sb)) sbi->s_mb_prefetch =3D ext4_get_groups_count(sb); - /* now many real IOs to prefetch within a single allocation at cr=3D0 - * given cr=3D0 is an CPU-related optimization we shouldn't try to - * load too many groups, at some point we should start to use what - * we've got in memory. + /* + * now many real IOs to prefetch within a single allocation at + * cr=3DCR_POWER2_ALIGNED. Given cr=3DCR_POWER2_ALIGNED is an CPU-related + * optimization we shouldn't try to load too many groups, at some point + * we should start to use what we've got in memory. * with an average random access time 5ms, it'd take a second to get * 200 groups (* N with flex_bg), so let's make this limit 4 */ diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h index 56938532b4ce..042437d8860f 100644 --- a/fs/ext4/mballoc.h +++ b/fs/ext4/mballoc.h @@ -187,8 +187,8 @@ struct ext4_allocation_context { struct ext4_free_extent ac_f_ex; =20 /* - * goal len can change in CR1.5, so save the original len. This is - * used while adjusting the PA window and for accounting. + * goal len can change in CR_BEST_AVAIL_LEN, so save the original len. + * This is used while adjusting the PA window and for accounting. */ ext4_grpblk_t ac_orig_goal_len; =20 --=20 2.30.0 From nobody Sun Feb 8 23:26:06 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 3D8AE12AAF5; Tue, 26 Mar 2024 13:42:22 +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=1711460545; cv=none; b=M9MFq28UbTFA3koJMRFLaOJlLp2wIPptA/tB8gMMfH5ew1EwAfqqDLwPcCyjUhe43AnQlRFiXnbZAmW2gmbWgetzEN3A0F8+crl/xk2bNoT1RG5o7AAB6pqbRl44UkusmtHImZrLQcDdUoRMmV2n6E8Cw6uhS64oHFyEsqEoAMY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711460545; c=relaxed/simple; bh=rTsyKJ+6cQulWFeCm9Ty6fR+GXC23ReLWDU/rqmdMYk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=THuwM3QZ7ey4/RipYcSejN4114j2lAE7jFYgn0lndHl0kvQlDgcj65hq3rx4VnmLVEYYrvXXe4vbjB3b6SWrlAl28TPzu2414QHT0kN6kGO5Wl4Z4UtfmCPi0aoa50Bql4agBnMF6fVA0hSY5PwGQQsD2FFlUEX0bVoAA+8KBcU= 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 [172.19.93.142]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4V3rZW3QSMz4f3nKG; Tue, 26 Mar 2024 21:42:11 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.112]) by mail.maildlp.com (Postfix) with ESMTP id 92DBF1A016E; Tue, 26 Mar 2024 21:42:19 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP1 (Coremail) with SMTP id cCh0CgCHowy00AJmmQiSIA--.63567S7; Tue, 26 Mar 2024 21:42:19 +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 5/5] ext4: expand next_linear_group to remove repeat check for linear scan. Date: Wed, 27 Mar 2024 05:38:23 +0800 Message-Id: <20240326213823.528302-6-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--.63567S7 X-Coremail-Antispam: 1UD129KBjvJXoW7KFW3Xr1xGFyDJFykWrW5Awb_yoW8ZF43pa nxGFy7ur1xWFn8GFZ8Ga9Yg3WfKw18GF1UAryfG3s3tF13Arn8GFW2yr10vFy7GFZrCrnx Xr45AF1UC3Z7CaDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBIb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M280x2IEY4vEnII2IxkI6r1a6r45M2 8IrcIa0xkI8VA2jI8067AKxVWUAVCq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAv FVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJw A2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE 3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr2 1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r106r15McIj6I8E87Iv 67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41l42xK82IYc2 Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s02 6x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMIIYrxkI7VAKI48JMIIF0x vE2Ix0cI8IcVAFwI0_JFI_Gr1lIxAIcVC0I7IYx2IY6xkF7I0E14v26F4j6r4UJwCI42IY 6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280aV CY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IU058n7UUUUU== X-CM-SenderInfo: 5vklyvpphqwq5kxd4v5lfo033gof0z/ Content-Type: text/plain; charset="utf-8" Expand next_linear_group to remove repat check for linear scan. Signed-off-by: Kemeng Shi --- fs/ext4/mballoc.c | 37 ++++++------------------------------- 1 file changed, 6 insertions(+), 31 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 0f8a34513bf6..561780a274cd 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -1075,31 +1075,6 @@ static inline int should_optimize_scan(struct ext4_a= llocation_context *ac) return 1; } =20 -/* - * Return next linear group for allocation. If linear traversal should not= be - * performed, this function just returns the same group - */ -static ext4_group_t -next_linear_group(struct ext4_allocation_context *ac, ext4_group_t group, - ext4_group_t ngroups) -{ - if (!should_optimize_scan(ac)) - goto inc_and_return; - - if (ac->ac_groups_linear_remaining) { - ac->ac_groups_linear_remaining--; - goto inc_and_return; - } - - return group; -inc_and_return: - /* - * Artificially restricted ngroups for non-extent - * files makes group > ngroups possible on first loop. - */ - return group + 1 >=3D ngroups ? 0 : group + 1; -} - /* * ext4_mb_choose_next_group: choose next group for allocation. * @@ -1118,12 +1093,12 @@ static void ext4_mb_choose_next_group(struct ext4_a= llocation_context *ac, { *new_cr =3D ac->ac_criteria; =20 - if (!should_optimize_scan(ac) || ac->ac_groups_linear_remaining) { - *group =3D next_linear_group(ac, *group, ngroups); - return; - } - - if (*new_cr =3D=3D CR_POWER2_ALIGNED) { + if (!should_optimize_scan(ac)) + *group =3D *group + 1 >=3D ngroups ? 0 : *group + 1; + else if (ac->ac_groups_linear_remaining) { + ac->ac_groups_linear_remaining--; + *group =3D *group + 1 >=3D ngroups ? 0 : *group + 1; + } else if (*new_cr =3D=3D CR_POWER2_ALIGNED) { ext4_mb_choose_next_group_p2_aligned(ac, new_cr, group); } else if (*new_cr =3D=3D CR_GOAL_LEN_FAST) { ext4_mb_choose_next_group_goal_fast(ac, new_cr, group); --=20 2.30.0