From nobody Wed Sep 10 06:13:11 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5AC52C64EC4 for ; Fri, 3 Mar 2023 09:20:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230425AbjCCJUo (ORCPT ); Fri, 3 Mar 2023 04:20:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49900 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230078AbjCCJT4 (ORCPT ); Fri, 3 Mar 2023 04:19:56 -0500 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E0A441B7F; Fri, 3 Mar 2023 01:19:55 -0800 (PST) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4PSj9L6Jdfz4f3nV9; Fri, 3 Mar 2023 17:19:50 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP4 (Coremail) with SMTP id gCh0CgDnnbGyuwFkFpqfEg--.45687S15; Fri, 03 Mar 2023 17:19:52 +0800 (CST) From: Kemeng Shi To: tytso@mit.edu, adilger.kernel@dilger.ca, ojaswin@linux.ibm.com, ritesh.list@gmail.com Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, shikemeng@huaweicloud.com Subject: [PATCH v3 13/20] ext4: remove ac->ac_found > sbi->s_mb_min_to_scan dead check in ext4_mb_check_limits Date: Sat, 4 Mar 2023 01:21:13 +0800 Message-Id: <20230303172120.3800725-14-shikemeng@huaweicloud.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20230303172120.3800725-1-shikemeng@huaweicloud.com> References: <20230303172120.3800725-1-shikemeng@huaweicloud.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: gCh0CgDnnbGyuwFkFpqfEg--.45687S15 X-Coremail-Antispam: 1UD129KBjvJXoW7KrW5tF1rZrW3CryUCr17Wrg_yoW8Ar1Upa nrCryUG3yxWr1a9wsrK3Z8W3WFkw4fKFyxtryxur1rA3W7X3yqka9xtFyUZF9Fyws3Z3Wf ZFyYvr4UGw4Ika7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPF14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2jI8I6cxK62vIxIIY0VWUZVW8XwA2048vs2IY02 0E87I2jVAFwI0_JF0E3s1l82xGYIkIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0 rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6x IIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xv wVC2z280aVCY1x0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFc xC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_ Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2 IErcIFxwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E 14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIx kGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVW8JVW5JwCI42IY6xIIjxv20xvEc7CjxVAF wI0_Cr0_Gr1UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVW8JV WxJwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjTRKfOw UUUUU X-CM-SenderInfo: 5vklyvpphqwq5kxd4v5lfo033gof0z/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Only call trace of ext4_mb_check_limits is as following: ext4_mb_complex_scan_group ext4_mb_measure_extent ext4_mb_check_limits(ac, e4b, 0); ext4_mb_check_limits(ac, e4b, 1); If the first ac->ac_found > sbi->s_mb_max_to_scan check in ext4_mb_check_limits is met, we will set ac_status to AC_STATUS_BREAK and call ext4_mb_try_best_found to try to use ac->ac_b_ex. If ext4_mb_try_best_found successes, then block allocation finishs, the removed ac->ac_found > sbi->s_mb_min_to_scan check is not reachable. If ext4_mb_try_best_found fails, then we set EXT4_MB_HINT_FIRST and reset ac->ac_b_ex to retry block allocation. We will use any found free extent in ext4_mb_measure_extent before reach the removed ac->ac_found > sbi->s_mb_min_to_scan check. In summary, the removed ac->ac_found > sbi->s_mb_min_to_scan check is not reachable and we can remove that dead check. Signed-off-by: Kemeng Shi Reviewed-by: Ojaswin Mujoo --- fs/ext4/mballoc.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 16f926675006..5315c67905f6 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2039,8 +2039,7 @@ static void ext4_mb_check_limits(struct ext4_allocati= on_context *ac, if (bex->fe_len < gex->fe_len) return; =20 - if ((finish_group || ac->ac_found > sbi->s_mb_min_to_scan) - && bex->fe_group =3D=3D e4b->bd_group) { + if (finish_group && bex->fe_group =3D=3D e4b->bd_group) { /* recheck chunk's availability - we don't know * when it was found (within this lock-unlock * period or not) */ --=20 2.30.0