From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 61BA418EBE for ; Thu, 4 Jan 2024 05:38:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="E5hSBD1T" Received: by smtp.kernel.org (Postfix) with ESMTPS id E2B50C433CC for ; Thu, 4 Jan 2024 05:38:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1704346716; bh=NUqRJIbij3iPXqplD7hcP/Z66Ir0hE4wJeBiScpw1pA=; h=From:To:Subject:Date:In-Reply-To:References:From; b=E5hSBD1T/XEoAiSKyx8Mb/AaC7hph7t0VbCmJ5inBIkYcW3xfdoXO1SDz6H7m4yVN NEqq+onVzvf/3Hr4X9WsW5VZBBxUjoKbBRiUcT+rdI3fqn2U3vDam4TARexZ/Amd5c LluG0tCfoh0utth7ZuW38Ku9GF4jLvUMWXWZgNjGqsyOpEz5QzDPbjxd7fpFNd8Pmw UvglnqS/3u2E0QopZLn6i24KP6AnHVDlghBCRuOMb3Wz6LBTaYFGnx/xhNIkPCknL5 Vh/zcHT+W2cxnscAJsByKt2Pi+3hLscGn0gaIgkOX/RKTdw0+sYLSE/j080k2yKH1B Eq0WuMs2Y2iEQ== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id CEBD8C4332E; Thu, 4 Jan 2024 05:38:36 +0000 (UTC) From: bugzilla-daemon@kernel.org To: linux-ext4@vger.kernel.org Subject: [Bug 217965] ext4(?) regression since 6.5.0 on sata hdd Date: Thu, 04 Jan 2024 05:38:36 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: AssignedTo fs_ext4@kernel-bugs.osdl.org X-Bugzilla-Product: File System X-Bugzilla-Component: ext4 X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: ojaswin.mujoo@ibm.com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: fs_ext4@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 https://bugzilla.kernel.org/show_bug.cgi?id=3D217965 --- Comment #61 from Ojaswin Mujoo (ojaswin.mujoo@ibm.com) --- Hi Matthew, thanks for confirming. So as pointed out in comment 9 [1], for = the above steps to disable CR_BEST_AVAIL_LEN code did not fix the issue. My suspicion is that this issue can occur either in CR_GOAL_LEN_FAST or CR_BEST_AVAIL_LEN lookup, depending on the block groups being searched. Probably for you, it was occurring during CR_BEST_AVAIL_LEN lookup and hence disabling that code fixed it.=20 Further, as Carlos pointed out above, they are able to see this in all 6.* kernels which means this is happening before CR_BEST_AVAIL_LEN was introduc= ed however it seems to be much easier to trigger in 6.5+ kernels. Now, assuming the above theory is correct, then in cases where this is triggered from CR_GOAL_LEN_FAST, it should ideally happen easily in pre 6.5 kernels as wel= l, but it doesn't, which makes me think that there might be some other related changes in 6.5 that might be making it easier to trigger. I'll try to play around a bit more with this. Also, as for higher CPU usage, how high are we talking about? So CR_BEST_AVAIL_LEN does add some extra cyc= les at the cost of generally faster allocation in fragmented filesystems, howev= er since you have disabled it we shouldn't ideally be seeing it. Also, does the CPU util consistently drop when you commented out that code? [1] https://bugzilla.kernel.org/show_bug.cgi?id=3D217965#c9 --=20 You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.=