From mboxrd@z Thu Jan 1 00:00:00 1970 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E4CDD10A88F6 for ; Thu, 26 Mar 2026 17:54:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EC6E26B0088; Thu, 26 Mar 2026 13:54:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E77A56B0089; Thu, 26 Mar 2026 13:54:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D66AB6B008A; Thu, 26 Mar 2026 13:54:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id C5F3B6B0088 for ; Thu, 26 Mar 2026 13:54:12 -0400 (EDT) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 8C1DEC207A for ; Thu, 26 Mar 2026 17:54:12 +0000 (UTC) X-FDA: 84588963144.05.7B15B1C Received: from mail-wm1-f50.google.com (mail-wm1-f50.google.com [209.85.128.50]) by imf14.hostedemail.com (Postfix) with ESMTP id 7475C100011 for ; Thu, 26 Mar 2026 17:54:10 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=gmail.com header.s=20251104 header.b=tAuSQioc; dmarc=pass (policy=none) header.from=gmail.com; arc=pass ("google.com:s=arc-20240605:i=1"); spf=pass (imf14.hostedemail.com: domain of joannelkoong@gmail.com designates 209.85.128.50 as permitted sender) smtp.mailfrom=joannelkoong@gmail.com ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1774547650; a=rsa-sha256; cv=pass; b=b3X+RFAWCCadIbfJGGCNgkO2QjZatRiapAp9X4HD7mAzIDJkbWM/lEwCCVYtOEW94S0MMn Q5Ei9JK9zx4YyS3dYlKabboT4mdpQPEroEfvyTEzSdFJtSJ9FjC32JVmV+X0Ny828ol7xi M3SQvWU0Ms1+A2yKVoCj2VD1oMScgUE= ARC-Authentication-Results: i=2; imf14.hostedemail.com; dkim=pass header.d=gmail.com header.s=20251104 header.b=tAuSQioc; dmarc=pass (policy=none) header.from=gmail.com; arc=pass ("google.com:s=arc-20240605:i=1"); spf=pass (imf14.hostedemail.com: domain of joannelkoong@gmail.com designates 209.85.128.50 as permitted sender) smtp.mailfrom=joannelkoong@gmail.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1774547650; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=2b1UX5269EiDhfq1pawQFex+1Y1S6Ex1txW/zzYwTBo=; b=nAsAmRLr+He327rAJ7UfkMMFiiKnZGa2w+EYZSpgMpuVMWQKIh8sxdEeKd/sI8mn5p5tzp qlRPBoNNzShalL/sOIpQ7rSJtN1hrBKog08m0PaS579cNdT3C3oKlJ1Vfwf/Ej+nHrUc1S EtMgzJB7/ZYKEzMYmnV05xQXltmWmIQ= Received: by mail-wm1-f50.google.com with SMTP id 5b1f17b1804b1-486ff3a0fc1so12689855e9.2 for ; Thu, 26 Mar 2026 10:54:10 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1774547649; cv=none; d=google.com; s=arc-20240605; b=LSRDYYxRZpAMd/7KYgFcNAA+HwVrfWXvGtxElcyOXr24wfflTnfzauHyZB4y+K9H3W pLzavDJei577gm0Z5LqZdnB7pqzUWtOA1Carp/HVieq0UdXR7t29GZqn1pNnfxVEc0fK 0RzjcKTIt2R+XGHa/kYvdTzEVK/n0WUzTXbpTDjqipNxT2ULOiMk9UkRWKPK917JwaB+ QTpm+zf1EkHdPKe+l5kjrn/GdzBZJnsFqwHHVrzjqwh+2wJyj5SgCKt0dCOqwcYOwJYH mEbLWIfeNPmX50voI/3eTo5LY64vTsZnFOBPtUb8PgJzghKPKDWjArbzpPqNWPDbKLnU mOMA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20240605; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:dkim-signature; bh=2b1UX5269EiDhfq1pawQFex+1Y1S6Ex1txW/zzYwTBo=; fh=DVNBMlRgYO1UeTMkIAJu+4bU9fN/8DGNfZbSl6ocPEw=; b=jV7fJ5n6w0aY5RtO17Db1hOIHv/kyfsa82+MKNh8LG7wYmbJm0qDAuy0Ec21OJvLNm XaaUdtjhvWWmQ4YKmuFr+jWZIHbxbzdiS5x4r9wCdkciHx1LcN8YUsER6+r0S4I8IWN7 j4Rf/rcY3O3+DfnxzbPKTwZpu0Wk7Wjy2a8S7KlFx3NH49n+PBKH9N9ArPEM1tAQtJiy f2niiYkbVusj+NFiSqSUAQSqB0f7f9CjsZNbpXN2x4WK+z3hhfB2vTiamiL+yxstzXLL wFiOHeMv8Wai2cyoYZkrlWBxG07eY7nGvvgVm8K+b3ay+uJ8w+0ygbNDUJ5tN5lRHa/G QWCQ==; darn=kvack.org ARC-Authentication-Results: i=1; mx.google.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1774547649; x=1775152449; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=2b1UX5269EiDhfq1pawQFex+1Y1S6Ex1txW/zzYwTBo=; b=tAuSQiocKfkApNy4RLuDfPg3YT79Op2RyVsknv7rsBok4N7CGMfWuIW7rswmVvh3Wn IsiORgbEU4WC9rw26EFno5vYzUM+XY1bhl2PCVKYeXE1i3fOLTQxVtvNSVcNjfD8smVy HBvn/06pyUUQcXiTUX96+p8ipTxDUNpOool91xEhDmYtEUZpd0H7L1bzkYph2ko+NJes TH55BdB0GvyRb8RKuqEUgnYgFEQbTcQrWmtH+zzFkTiISARhMifQ2syFtEtYrdpJzFlJ hLw7q9XO8GRRJTElrEKEo3MRnke9ajxtoeeWpNVcA85O3lVaGeETlXMn0iRtrfXy6SQG vfDA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774547649; x=1775152449; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=2b1UX5269EiDhfq1pawQFex+1Y1S6Ex1txW/zzYwTBo=; b=iiLC4R30xAyhhvfrlG8X8xKisrBywXnK857th8JoV77woeiFJvgfDmB/8/nhkE+tjP wgxoKeYUK4Q22qF77rgtv+KdiYG+jHbY/ceHL+WTromYxWq8KB8ckzf1Lv2b086B3ojK S+vyeo/3CchT4Za3+Yf9jbeI/h+/JJ3h//OWKIkJ6wlbdskpD5Yz+Qd7Fwy/ecigsnKq 25wFu935zj9Pk6SBZlyNHV3OlyPpiNMMuxOy5kosObEpvh/bcfkmTEOkKZ18Y6N7scI9 jcTUcXIDCWXY5QpBuPle6y8eBhPCGCakTG9gWQo4ng+lSdFesMT4ycwEtVJq8qYSsSjV j2UA== X-Forwarded-Encrypted: i=1; AJvYcCUFkk+Brv7IB5EVTPui8Ub3hcLnBiPnuqxBr6uhXo7aE/JWN1lVvRqGOmmTIOVpZeuSCXeJmnyLfw==@kvack.org X-Gm-Message-State: AOJu0Yzszl26+3+8Qm4Sv+IGt2SN9JpHdcW5t6gnw82aXz9R2iWG3xY8 5JPNH0dI0BOTwvnmAq7WBN1xCfXb2jQFodQCw+pqYAmJGrSzsLhNGfqMJH5hxnnLujs1VzP4VDj i3HWmdtVEJzep8Hd2MMTXPfbypqVlPobnrsdvRWc= X-Gm-Gg: ATEYQzwpbcT/+4zuDJ+mx+ld8QxBqXXjlfEuRMxA+OrH35pfxyPNKbcGaqxOYTXJR42 3NmgvmrXtfWvN6dy/G2WJhlu0WNI1zkBgLxOxR/65fMn7XZis9W13RHgfQORjkgA6g5Vc4LOox0 77AoJuVMhju6+Mp18WJi8iNxb1HLpTqkvzv/JEI+eQgUjBpN9u4J4Nnf5dcoftc+Wy76qL7skC9 HfmQsdSbd+KPCXMPIFQDwDHUdDu6iw74VrV8NC7Kn2n0NzICUdmy3dkL+5/WbWtXfyKem6iVhOq aWC7AyA5haovG9r6 X-Received: by 2002:a05:600c:528e:b0:485:3fc8:de9c with SMTP id 5b1f17b1804b1-48715fd4dd8mr131671765e9.12.1774547648461; Thu, 26 Mar 2026 10:54:08 -0700 (PDT) MIME-Version: 1.0 References: <20260326001337.828947-1-joannelkoong@gmail.com> In-Reply-To: From: Joanne Koong Date: Thu, 26 Mar 2026 10:53:57 -0700 X-Gm-Features: AQROBzBk1MK2sKpbF7oHxmG14dUDSRU0L6vuO6VBQC9M1qo-02BtGUnmY2CGWLQ Message-ID: Subject: Re: [PATCH v1] mm: fix writeback regression for strictlimit BDIs To: Christoph Hellwig Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, jack@suse.cz, willy@infradead.org, miklos@szeredi.hu, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: azhwwyycm7u588d1jg1ku3cqynxqxfja X-Rspamd-Queue-Id: 7475C100011 X-Rspam-User: X-Rspamd-Server: rspam03 X-HE-Tag: 1774547650-982928 X-HE-Meta: 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 jBZaruJR G15tVWPyUZojj+WsMhEfQPZVdJhiBMJoIIkEXIq1COH+eeO8zMMX8bHn5JZyANHjYbQl+HsXL+WmM7er1ecxK3kBWiF/P1ahEBdErz1GMgnCXD261KTbSJxx6+A44iWrViwd4yl2e1JSwvAcJnrPIcrqx47KRg2tlHsPe/+D4x0pMWmu3CvomWOJRu7NFTqfS3mqx9UHslNN0EehqzEV2roXTWzhB9G/m8MmJpLHLUBY6F8Cd7d26eKLTw5nhf1QxCs3u0OYBt4iFZteDMTPw093OAQZ/ov2pfzOZSRfqulqyyjbp8XhUIRV/PAIntgYkx3HOcYvKl+l8IpwB9HVaUZgo18zrdnbXhVtzoIsNCYej/x+w+Tkeu6jYwHJLfi2+3uzIcj05SvXYnMIFgpQeYXHSX4FpGAu9bNwEM8See7rKVMW2Vd6EwjnmOubSxgDxrne3A0RhgL/uwXg= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Mar 25, 2026 at 10:50=E2=80=AFPM Christoph Hellwig wrote: > > On Wed, Mar 25, 2026 at 05:13:37PM -0700, Joanne Koong wrote: > > Commit 64dd89ae01f2 ("mm/block/fs: remove laptop_mode") removed this > > unconditional writeback kick from balance_dirty_pages(): > > > > if (unlikely(!writeback_in_progress(wb))) > > wb_start_background_writeback(wb); > > Yes, that looks like a bug. > > > This fixes the issue by kicking off the flusher if wb_dirty exceeds > > wb_bg_thresh for strictlimit BDIs. This restores performance back to it= s > > original baseline. > > What speaks against just reinstating the old-code as-is minus the > misleading latop_mode comment? > I thought those two lines were unnecessary for nonstrictlimited bdis but after reading Jan's feedback, you're right this should just reinstate the old code as is. Thanks, Joanne