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 81F24CD4F54 for ; Wed, 27 May 2026 15:41:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9801E6B00AA; Wed, 27 May 2026 11:41:26 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 958126B00AB; Wed, 27 May 2026 11:41:26 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 86BA96B00AC; Wed, 27 May 2026 11:41:26 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 742836B00AA for ; Wed, 27 May 2026 11:41:26 -0400 (EDT) Received: from smtpin24.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 3A9111405DF for ; Wed, 27 May 2026 15:41:26 +0000 (UTC) X-FDA: 84813614172.24.8901B18 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) by imf16.hostedemail.com (Postfix) with ESMTP id 691E8180003 for ; Wed, 27 May 2026 15:41:23 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=surriel.com header.s=mail header.b="GEnwN/FA"; spf=pass (imf16.hostedemail.com: domain of riel@surriel.com designates 96.67.55.147 as permitted sender) smtp.mailfrom=riel@surriel.com; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1779896484; 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=oikUtBRFh/gGkdwzqzvGVc48zMkmVITOctUzSsP8HHk=; b=M6u3ebsrMigOVHPIqVT8sTuyI0+HI6a60A+BRLhciU1DxFaBiKkk5Hy+NRxxmfPsCPAUlF tiU7vyIlFsYUlSsq9Gmw3RXwiDsKrpX97dsPb4dnaXMqKhXHRCGyziLkdd5xAX688gmGJX tB8KI7pkKFpbJs9lZUd7BKgQkY2pNog= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=surriel.com header.s=mail header.b="GEnwN/FA"; spf=pass (imf16.hostedemail.com: domain of riel@surriel.com designates 96.67.55.147 as permitted sender) smtp.mailfrom=riel@surriel.com; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1779896484; a=rsa-sha256; cv=none; b=IR7wBc3O5ToOlJjTM4UKd5kn4SIlC/G6XvZhdkMyRZvoI6ClqZjOsQscFlZctrZ5IkPUG/ e862x04LhY2NRqoHIFMH6KebPrl+G9KmiVz8Rfnw0s5rQDzF1Fho2Oa8Xo3lMj++Uhg+8a Vr5uFv6deXufBJCG0k0fANuCzj66k0o= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=surriel.com ; s=mail; h=MIME-Version:Content-Transfer-Encoding:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=oikUtBRFh/gGkdwzqzvGVc48zMkmVITOctUzSsP8HHk=; b=GEnwN/FAU0Tlq02oj3pLcpuzji +kRli8umqeCjmk8Bx0fB4zeC7dar9/rXPYOT9iER+KSmtPh1wZX4+bSxqA4A7QUFNbm/vuTPEoV0H t+p++TWHiGBpMD56VidMG/OxCEbW2JRkmZV0vrLZ1lil12Wua/81eniQsLDfhwXOYQ8+dclFv/6WE QecROif82UlI2ySdP/ogG91qgIRHgR13/TIRODYP/0DGv7qEz8KP8KGuMpqs4N3ksosySwP+/6BiN 60dh16nTjptoRt0k628WKTOiDJ3a3jaeIshOjc2WgtkQ1XneGkQMgYZxnR+sHVrjusWYuLDOTz/tP I4UOS1Xw==; Received: from fangorn.home.surriel.com ([10.0.13.7]) by shelob.surriel.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.97.1) (envelope-from ) id 1wSGNV-000000005VD-2o8E; Wed, 27 May 2026 11:41:05 -0400 Message-ID: <2ecf71858845e7d14c718b1a6845389cb78b986e.camel@surriel.com> Subject: Re: [RFC PATCH 05/40] mm: page_alloc: remove watermark boost mechanism From: Rik van Riel To: Usama Arif Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, linux-mm@kvack.org, david@kernel.org, willy@infradead.org, surenb@google.com, hannes@cmpxchg.org, ljs@kernel.org, ziy@nvidia.com, fvdl@google.com Date: Wed, 27 May 2026 11:41:05 -0400 In-Reply-To: <20260526140204.1390573-1-usama.arif@linux.dev> References: <20260526140204.1390573-1-usama.arif@linux.dev> Autocrypt: addr=riel@surriel.com; prefer-encrypt=mutual; keydata=mQENBFIt3aUBCADCK0LicyCYyMa0E1lodCDUBf6G+6C5UXKG1jEYwQu49cc/gUBTTk33A eo2hjn4JinVaPF3zfZprnKMEGGv4dHvEOCPWiNhlz5RtqH3SKJllq2dpeMS9RqbMvDA36rlJIIo47 Z/nl6IA8MDhSqyqdnTY8z7LnQHqq16jAqwo7Ll9qALXz4yG1ZdSCmo80VPetBZZPw7WMjo+1hByv/ lvdFnLfiQ52tayuuC1r9x2qZ/SYWd2M4p/f5CLmvG9UcnkbYFsKWz8bwOBWKg1PQcaYHLx06sHGdY dIDaeVvkIfMFwAprSo5EFU+aes2VB2ZjugOTbkkW2aPSWTRsBhPHhV6dABEBAAG0HlJpayB2YW4gU mllbCA8cmllbEByZWRoYXQuY29tPokBHwQwAQIACQUCW5LcVgIdIAAKCRDOed6ShMTeg05SB/986o gEgdq4byrtaBQKFg5LWfd8e+h+QzLOg/T8mSS3dJzFXe5JBOfvYg7Bj47xXi9I5sM+I9Lu9+1XVb/ r2rGJrU1DwA09TnmyFtK76bgMF0sBEh1ECILYNQTEIemzNFwOWLZZlEhZFRJsZyX+mtEp/WQIygHV WjwuP69VJw+fPQvLOGn4j8W9QXuvhha7u1QJ7mYx4dLGHrZlHdwDsqpvWsW+3rsIqs1BBe5/Itz9o 6y9gLNtQzwmSDioV8KhF85VmYInslhv5tUtMEppfdTLyX4SUKh8ftNIVmH9mXyRCZclSoa6IMd635 Jq1Pj2/Lp64tOzSvN5Y9zaiCc5FucXtB9SaWsgdmFuIFJpZWwgPHJpZWxAc3VycmllbC5jb20+iQE +BBMBAgAoBQJSLd2lAhsjBQkSzAMABgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRDOed6ShMTe g4PpB/0ZivKYFt0LaB22ssWUrBoeNWCP1NY/lkq2QbPhR3agLB7ZXI97PF2z/5QD9Fuy/FD/jddPx KRTvFCtHcEzTOcFjBmf52uqgt3U40H9GM++0IM0yHusd9EzlaWsbp09vsAV2DwdqS69x9RPbvE/Ne fO5subhocH76okcF/aQiQ+oj2j6LJZGBJBVigOHg+4zyzdDgKM+jp0bvDI51KQ4XfxV593OhvkS3z 3FPx0CE7l62WhWrieHyBblqvkTYgJ6dq4bsYpqxxGJOkQ47WpEUx6onH+rImWmPJbSYGhwBzTo0Mm G1Nb1qGPG+mTrSmJjDRxrwf1zjmYqQreWVSFEt26tBpSaWsgdmFuIFJpZWwgPHJpZWxAZmIuY29tP okBPgQTAQIAKAUCW5LbiAIbIwUJEswDAAYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQznneko TE3oOUEQgAsrGxjTC1bGtZyuvyQPcXclap11Ogib6rQywGYu6/Mnkbd6hbyY3wpdyQii/cas2S44N cQj8HkGv91JLVE24/Wt0gITPCH3rLVJJDGQxprHTVDs1t1RAbsbp0XTksZPCNWDGYIBo2aHDwErhI omYQ0Xluo1WBtH/UmHgirHvclsou1Ks9jyTxiPyUKRfae7GNOFiX99+ZlB27P3t8CjtSO831Ij0Ip QrfooZ21YVlUKw0Wy6Ll8EyefyrEYSh8KTm8dQj4O7xxvdg865TLeLpho5PwDRF+/mR3qi8CdGbkE c4pYZQO8UDXUN4S+pe0aTeTqlYw8rRHWF9TnvtpcNzZw== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-2.fc42) MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 691E8180003 X-Stat-Signature: mjq35a8mzawekpfsfrepazf7p96sq7ew X-HE-Tag: 1779896483-145496 X-HE-Meta: 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 klU5er2Q B6zP75A5rMLVkhJ2BRq+RDBbwXikpY1G6KemYCeDBNGpjv0Eh0xeH3mpTQBMIoVzd+qS38arjGuqx04j/NexEr0zcGSbGfaVxs2n8I5UbpGhZfky53lzFAvc4lRPiPcDiajVBJaBrLDBpknONUGEbfG/EcnTgmRV78A9x8eq0iBSYMBhgR1xl06KVylHj5biqL5LsKhEV3b+3XTmstyTMJuepJoBF7vXPI5wmq+90Qt4yz+CWwY1szk97Mt+zrzp6W/HUv3zDmd6lCTG4GYBQWuKU3SsSWXD4gWe3CvrPLXbDvi1VCed1CBb2PQ+OLPwnQQd7+n1/xoREb+U= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 2026-05-26 at 07:02 -0700, Usama Arif wrote: > On Wed, 20 May 2026 10:59:11 -0400 Rik van Riel > wrote: >=20 > > @@ -7187,14 +7117,6 @@ static const struct ctl_table > > page_alloc_sysctl_table[] =3D { > > =C2=A0 .proc_handler =3D min_free_kbytes_sysctl_handler, > > =C2=A0 .extra1 =3D SYSCTL_ZERO, > > =C2=A0 }, > > - { > > - .procname =3D "watermark_boost_factor", > > - .data =3D &watermark_boost_factor, > > - .maxlen =3D > > sizeof(watermark_boost_factor), > > - .mode =3D 0644, > > - .proc_handler =3D proc_dointvec_minmax, > > - .extra1 =3D SYSCTL_ZERO, > > - }, >=20 >=20 > This is a userspace-visible removal. Writes to > /proc/sys/vm/watermark_boost_factor will now return -ENOENT instead > of being > accepted, breaking userspace. >=20 > I am not sure whats been done in the past, but we need to add a > Documentation/ABI/removed/ note explaining what replaces it (SPB > steering). > and also maybe keep the sysctl entry as a no-op with warning for a > few > cycles before deletion? I'll just drop this patch for now. While we no longer need it, and the watermark boosting can cause a little bit of harm at times, this probably isn't worth the extra code churn in this series. --=20 All Rights Reversed.