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 A65CFF588C7 for ; Mon, 20 Apr 2026 13:16:20 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CC2156B009D; Mon, 20 Apr 2026 09:16:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C4BF66B009E; Mon, 20 Apr 2026 09:16:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B13316B00A3; Mon, 20 Apr 2026 09:16:19 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 9C5E46B009D for ; Mon, 20 Apr 2026 09:16:19 -0400 (EDT) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 0E6461B8EE0 for ; Mon, 20 Apr 2026 13:16:19 +0000 (UTC) X-FDA: 84678982878.01.ED16807 Received: from out-176.mta1.migadu.com (out-176.mta1.migadu.com [95.215.58.176]) by imf17.hostedemail.com (Postfix) with ESMTP id CCEE940014 for ; Mon, 20 Apr 2026 13:16:16 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=T2LV6+Is; spf=pass (imf17.hostedemail.com: domain of usama.arif@linux.dev designates 95.215.58.176 as permitted sender) smtp.mailfrom=usama.arif@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1776690977; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=BsatqlpFXZFNi8Kl9ZLgdLvl4wOAHcOCp2o0dzIKpJY=; b=LZBloOcttXhfTWFcEA47gKSIxPyFgKgTxUUInEjzoILgBxmjI7j6ITDhgbOQYSn3Xza7qj vqrv6zuCcBy9Wa3D9k87ZHM6R/foVMK+QSBWpsfZqTnYObf0LJhRF6yj+moktVfVikpaJ3 ju6Iolp1jS46+xQuSJHwRtkCw8Ib76g= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=T2LV6+Is; spf=pass (imf17.hostedemail.com: domain of usama.arif@linux.dev designates 95.215.58.176 as permitted sender) smtp.mailfrom=usama.arif@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1776690977; a=rsa-sha256; cv=none; b=aRg345USHt5DUmZBU8Gjdd4h0SJKIri8NDq1Q3utVj2b6TG07T9cP31HzRXmxPQhVM3Zea G0au9A4y2SfAgGC3qQZqooyd9QqJU8P13GnxyJ/lR7hb3wT7Hkn0+pyWW9PSBFi+OJwFzi qM2bmXqZ3wiYIsTjvWbiZuZzdlSqEpQ= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1776690974; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BsatqlpFXZFNi8Kl9ZLgdLvl4wOAHcOCp2o0dzIKpJY=; b=T2LV6+IsNzeXUOci7LW3i7gkiXJBoEaQxrMm8jqfQoQgsCiebwzcF3GmF6j5s+nonfNmAl ihVck8om9+Gy2IOQu2HefU5g4FAUS4zaBANZdgWWntieO5VCLJfyqhW7Y5foXCOqj5+976 y6CLSWU58gqI2rcnbNAfmn6UjTr3xLA= From: Usama Arif To: Nico Pache Cc: Usama Arif , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, akpm@linux-foundation.org, anshuman.khandual@arm.com, apopple@nvidia.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, byungchul@sk.com, catalin.marinas@arm.com, cl@gentwo.org, corbet@lwn.net, dave.hansen@linux.intel.com, david@kernel.org, dev.jain@arm.com, gourry@gourry.net, hannes@cmpxchg.org, hughd@google.com, jack@suse.cz, jackmanb@google.com, jannh@google.com, jglisse@google.com, joshua.hahnjy@gmail.com, kas@kernel.org, lance.yang@linux.dev, Liam.Howlett@oracle.com, ljs@kernel.org, mathieu.desnoyers@efficios.com, matthew.brost@intel.com, mhiramat@kernel.org, mhocko@suse.com, peterx@redhat.com, pfalcato@suse.de, rakie.kim@sk.com, raquini@redhat.com, rdunlap@infradead.org, richard.weiyang@gmail.com, rientjes@google.com, rostedt@goodmis.org, rppt@kernel.org, ryan.roberts@arm.com, shivankg@amd.com, sunnanyong@huawei.com, surenb@google.com, thomas.hellstrom@linux.intel.com, tiwai@suse.de, usamaarif642@gmail.com, vbabka@suse.cz, vishal.moola@gmail.com, wangkefeng.wang@huawei.com, will@kernel.org, willy@infradead.org, yang@os.amperecomputing.com, ying.huang@linux.alibaba.com, ziy@nvidia.com, zokeefe@google.com Subject: Re: [PATCH 7.2 v16 03/13] mm/khugepaged: rework max_ptes_* handling with helper functions Date: Mon, 20 Apr 2026 06:15:48 -0700 Message-ID: <20260420131549.3673619-1-usama.arif@linux.dev> In-Reply-To: <20260419185750.260784-4-npache@redhat.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: CCEE940014 X-Stat-Signature: wsicmbbq7zs9n3na53w3kyk5t3qzahqc X-Rspam-User: X-HE-Tag: 1776690976-616750 X-HE-Meta: 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 W/GWYBtT TTGwe18kXb7pF9fZtwpTO+E40l9FVB4Rvmxtr1Vlkb5z+DYZ7jIH7+D3wGvfxLaZY1fzz7n8XK2Zk3lHNjaFWAk4xOVgKWADFIjceFrSB8SBeKZh9YP/9UXepwmD2ZoQ5L+wbQ9pRDMfgehi98PVcsPh1wp9L+hEQeUUP4biLxxmATwMja3KT4xSpYxREJ6fmNdpLH0ZZBmEl2KK5+7O4mNfdQA4sYACnaS6jUK5UaYuguI+PRTokloQi3WN9BwJ976vFlRG3JlQEOvvnH89Rqiazg2FJB6HItHNJBXTdyKXE18akY3U5V1F4GS0yQrufIxv6C03oC/VZCX5ZPzbzn2WOy9lU4DN82njIxL3d2fTijdQ= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sun, 19 Apr 2026 12:57:40 -0600 Nico Pache wrote: > The following cleanup reworks all the max_ptes_* handling into helper > functions. This increases the code readability and will later be used to > implement the mTHP handling of these variables. > > With these changes we abstract all the madvise_collapse() special casing > (dont respect the sysctls) away from the functions that utilize them. And > will later in this series to cleanly restrict mTHP collapses behaviors. > > Suggested-by: David Hildenbrand > Signed-off-by: Nico Pache > --- > mm/khugepaged.c | 114 +++++++++++++++++++++++++++++++++--------------- > 1 file changed, 78 insertions(+), 36 deletions(-) > The old code re-read khugepaged_max_ptes_* on every loop iteration; the new code snapshots them once per scan call. If userspace writes the sysctl mid-scan, old behavior reacted within the scan, new behavior uses the value sampled at entry. This is completely ok IMO, but might be good to call out. Also might be good to write no functional change intended apart from above in the commit message? Acked-by: Usama Arif