From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 E5777374A09; Tue, 30 Jun 2026 15:34:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782833674; cv=none; b=QTJ8Ow8HQyCfmtgfXbNtxTUm/r7wlOPsjBBiyuDx/5CtckYta7RYJsyHCwQyiqQPlMeCzGCzOgtTCJKThhz3RD2N0LlGsAWqIG/e0+CaeH2nAuHKj/dps8MpEQnk5C+qE5fY+JlZuJVURhFME24FV6wkMONB2i7gIf84cZX73ok= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782833674; c=relaxed/simple; bh=eO7dqyKDNxjyixIIsd7yAS06Xv9odPctZBYJlcTUCFg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=knOvCRwfEsvotoitojiCs4WWpF1vFGyE2OH6mv+r85U0XO7UkziO4PGYxt7IQ6LsQWD2yv8rV9dSQkbYrEs4Av/vuOv/EZxoGwhrCpCZvwVRp2Ef9FECYB5hOCXyDmpk/I+rg32xKCo1XOEC6dvVyM9sfRe/uAqlDzFbacB3E08= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TZNEjJGA; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TZNEjJGA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 02ED11F000E9; Tue, 30 Jun 2026 15:34:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782833673; bh=OwS9P56nhbGkdFBYuAOEJp8Fgyu1if7n6nRSIyXvyMQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=TZNEjJGAsPcpJLEFlebROpZU+apG4a30zL8j62i9jmYlYeJaAl3aWQlvpiB3/57iO ETxjxR7Asn7ctiYJmN7/Od2ZN8KbQuJV65iFF706CP4OPQwPKwsepz718dXhwRucp0 2NBc8GhrByQt6Pp3eWpYyTBSMXTehwOXuHfeWNrgmTbu9Rz6AIdFpqW2SJ8y3Zdeq2 Tfms2tNuA836plyw/CpaFm58mHdf37Ng875h5vszKnGzd6risB6Js6BElWOrHHd2nf mniys/F0WnJZdP04Pt0WHwDSkiFnC++6NSa4dgJ12c0+2aGaO8VxNqXoFYDh2RiaRM D+RSM8fsIYWSg== Message-ID: <11a6d404-dc87-442a-9f2c-9cf34cae4869@kernel.org> Date: Tue, 30 Jun 2026 17:34:25 +0200 Precedence: bulk X-Mailing-List: linux-rt-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 05/16] mm/page_alloc: unify __alloc_frozen_pages[_nolock]_noprof() Content-Language: en-US To: Harry Yoo , Brendan Jackman , Andrew Morton , Suren Baghdasaryan , Michal Hocko , Johannes Weiner , Zi Yan , Muchun Song , Oscar Salvador , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Ying Huang , Alistair Popple , Hao Li , Christoph Lameter , David Rientjes , Roman Gushchin , Sebastian Andrzej Siewior , Clark Williams , Steven Rostedt Cc: Gregory Price , Alexei Starovoitov , Matthew Wilcox , Hao Ge , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev References: <20260629-alloc-trylock-v3-0-57bef0eadbc2@google.com> <20260629-alloc-trylock-v3-5-57bef0eadbc2@google.com> <397859cb-b127-4cc6-9c71-044afc99bf0c@kernel.org> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSNWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBrZXJuZWwub3JnPsLBsAQTAQoAWhYhBKlA1DSZLC6OmRA9UCJPp+fM gqZkBQJqFFy6GxSAAAAAAAQADm1hbnUyLDIuNSsxLjEyLDIsMgIbAwUJGtCBUAULCQgHAwUV CgkICwUWAgMBAAIeBQIXgAAKCRAiT6fnzIKmZJIUEADFx/tREzUImHrEwVHeSvDFmA7tJysI UVrlvrM09E7GIuzphzv7jYmo8n3ANpCczLEVr4G0syYQdTigaZgv3+FQDIIzhKih1IHhu1Ei XHlywNWKnQxxQEUNi5Mwx43wQz5XVw9F1A7gtKBKNtfogO511hAbrzagrYajyQacEJ/+sfhZ 9Da8ltHIXD8pcYaHUfQgEusCgmEd9+KrUwrTbckFKmYq5chuE6yJ4J0EmWknL096jIE6CnzF FRslQ3B1UKDjxVsm1ZHfir5NeWszLkTvGFsddFaWTgh8UycESG6VQzKXjjewXu2pG7YQYRpj QKm1W5X2TkwWkXRBZTmfmbhxIUMh3+zf5wQ463rSmDN/8v81tdqBtAW6rH/kzg1GvkaTHXn0 507yEHFzBksk2viAuIxxr7km8+/KARYLIdGtx30EG8cKzAUZOK6WqxtNCsXUJNrVE8CWrCaD icoNu7Fs1c5hmPHdSTnU48ce67449DdnO4neLSNhRiGlMHJgfJUmgrxu/hcYeOZ3haWmEQ2w uW1Mh01OHi8QZHCEyAbABrPs9GUgccc/4eYXX9hIgxfSkYzn8f+8NuIFPWl/0uTvjgqU29FQ SbzOLxHq9439Ox40G5mS5eZXRGxITYR+6TXvRGI6P/264jvflnr/pDGUttaikU+0W+1uxgKH cmYbEc7ATQRbGTU1AQgAn0H6UrFiWcovkh6EXVcl+SeqyO6JHOPm+e9Wu0Vw+VIUvXZVUVVQ La1PQDUi6j00ChlcR66g9/V0sPIcSutacPKfdKYOBvzd4rlhL8rfrdEsQw5ApZxrA8kYZVMh FmBRKAa6wos25moTlMKpCWzTH84+WO5+ziCTsTUZASAToz3RdunTD+vQcHj0GqNTPAHK63sf bAB2I0BslZkXkY1RLb/YhuA6E7JyEd2pilZOrIuBGl/5q2qSakgnAVFWFBR/DO27JuAksYnq +aH8vI0xGvwn75KqSk4UzAkDzWSmO4ZHuahKtQgZNsMYV+PGayRBX9b9zbldzopoLBdqHc4n jQARAQABwsF8BBgBCgAmAhsMFiEEqUDUNJksLo6ZED1QIk+n58yCpmQFAmfIHFQFCRYU6J8A CgkQIk+n58yCpmS2PA//bqN1LfcotmArgElsa+0EGZSQlYgK48pm8WAeTXTngudP9IJ4SuKY HR5RNjHcBeqN+Me0zxRqYzRb8nGanHEkDyf4Im8DQM8d6vbyU+FcPmG4skud4kgS1zMHnlVd SXfSIwKC/hKgdHG8aBV7545Lz9X6Iohea+94wneD0aw/hqF+QWewGZhWJriWAZtvEkzNjQOi 4U9F/trLten/x7bpphDSnDMKJtITbtzATT1Dq7o7VpIUK1nCTQALMuMjKCdi8OdU/+V+R3O4 0PXWvX8qrvqYapVbZ+9KqT74FsuB0Ya9uXwgBF2Q6cRuETZk5vqaqKxzqoQZCO8AOz/58j6O 2RHNy/mZEN+7tJ5Tsq42zVJ4jxsT8b9YplavCMsnBgDeRWhcbYhCyttoL7nYISyWg4kQYZ/P wIV3OuNv2f8iKYsxNsRuClOAF82+gvqOy1/1pprFjy8uo2pkoOrb63aOP3vO5VHnRKgra6dq NcaZ+c6J4H+nEJGi2SkHAUJz5oBzuThvPudLvPA/SK8sKoM01IRxSihev/S/5WLazXB1PGem OCbvzC1IjWJJraxiDJ5IygokapUa2RP7+WBR22skQ3SSl6G107QgWKSyTOGWEaRmV53vxQLV jXuCmzSSasTL60zq5yGrT4/DYQVSNEUiUbG4pYekxJujNeEDkUlky0Y= In-Reply-To: <397859cb-b127-4cc6-9c71-044afc99bf0c@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/30/26 15:36, Harry Yoo wrote: > > > On 6/29/26 10:11 PM, Brendan Jackman wrote: >> Currently the core allocator code is controlled by ALLOC_NOLOCK, but the >> main entry point function is significantly different from the normal >> __alloc_frozen_pages_nolock(), this is tiring when reading the code. >> >> Plumb the ALLOC_NOLOCK control one layer up in the call stack: create >> an alloc_flags argument to __alloc_frozen_pages_nolock() (which is only >> exposed to mm/) and then turn the nolock variant into a thin wrapper >> that just sets that flag (as well as handling NUMA_NO_NODE, similar to >> how some of the wrappers in gfp.h do). >> >> Rationale that this doesn't change anything: >> >> 1. Simple bits: A bunch of the nolock-specific handling is just moved to >> the new alloc_order_allowed(), alloc_trylock_allowed() and >> gfp_trylock. > > Right. > >> 2. __alloc_frozen_pages_noprof() has some extra logic that wasn't >> previously in the nolock variant: >> >> a. Application of gfp_allowed_mask; this only affects early boot, and >> only flags that affect the slowpath get changed here. > > gfp_allowed_mask clears __GFP_RECLAIM, and that means now allocations > with GFP_KERNEL during early boot would see > gfpflags_allow_spinning() = false. Is it a problem though? non-nolock allocations were affected before (the masking existed for those already) and will be affected now the same, and _nolock() allocations don't pass __GFP_RECLAIM in the first place, so the masking can't affect them? > The helper is not used in in the page allocator, but used in > memcg/stackdepot/page_owner. > >> b. Application of current_gfp_context() - also only affects the >> slowpath > > PF_MEMALLOC_PIN affects the fast path, but ALLOC_NOLOCK users > won't be affected. And it wouldn't be wrong if they were? It only clears __GFP_MOVABLE? > What about alloc_flags_nofragment/nonblocking()? ALLOC_NOFRAGMENT due to e.g. defrag_mode could be a problem indeed, if there's no slowpath. Make ALLOC_NOLOCK override it? nonblocking() is probably fine? >