From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-173.mta1.migadu.com (out-173.mta1.migadu.com [95.215.58.173]) (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 2438B395AF5 for ; Wed, 17 Jun 2026 17:14:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781716494; cv=none; b=o5HjzcXtDfWwgvgJ93dvdIwNmKTYpV58r41chPFNPr13rdukjWDfgQrlAKabALNAjwFZlNwPs0ybMHZa0TPFb2A5NNB8aOsr8ebOxCTfKmYrwpWaLyEtucq3jwUEB7jD5Niwsx4B63uf8yeYBS2mEGSTlYmUEKC6m31QSN4K2Xc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781716494; c=relaxed/simple; bh=kFemRanvc6E5S6TRcsxsOq/DYjRukGgE0QCE4X4i0ms=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:Subject:From:To: References:In-Reply-To; b=cRoBnQFhccCjH6QmQ6J1kZYKwkaxnnKVSwKboBX00xHkodJgRdl+pjJqdSrKJPB8/y1QcWoPtGyNnbuWc0qvD8uYZIPK9LIcdkOHEaiy1IGnyTwwk55x8WfM2h+EfRVvh1GTzReWUZr0IWr3b8xrOv95/aYp8sEpTnNmEJ6vpNw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=URPUI+Kx; arc=none smtp.client-ip=95.215.58.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="URPUI+Kx" Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1781716477; h=from:from: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; bh=y5SZXXiFJ8ueBXhlsGQFJZi5a2AW4j8ADP8QWnx4K3E=; b=URPUI+KxX5k2L3dXRV6rad5ag+FPQQaxDxIUK7ydK6ENuc2D6h+cIasadvkr9vZSYWnBoB gzeq9d5VdvLRYjMeOEE4YFmBzQPOgS1Wb2XFmG/AhqYDEwxEpT43tx40GKKgRY54XN7e+t WtLX3QXOtLqSfo09anHRSIUsBplrdXs= Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Wed, 17 Jun 2026 17:14:23 +0000 Message-Id: Cc: "Brendan Jackman" , "Andrew Morton" , "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" , "Alexei Starovoitov" , "Harry Yoo (Oracle)" , "Gregory Price" , , , , "Hao Ge" Subject: Re: [PATCH] mm/page_alloc: unify __alloc_frozen_pages[_nolock]_noprof() X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: "Brendan Jackman" To: "Suren Baghdasaryan" , "Vlastimil Babka (SUSE)" References: <20260617-alloc-trylock-v1-1-83fd7858832e@google.com> <2399b3ad-4eac-4a14-94c3-27e9f07972a1@kernel.org> In-Reply-To: X-Migadu-Flow: FLOW_OUT On Wed Jun 17, 2026 at 4:49 PM UTC, Suren Baghdasaryan wrote: > On Wed, Jun 17, 2026 at 9:39=E2=80=AFAM Vlastimil Babka (SUSE) > wrote: >> >> +Cc Alexei >> >> On 6/17/26 17:29, Brendan Jackman wrote: >> > Currently the core allocator code is controlled by ALLOC_NOLOCK, but t= he >> >> It's not, it's ALLOC_TRYLOCK! Thanks for proving that we need to rename = it >> to ALLOC_NOLOCK: >> >> https://lore.kernel.org/all/DJ9QPTO2WXNB.10E88ZHWRDHB0@gmail.com/ >> >> So you just won the job to do the rename :) I think it should be done be= fore >> this patch, so that the new usages and other _trylock names introduced h= ere >> can be done as _nolock outright. Ack. I'll aim to send that tomorrow once Sashiko has caught up. >> > 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 onl= y >> > 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. >> > >> > 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, a= nd >> > only flags that affect the slowpath get changed here. >> > >> > b. Application of current_gfp_context() - also only affects the >> > slowpath >> > >> > 3. The slowpath itself: this is now just explicitly skipped under >> > !ALLOC_TRYLOCK. >> >> I'll have to ponder it more closely. >> >> > Ulterior motive: adding an alloc_flags arg to the allocator's >> > mm-internal entrypoint can later be used to do more allocation >> > customisation without needing to create new GFP flags. >> >> Ack. > > I think this change might also help us in removing __GFP_NO_CODETAG Nice, this actually looks trivial? I can probably just tack it onto the v2 for this patch/series. > introduced in [1] and being the only user of __GFP_NO_OBJ_EXT once > Vlastimil's patchset removing other __GFP_NO_OBJ_EXT users lands. > CC'ing Hao as he is brainstorming ways to remove __GFP_NO_CODETAG, and > this might be the answer. >> >> Besides the need to ponder unintended effects, mostly LGTM. Just not a f= an >> of the hardcoded '0' passed at various places. In the slab variant of th= is >> (the thread I've linked above) I went with SLAB_ALLOC_DEFAULT, so you ca= n do >> e.g. ALLOC_DEFAULT here? Yup ALLOC_DEFAULT sounds fine to me. Thanks for the reviews as always.