From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-183.mta0.migadu.com (out-183.mta0.migadu.com [91.218.175.183]) (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 22FB040D56B for ; Wed, 24 Jun 2026 16:24:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.183 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782318264; cv=none; b=VlCU1EFQSkLTUg5uDk4PciRszmqC7vwEiRnZVSCIoU1Kbq38QU7So9vDqX2jxAciehe4LhGIzLlyQeMTIBdm0bSLdQe/kDrY0jnzA155Y8wSVAcF5PU5h8BzHnnxTbjDnZjHKOjdXl2T0CLpUMtcYiY6qr5XGa/kCnY43nZpsko= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782318264; c=relaxed/simple; bh=pIX/mM3PQMYGUaXlw5O3DtlmpIS9XfSE+7CEFFkIjzI=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:Subject:From:To: References:In-Reply-To; b=XcEgMPp23K6W1QqtmPwbQeZQHdgD+XVQdGWBPPQ0ZKQKus/RlYGI5I+9a7XV78ZgMqxUJu+Ffaubl3x6kh5eN4BFuy54lSBGIlKD+xlzHkC91A99rSYwfa+340F8Rs8Sd+E0/z0+DffzOjuwrXEMexuVmPGoqNAIUcwUBMzJdPY= 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=qFHnevJg; arc=none smtp.client-ip=91.218.175.183 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="qFHnevJg" 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=1782318259; 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=oCSclJsOHXGUR9PPnNQt/KSxQU5CDN7d+xhXrFSXdFQ=; b=qFHnevJgDyc87ZrZY47VjxEqXA89BZaLQJxeubOA8i6wlCnoxO1zxlqexltOhiSP1mJ1B7 otStABHF1E7ajWjm02PBOzJDLYTFmB365svZ3sgHi6JJ9ZFyOhdWfqGltg8SQnpX4PCV4w VoKCdKXbZAf/1znIe0ErC4bci6VBduY= Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Wed, 24 Jun 2026 16:24:16 +0000 Message-Id: Cc: "Andrew Morton" , "Vlastimil Babka" , "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" , "Harry Yoo (Oracle)" , "Gregory Price" , "Alexei Starovoitov" , "Matthew Wilcox" , , , Subject: Re: [PATCH v2 03/13] 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" , "Brendan Jackman" References: <20260622-alloc-trylock-v2-0-31f31367d420@google.com> <20260622-alloc-trylock-v2-3-31f31367d420@google.com> In-Reply-To: X-Migadu-Flow: FLOW_OUT On Wed Jun 24, 2026 at 4:00 PM UTC, Suren Baghdasaryan wrote: > On Mon, Jun 22, 2026 at 3:02=E2=80=AFAM 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. >> >> 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. >> >> b. Application of current_gfp_context() - also only affects the >> slowpath >> >> 3. The slowpath itself: this is now just explicitly skipped under >> !ALLOC_TRYLOCK. >> >> 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. > > Looks like a nice overall cleanup. > >> >> While adding this flag to a bunch of places, create ALLOC_DEFAULT to >> avoid a mysterious literal 0 in most places. alloc_frozen_pages_noprof() >> is defined above the alloc flags so just leave that as a slightly messy >> exception instead of trying to fully reorder mm/internal.h for that one >> case. > > Moving the whole alloc_frozen_pages() block down seems simple enough > and would avoid special-casing this. Yeah... when you put it like that, I don't actually know why I was so intimidated by the prospect of moving a handful of function declarations! Anyway in the v3 I'm creating a new mm/page_alloc.h so this will happen as a side effect of that.