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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 X-Rspamd-Queue-Id: 41B84140005 X-Stat-Signature: noie9sft6b4cwwc4g6ddt4fyuoan19iq X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1781716480-823140 X-HE-Meta: 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 fSZp3isi 0FUc1tvvhCv0toiH28d67CgOSPKwXrSWa6SwgL4/MGAEEBfrbkGURFkffxV08jEgmZLVpZXCebmayYeDNwy49D4boEJwQsGOB3E1s3Dh4IVSSRjQo/Pag4QV8uGYa1CKane8p1KUYEyjDE+OrQzXoFthxWpqesx4tde2fdOys+I8AJjlrS2wjSLwJt2T4DFlqmvK39HVPE3LeHDC5Dw/fkglkpXuqpyNv2eLM20XegugFydu53AWS2YgEpQlxk5ULYlLb6NBa6Eo/4Eqb/mfvlZb2SBWNE+3y7I0T9kvc/SDOqHUOWebGobHlOeV1jFhh6eQGHgwBAZrCThUERHO19oskkXvs4dCVqbrdgzm/uNBcoqj65lUSsAsIaP92bx9n5ml3FQv1e9TtQEEQnuF5y6a7gA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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.