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Sun, 26 Oct 2025 21:07:57 -0700 (PDT) MIME-Version: 1.0 References: <20251026100159.6103-1-laoar.shao@gmail.com> <20251026100159.6103-5-laoar.shao@gmail.com> In-Reply-To: <20251026100159.6103-5-laoar.shao@gmail.com> From: Barry Song <21cnbao@gmail.com> Date: Mon, 27 Oct 2025 12:07:45 +0800 X-Gm-Features: AWmQ_bnqDQ_nqt4D6_uisIDfd46Kja53Wh7oCLWwA2TUqJRp3ILNLRZozn7IGYE Message-ID: Subject: Re: [PATCH v12 mm-new 04/10] mm: thp: decouple THP allocation between swap and page fault paths To: Yafang Shao Cc: akpm@linux-foundation.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, david@redhat.com, lorenzo.stoakes@oracle.com, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, ziy@nvidia.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, hannes@cmpxchg.org, usamaarif642@gmail.com, gutierrez.asier@huawei-partners.com, willy@infradead.org, ameryhung@gmail.com, rientjes@google.com, corbet@lwn.net, shakeel.butt@linux.dev, tj@kernel.org, lance.yang@linux.dev, rdunlap@infradead.org, clm@meta.com, bpf@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: n441zqoqg77e7wtuxi4oiphq463k4d6x X-Rspamd-Queue-Id: 61AA68000E X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1761538078-571139 X-HE-Meta: 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 Q2HQGTFM 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sun, Oct 26, 2025 at 6:02=E2=80=AFPM Yafang Shao = wrote: > > The new BPF capability enables finer-grained THP policy decisions by > introducing separate handling for swap faults versus normal page faults. > > As highlighted by Barry: > > We=E2=80=99ve observed that swapping in large folios can lead to more > swap thrashing for some workloads- e.g. kernel build. Consequently, > some workloads might prefer swapping in smaller folios than those > allocated by alloc_anon_folio(). > > While prtcl() could potentially be extended to leverage this new policy, > doing so would require modifications to the uAPI. > > Signed-off-by: Yafang Shao > Reviewed-by: Lorenzo Stoakes > Acked-by: Usama Arif > Cc: Barry Song <21cnbao@gmail.com> Thanks for addressing this. Acked-by: Barry Song Thanks Barry