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AJvYcCX83kaova7+Sl/heVZxJPaopmrFThVEd3FJ+QHhq/DBK5uFHEMgPzf6sbczCasoA9EISjvkYoD0yQ==@kvack.org X-Gm-Message-State: AOJu0YxlrHNGVK5ED3/cWF//QaA5BgC2a9RMSFJd+mEQcdICZsDjZOo5 8uL+xaLqyxVHtUj6/Eb757xpShAYXoNByNINTThSEskznPbP7aeeEO4wcLVWMlqNMBfKoyT0VBB 08y4nj2KaqaTIXfSWl/EZMRPPmU7mKUY= X-Gm-Gg: ASbGncvrGqY/ybB3d7bK0XEWyeTCyDJ9kCX5DKp1nt8Ov+nXL+EQS5c0SRHzMOxf7jI NjPzhU8SqA14no7sulx6J3KopScbFq4+qDdY2WDurXKf6fTDvAaFuFTfG+6DglpYYtkn/IVWvmO nSQurGHxZpwD8uD+h8XBJ6T0u088M837Dqvd6yRWmOY71yQuJpqiZs/AGpRPwK1KN3/UOJfdFNs 03NzlC+07jDyhXwBav0qDP30lih+PJuGXdq8x5k X-Google-Smtp-Source: AGHT+IFmxWKlg9lTecPzrdzZLK0pJmBN7ltgoRVqWwQIeIm/S78B3/KreguC5TVAusVGlC2xM1N4WcQu5sVexX82BM8= X-Received: by 2002:a05:6214:262d:b0:753:c7a0:8dbd with SMTP id 6a1803df08f44-767c50647c1mr23734096d6.65.1757661674807; Fri, 12 Sep 2025 00:21:14 -0700 (PDT) MIME-Version: 1.0 References: <20250910024447.64788-1-laoar.shao@gmail.com> <20250910024447.64788-4-laoar.shao@gmail.com> <0aad915f-80b1-4c2f-adcd-4b4afe5b17dc@lucifer.local> In-Reply-To: <0aad915f-80b1-4c2f-adcd-4b4afe5b17dc@lucifer.local> From: Yafang Shao Date: Fri, 12 Sep 2025 15:20:38 +0800 X-Gm-Features: AS18NWAEu23WLC4-YzUUQ5p8sE8322qhir0Y_VCH3XGQPacrY3qmhSJ5JIg6_ao Message-ID: Subject: Re: [PATCH v7 mm-new 03/10] mm: thp: decouple THP allocation between swap and page fault paths To: Lorenzo Stoakes Cc: akpm@linux-foundation.org, david@redhat.com, ziy@nvidia.com, baolin.wang@linux.alibaba.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, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, ameryhung@gmail.com, rientjes@google.com, corbet@lwn.net, 21cnbao@gmail.com, shakeel.butt@linux.dev, bpf@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: CC8D314000D X-Stat-Signature: phsuc9u8si9p6qkqyf74gdbdeubd5had X-Rspam-User: X-HE-Tag: 1757661675-25881 X-HE-Meta: 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 UqfAcExu Lulli/lXorH8OIAl+ZLnUQaQ9Ncg4gRqny9KyC+XYgOKynjn+TXldo6bZS/HGNSQG25GR+jWvRIiqso35I+xgu1Y23kvL31wHEeY+bSzdf8rVru0ERDpc1bhwOiizlNSnavDyEs+Le7GC4RUN0bYnl45nFVOj+PPSCS2wcmdvceKtv6MTonopb3XFSJVGDAdTeZhblQGT1VkYj0zF/GnbvluPf8JPaZ6EeZJLR5oov3AoO4LUAe1Ir31c3RLtBKl46QCWgSNz/Vvyv1zC0GMWdTSm7gZ9ueTG+JDI0zYRCn3nA+WhP0ZJDYnEIx5BSAwa2lUX4OBGNikVxu7POdr4Hm3ljVj+JnSfT511Rh0lnsEh/lUO915Cbrh9FfDg5+ubSrE6EZ4bLcF/y3jY5zSrTwNHW9RMPwFh0VENxKEBI5GYCZPFV0zjVZjkrw== 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 Thu, Sep 11, 2025 at 10:56=E2=80=AFPM Lorenzo Stoakes wrote: > > On Wed, Sep 10, 2025 at 10:44:40AM +0800, 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 > > Other than nits, these seems fine, so: > > Reviewed-by: Lorenzo Stoakes > > > Cc: Barry Song <21cnbao@gmail.com> > > --- > > include/linux/huge_mm.h | 3 ++- > > mm/huge_memory.c | 2 +- > > mm/memory.c | 2 +- > > 3 files changed, 4 insertions(+), 3 deletions(-) > > > > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h > > index f72a5fd04e4f..b9742453806f 100644 > > --- a/include/linux/huge_mm.h > > +++ b/include/linux/huge_mm.h > > @@ -97,9 +97,10 @@ extern struct kobj_attribute thpsize_shmem_enabled_a= ttr; > > > > enum tva_type { > > TVA_SMAPS, /* Exposing "THPeligible:" in smaps. */ > > - TVA_PAGEFAULT, /* Serving a page fault. */ > > + TVA_PAGEFAULT, /* Serving a non-swap page fault. */ > > TVA_KHUGEPAGED, /* Khugepaged collapse. */ > > TVA_FORCED_COLLAPSE, /* Forced collapse (e.g. MADV_COLLAPSE). = */ > > + TVA_SWAP, /* Serving a swap */ > > Serving a swap what? :) I think TVA_SWAP_PAGEFAULT would be better here r= ight? > And 'serving a swap page fault'. will change it. Thanks for your suggestion. --=20 Regards Yafang