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AJvYcCW5QaYWAwpVpLGgbr61N9Ibug+zVEtXPLiYOjpBFaEdFaCmvyuHLANmcoTfrqZ8NUBvDSUJl3Xkwg==@kvack.org X-Gm-Message-State: AOJu0YzN4P6m2KYIQeZicqmD8eeNO9mkZD9Yjx55/xU4Fx4k7/7vvgUk 0S8voKzrM5O1RbUkggOxdTGr4jSm62fztuIFf8iRKSw9ATFYKuEZMt6MNTquCiPoBdGbsCLigKf mz/Mb1IRHViw+jMeo08eUX+k1zjzEU1c= X-Gm-Gg: ASbGnctJz8DBP60LBZS/X+Vh3ryRhC/sg2PONN5d7tXgDZwKSu8nDlN+onEd/owEpiD DoraG9wrX1kZvt/SNG4cyTnbcmtieDxmFEVNlMQ5pcPWb8RSz++HdbG/bTE9iYIoaQjTQMYUj9p sgusnfpASjSrnmHYE6WTQuwr4j52cUDpIqCDHKfk/LQ/XAxTND4SuIq4CKEpYWPb2+lLlmeyJX9 G9M0CPSmozRWazKdKF1c6yxxb49w1aDIIM9ZVhN X-Google-Smtp-Source: AGHT+IEIM2EgMj1lrnPfc/QLZaI/SIuaTUMHPn65O0erOt+9ClYGQVe1+p6+wCBP890WHjKTvNzMiK21AyXb7Ep4gFQ= X-Received: by 2002:ad4:5cad:0:b0:70d:6df3:9a88 with SMTP id 6a1803df08f44-70d973f45e1mr137706786d6.56.1756210045540; Tue, 26 Aug 2025 05:07:25 -0700 (PDT) MIME-Version: 1.0 References: <20250826071948.2618-1-laoar.shao@gmail.com> <0398bfc4-49f5-4a7c-abba-90151002ff82@lucifer.local> In-Reply-To: <0398bfc4-49f5-4a7c-abba-90151002ff82@lucifer.local> From: Yafang Shao Date: Tue, 26 Aug 2025 20:06:49 +0800 X-Gm-Features: Ac12FXw1g5xEZf3xxD5gs1s1dLXr_RGo94IW44IbmphAAO8l9ciefTUsmal1AOk Message-ID: Subject: Re: [PATCH v6 mm-new 00/10] mm, bpf: BPF based THP order selection To: Lorenzo Stoakes Cc: David Hildenbrand , akpm@linux-foundation.org, 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, 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-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 9526140011 X-Stat-Signature: fnqqctne1wmgzx8u5i5jdxy1f9xi5ejp X-HE-Tag: 1756210046-397503 X-HE-Meta: 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 0sneLYub 2S5B0dVE2Bb5lF3RkrPjemXocLFjGzh3bNZHdgYTjX+lV3VvLyzc6hCXANT/XMH4+0+aPoHCydx2tgYqDU0Tb+jYicSB4+1eESrpc300JVA+TsaCQA/6RD1Nb/mtDQEIM6UTidEGuPX9G51Ds7DudqxCsxyXYl+ckwIgOpBPs+DNVM4hiWyys3slvXs/bn8COj8NS/SO/xPk/Wzhsv0mfM6pUaqdipaPefP8HrEq7v5K32rdSR+YpmJ9xId+CZFPZqGb5xSYH7geqDNsA5+K1NaHnSvWUoTp3SmT3FCdDTgJe4fMXJxL65NP+D6HGz6vXrE8E/RUriNpB0VVlGTp/iZ0CepsR1YtBwq64jcmEkLM1OPM4nKzP8OKU0HjGqCeiTCsL7gU/R4xhcl0RrsvQm6Oks0zFYS9wcAYn 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 Tue, Aug 26, 2025 at 4:33=E2=80=AFPM Lorenzo Stoakes wrote: > > On Tue, Aug 26, 2025 at 09:42:30AM +0200, David Hildenbrand wrote: > > On 26.08.25 09:19, Yafang Shao wrote: > > > Background > > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > > > > > Our production servers consistently configure THP to "never" due to > > > historical incidents caused by its behavior. Key issues include: > > > - Increased Memory Consumption > > > THP significantly raises overall memory usage, reducing available = memory > > > for workloads. > > > > > > - Latency Spikes > > > Random latency spikes occur due to frequent memory compaction trig= gered > > > by THP. > > > > > > - Lack of Fine-Grained Control > > > THP tuning is globally configured, making it unsuitable for contai= nerized > > > environments. When multiple workloads share a host, enabling THP w= ithout > > > per-workload control leads to unpredictable behavior. > > > > > > Due to these issues, administrators avoid switching to madvise or alw= ays > > > modes=E2=80=94unless per-workload THP control is implemented. > > > > > > To address this, we propose BPF-based THP policy for flexible adjustm= ent. > > > Additionally, as David mentioned [0], this mechanism can also serve a= s a > > > policy prototyping tool (test policies via BPF before upstreaming the= m). > > > > There is a lot going on and most reviewers (including me) are fairly bu= sy > > right now, so getting more detailed review could take a while. > > > > This topic sounds like a good candidate for the bi-weekly MM alignment > > session. > > > > Would you be interested in presenting the current bpf interface, how to= use > > it, drawbacks, todos, ... in that forum? > > > > David Rientjes, who organizes this meeting, is already on Cc. > > If we do this, would like an invite to it also! > > Have been meaning to take a look into this in detail while in RFC but mor= e so > now obviously :) as discussed in THP cabal, I am broadly in favour of thi= s as > long we get the interface right. > > Anyway let me have a look through...! Thanks in advance. --=20 Regards Yafang