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AJvYcCWPRpxF7PgW+5RST24XosVUzBptazpdQ952iPhrLT03eu9UayB3d2En9doXj10fBtdzOs9fnpyY3g==@kvack.org X-Gm-Message-State: AOJu0YxHmQF0pbx9Bj2OvSmpYtLC8Tk6oXWgZ3aE7RdoBl1AD/sgC9VI XXIMiZ7D5TUGbUrkS10s8jO5tXDYwdWVKU23Ps/e32MHqmtkflOoC02xH+B307rZgEWGeSylxmv gNL2Bv9OqkHfACf12NWcv1lKYIrCkJe32qVteK8ej X-Gm-Gg: ASbGncuqjFy8V7RCTbroeNOBHEYtrUAwnLtM0ogjh/xe+fuHGaNT0yS4+9SXF2BQEh3 J+1hmtB3cDXTdtVMI6IuNxZu6mdfXwZyE4B+PPaSN9sflRo/1wka1pNwvs9s0Mhm94ZsAz3u1td +7/zoOmkcwkKGotxR1XONddr76BDUs9XIiRy9CRa6GS1aJQRxIJq/lMERhPz6cWxvcGQGvM+40H fo2dAi36kU41I0taacRnWflL8KHPxFtif3O2Q== X-Google-Smtp-Source: AGHT+IEsDSi8OkW3pGhx0kurDkEYKeTjeHF2pizFwIotQyNcJvMlToKfbMqC1EaLyBr5Mr/rFszOK4D2GukeMpu05bg= X-Received: by 2002:a17:902:ebcb:b0:235:7c6:ebd2 with SMTP id d9443c01a7336-23e25730056mr376366275ad.31.1753208871268; Tue, 22 Jul 2025 11:27:51 -0700 (PDT) MIME-Version: 1.0 References: <20250722071146.48616-1-daniel.sedlak@cdn77.com> In-Reply-To: From: Kuniyuki Iwashima Date: Tue, 22 Jul 2025 11:27:39 -0700 X-Gm-Features: Ac12FXxLpxDEFMJ1OteDYmd2L-tyFGpDS0pkCtWi7bSCC4GD2tBgGIdi0vnLq7g Message-ID: Subject: Re: [PATCH v3] memcg: expose socket memory pressure in a cgroup To: Shakeel Butt Cc: =?UTF-8?Q?Michal_Koutn=C3=BD?= , Daniel Sedlak , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Jonathan Corbet , Neal Cardwell , David Ahern , Andrew Morton , Yosry Ahmed , linux-mm@kvack.org, netdev@vger.kernel.org, Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , cgroups@vger.kernel.org, Matyas Hurtik Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 87A271A0005 X-Rspam-User: X-Rspamd-Server: rspam09 X-Stat-Signature: 1p7iwn357ixd7b3o3s5r1ir33iaw1pxo X-HE-Tag: 1753208872-400193 X-HE-Meta: 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 M/+qzMxQ Ttl7QEMWig73j6G63Hp9ek3eTkgwxNgxSel9rSJNNha9/cz3h9A01qSLxDE64ck65brvgiFw+suQKgjFGxb44HKgD3SI5g/IjixF9/sXv2RY6D9BWnp5IBG3VWxpQcd9Fui2/oLaGD1EJvubLum0aB8ntAU9hWYnrAOzJZyrNIiMpVS10eFLmRRVJHFsUay8ymLVi6/aTLCwCaeHfqhC20xv6ln/0xdMW/Gn9QeDJPPIcZLNXFtLT11hCClkgjmBZ8dENM0FXDKXNb4jokSYKGgYse1oVmd4W/bB6ftIKPUYr3S0ovkRMi5xKTi/zA6CoCb5U 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, Jul 22, 2025 at 10:50=E2=80=AFAM Shakeel Butt wrote: > > On Tue, Jul 22, 2025 at 10:57:31AM +0200, Michal Koutn=C3=BD wrote: > > Hello Daniel. > > > > On Tue, Jul 22, 2025 at 09:11:46AM +0200, Daniel Sedlak wrote: > > > /sys/fs/cgroup/**//memory.net.socket_pressure > > > > > > The output value is an integer matching the internal semantics of the > > > struct mem_cgroup for socket_pressure. It is a periodic re-arm clock, > > > representing the end of the said socket memory pressure, and once the > > > clock is re-armed it is set to jiffies + HZ. > > > > I don't find it ideal to expose this value in its raw form that is > > rather an implementation detail. > > > > IIUC, the information is possibly valid only during one jiffy interval. > > How would be the userspace consuming this? > > > > I'd consider exposing this as a cummulative counter in memory.stat for > > simplicity (or possibly cummulative time spent in the pressure > > condition). > > > > Shakeel, how useful is this vmpressure per-cgroup tracking nowadays? I > > thought it's kind of legacy. > > > Yes vmpressure is legacy and we should not expose raw underlying number > to the userspace. How about just 0 or 1 and use > mem_cgroup_under_socket_pressure() underlying? In future if we change > the underlying implementation, the output of this interface should be > consistent. But this is available only for 1 second, and it will not be useful except for live debugging ?