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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 References: <20250722071146.48616-1-daniel.sedlak@cdn77.com> <4g63mbix4aut7ye7b7s4m5q7aewfxq542i2vygniow7l5a3zmd@bvis5wmifscy> Content-Language: en-US From: Daniel Sedlak In-Reply-To: <4g63mbix4aut7ye7b7s4m5q7aewfxq542i2vygniow7l5a3zmd@bvis5wmifscy> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CTCH: RefID="str=0001.0A00211C.6880A03E.0039,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0"; Spam="Unknown"; VOD="Unknown" X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: F200C40008 X-Stat-Signature: nerdxz44agmgfn14mge8ttuf7y9xehfs X-HE-Tag: 1753260094-80407 X-HE-Meta: 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 2UpfA3KT Wipwy9EexZ9442/AR5I1w9QSIZnTGLNTnZYospTv8l9DnxmEbhdCYMtB/n6TYjUu+vY5Pl9uWjnbV6EY3r/tMxCRzV+E6/c3W7G99+fayXqovVPAztEC1v4IXUvFeH9zSpuSbkgQaMAANveqsxUeVzKuMcRB1sB3/WRbac1GGjjhDMywURhWgU8/WuSWShf3j2PZ8ap7/ONR0MB6ApuOXjpq7u5jacfw2nsr3nGwp5eLXuHu6DsJeHjzju71zZQogZYkqyrJJ3tFSO4Cyefuwr+flPsKMWtSSiIRR5K1UXEEET7Ujbgyxlqg3sQOPxNljrqPsNFtpNj6rlsdWIK2EqDxt4tHuktMaU2pe 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 7/22/25 9:05 PM, Shakeel Butt wrote: > On Tue, Jul 22, 2025 at 11:27:39AM -0700, Kuniyuki Iwashima wrote: >> On Tue, Jul 22, 2025 at 10:50 AM Shakeel Butt wrote: >>> >>> On Tue, Jul 22, 2025 at 10:57:31AM +0200, Michal Koutný 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 ? > > 1 second is the current implementation and it can be more if the memcg > remains in memory pressure. In our production environment, when this so-called pressure happens, it typically stays under pressure for a few hours straight. So, in our scenario, even a 1 or 0 would be helpful since it does not oscillate.