Huan Yang <link@xxxxxxxx> writes: > 在 2023/11/9 18:39, Michal Hocko 写道: >> [Some people who received this message don't often get email from mhocko@xxxxxxxx. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] >> >> On Thu 09-11-23 18:29:03, Huan Yang wrote: >>> HI Michal Hocko, >>> >>> Thanks for your suggestion. >>> >>> 在 2023/11/9 17:57, Michal Hocko 写道: >>>> [Some people who received this message don't often get email from mhocko@xxxxxxxx. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] >>>> >>>> On Thu 09-11-23 11:38:56, Huan Yang wrote: >>>> [...] >>>>>> If so, is it better only to reclaim private anonymous pages explicitly? >>>>> Yes, in practice, we only proactively compress anonymous pages and do not >>>>> want to touch file pages. >>>> If that is the case and this is mostly application centric (which you >>>> seem to be suggesting) then why don't you use madvise(MADV_PAGEOUT) >>>> instead. >>> Madvise may not be applicable in this scenario.(IMO) >>> >>> This feature is aimed at a core goal, which is to compress the anonymous >>> pages >>> of frozen applications. >>> >>> How to detect that an application is frozen and determine which pages can be >>> safely reclaimed is the responsibility of the policy part. >>> >>> Setting madvise for an application is an active behavior, while the above >>> policy >>> is a passive approach.(If I misunderstood, please let me know if there is a >>> better >>> way to set madvise.) >> You are proposing an extension to the pro-active reclaim interface so >> this is an active behavior pretty much by definition. So I am really not >> following you here. Your agent can simply scan the address space of the >> application it is going to "freeze" and call pidfd_madvise(MADV_PAGEOUT) >> on the private memory is that is really what you want/need. > There is a key point here. We want to use the grouping policy of memcg > to perform > proactive reclamation with certain tendencies. Your suggestion is to > reclaim memory > by scanning the task process space. However, in the mobile field, > memory is usually > viewed at the granularity of an APP. > > Therefore, after an APP is frozen, we hope to reclaim memory uniformly > according > to the pre-grouped APP processes. > > Of course, as you suggested, madvise can also achieve this, but > implementing it in > the agent may be more complex.(In terms of achieving the same goal, > using memcg > to group all the processes of an APP and perform proactive reclamation > is simpler > than using madvise and scanning multiple processes of an application > using an agent?) I still think that it's not too complex to use process_madvise() to do this. For each process of the application, the agent can read /proc/PID/maps to get all anonymous address ranges, then call process_madvise(MADV_PAGEOUT) to reclaim pages. This can even filter out shared anonymous pages. Does this work for you? -- Best Regards, Huang, Ying
