On Fri 31-05-19 08:22:06, Michal Hocko wrote: > On Fri 31-05-19 08:04:01, Michal Hocko wrote: > > [Please always Cc linux-api mailing list (now added) when adding a new > > user visible API. Keeping the rest of the email intact for reference] > > > > On Thu 30-05-19 17:26:33, semenzato@xxxxxxxxxxxx wrote: > > > From: Luigi Semenzato <semenzato@xxxxxxxxxxxx> > > > > > > Report separate components (anon, file, and shmem) > > > for PSS in smaps_rollup. > > > > > > This helps understand and tune the memory manager behavior > > > in consumer devices, particularly mobile devices. Many of > > > them (e.g. chromebooks and Android-based devices) use zram > > > for anon memory, and perform disk reads for discarded file > > > pages. The difference in latency is large (e.g. reading > > > a single page from SSD is 30 times slower than decompressing > > > a zram page on one popular device), thus it is useful to know > > > how much of the PSS is anon vs. file. > > Could you describe how exactly are those new counters going to be used? > > I do not expect this to add a visible penalty to users who are not going > to use the counter but have you tried to measure that? Also forgot to mention that any change to smaps should be documented in Documentation/filesystems/proc.txt. -- Michal Hocko SUSE Labs
