On Tue, Mar 29, 2011 at 6:16 PM, KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> wrote: > Hi > > sorry, I didn't see past discussion of this thread. then, I may be missing > something. > >> Two new stats in per-memcg memory.stat which tracks the number of >> page faults and number of major page faults. >> >> "pgfault" >> "pgmajfault" >> >> They are different from "pgpgin"/"pgpgout" stat which count number of >> pages charged/discharged to the cgroup and have no meaning of reading/ >> writing page to disk. >> >> It is valuable to track the two stats for both measuring application's >> performance as well as the efficiency of the kernel page reclaim path. >> Counting pagefaults per process is useful, but we also need the aggregated >> value since processes are monitored and controlled in cgroup basis in memcg. > > Currently, memory cgroup don't restrict number of page fault. And we already have > this feature by CONFIG_CGROUP_PERF if my understanding is correct. Why don't you > use perf cgroup? > > In the other words, after your patch, we have four pagefault counter. Do we > really need *four*? Can't we consolidate them? > > 1. tsk->maj_flt > 2. perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ) > 3. count_vm_event(PGMAJFAULT); > 4. mem_cgroup_count_vm_event(PGMAJFAULT); The first three are per-process and per-system level counters. What I did in this patch is to add per-memcg counters for pgfault and pgmajfault. This purpose is not to do any limiting but monitoring. I am not sure about the CONFIG_CGROUP_PERF, does it require CONFIG_PERF_EVENTS? Thanks --Ying > > > > > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>