On Tue, Oct 19, 2010 at 11:59 AM, KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > On Tue, 19 Oct 2010 10:07:38 +0800 > "Figo.zhang" <zhangtianfei@xxxxxxxxxxxxxxxx> wrote: > >> >> > >> > very lots of change ;) >> > can you please send us your crash log? >> >> i add some prink in select_bad_process() and oom_badness() to see >> pid/totalpages/points/memoryuseage/and finally process to selet to kill. >> >> i found it the oom-killer select: syslog-ng,mysqld,nautilus,VirtualBox >> to kill, so my question is: >> >> 1. the syslog-ng,mysqld,nautilus is the system foundamental process, so >> if oom-killer kill those process, the system will be damaged, such as >> lose some important data. >> >> 2. the new oom-killer just use percentage of used memory as score to >> select the candidate to kill, but how to know this process to very >> important for system? >> > > The kernel can never know it. Just an admin (a man or management software) knows. > Old kernel tries to guess it, but it tend to be wrong and many many report comes > "why my ....is killed..." All guesswork the kernel does is not enough, I think. > >> oom_score_adj, it is anyone commercial linux distributions to use this >> to protect the critical process. >> > oom_adj may be used in some system. All my customers select panic_at_oom=1 > and cause cluster fail over rather than half-broken. > > <Off topic> > Your another choice is memory cgroup, I think. > please see documentation/cgroup/memory.txt or libcgroup. > http://sourceforge.net/projects/libcg/ > You can use some fancy controls with it. > </Off topic> > > > BTW, there seems to be some strange things. > (CC'ed to linux-mm) > Brief Summary: > an oom-killer happens on swapless environment with 2.6.36-rc8. > It has 2G memory. > a reporter says > == >> i want to test the oom-killer. My desktop (Dell optiplex 780, i686 >> kernel)have 2GB ram, i turn off the swap partition, and open a huge pdf >> files and applications, and let the system eat huge ram. >> >> in 2.6.35, i can use ram up to 1.75GB, >> >> but in 2.6.36-rc8, i just use to 1.53GB ram , the system come very slow >> and crashed after some minutes , the DiskIO is very busy. i see the >> DiskIO read is up to 8MB/s, write just only 400KB/s, (see by conky). > == > > The trigger of oom-kill is order=0 allocation. (see original mail for full log) > > > Oct 19 09:44:08 myhost kernel: [ 618.441470] httpd invoked oom-killer: > gfp_mask=0x201da, order=0, oom_adj=0, oom_score_adj=0 > > Zone's stat is. > > Oct 19 09:44:08 myhost kernel: [ 618.441551] > DMA free:7968kB min:64kB low:80kB high:96kB active_anon:3700kB inactive_anon:3752kB > active_file:12kB inactive_file:252kB unevictable:0kB isolated(anon):0kB > isolated(file):0kB present:15788kB mlocked:0kB dirty:0kB writeback:4kB > mapped:52kB shmem:348kB slab_reclaimable:0kB slab_unreclaimable:16kB > kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB > writeback_tmp:0kB pages_scanned:421 all_unreclaimable? yes > lowmem_reserve[]: 0 865 1980 1980 > > Oct 19 09:44:08 myhost kernel: [ 618.441560] > Normal free:39348kB min:3728kB low:4660kB high:5592kB active_anon:176740kB > inactive_anon:25640kB active_file:84kB inactive_file:308kB > unevictable:0kB isolated(anon):0kB isolated(file):0kB present:885944kB > mlocked:0kB dirty:0kB writeback:4kB mapped:576992kB shmem:5024kB > slab_reclaimable:7612kB slab_unreclaimable:15512kB kernel_stack:2792kB > pagetables:6884kB unstable:0kB bounce:0kB writeback_tmp:0kB > pages_scanned:741 all_unreclaimable? yes > lowmem_reserve[]: 0 0 8921 8921 > > Oct 19 09:44:08 myhost kernel: [ 618.441569] > HighMem free:392kB min:512kB low:1712kB high:2912kB active_anon:492208kB > inactive_anon:166404kB active_file:180kB inactive_file:840kB > unevictable:40kB isolated(anon):0kB isolated(file):0kB present:1141984kB > mlocked:40kB dirty:0kB writeback:12kB mapped:493648kB shmem:72216kB > slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB > pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB > pages_scanned:1552 all_unreclaimable? yes > > Highmem seems a bit strange. > present(1141984) - active_anon - inactive_anon - inactive_file - active_file > = 482352kB but free is 392kB. > > Highmem is used for some other purpose than usual user's page.(pagetable is 0.) > And, Hmm, mapped:493648kB seems too large for me. > (active/inactive-file + shmem is not enough.) > And "mapped" in NORMAL zone is large, too. > > Does anyone have idea about file-mapped-but-not-on-LRU pages ? Isn't it possible some file pages are much sharable? Please see the page_add_file_rmap. > > Thanks, > -Kame > > > > > > > -- > 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/ . > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> > > -- Kind regards, Minchan Kim -- 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/ . Don't email: <a href