Hi, Minchan Kim Thanks for your analysis and suggestion! I'm not familiar with COMPACTION. Does it work with ARM? Does it require specific MMU configuration? Notice that it depends on HUGETLB_PAGE On Wed, Apr 20, 2011 at 12:47 PM, Minchan Kim <minchan.kim@xxxxxxxxx> wrote: > On Wed, Apr 20, 2011 at 11:59 AM, TAO HU <tghk48@xxxxxxxxxxxx> wrote: >> Hi, All >> >> I got a issue that kmalloc() fails to allocate 32-K page while there >> are still pretty much total memory available (60+MB). >> Any suggestions? Any thing I can tune to reduced the failure cases? >> >> It happens with 2.6.35 kernel >> >> <4>[ 6232.631622] getevent invoked oom-killer: gfp_mask=0xd0, order=3, oom_adj=0 >> <4>[ 6232.639312] [<c0053230>] (unwind_backtrace+0x0/0xf0) from >> [<c0109a88>] (dump_header.clone.1+0x50/0x84) >> <4>[ 6232.649597] [<c0109a88>] (dump_header.clone.1+0x50/0x84) from >> [<c0109af0>] (oom_kill_process.clone.0+0x34/0xec) >> <4>[ 6232.660705] [<c0109af0>] (oom_kill_process.clone.0+0x34/0xec) >> from [<c0109d04>] (__out_of_memory+0x15c/0x184) >> <4>[ 6232.671630] [<c0109d04>] (__out_of_memory+0x15c/0x184) from >> [<c0109dc0>] (out_of_memory+0x94/0xd4) >> <4>[ 6232.681488] [<c0109dc0>] (out_of_memory+0x94/0xd4) from >> [<c010d474>] (__alloc_pages_nodemask+0x4c4/0x6e8) >> <4>[ 6232.692016] [<c010d474>] (__alloc_pages_nodemask+0x4c4/0x6e8) >> from [<c0131fec>] (cache_grow.clone.0+0xac/0x3e4) >> <4>[ 6232.703125] [<c0131fec>] (cache_grow.clone.0+0xac/0x3e4) from >> [<c013334c>] (__kmalloc+0x3ec/0x6c4) >> <4>[ 6232.712982] [<c013334c>] (__kmalloc+0x3ec/0x6c4) from >> [<c0393f9c>] (evdev_open+0x94/0x1ec) >> <4>[ 6232.722137] [<c0393f9c>] (evdev_open+0x94/0x1ec) from >> [<c0390cac>] (input_open_file+0x184/0x2d8) >> <4>[ 6232.731781] [<c0390cac>] (input_open_file+0x184/0x2d8) from >> [<c013b668>] (chrdev_open+0x20c/0x234) >> <4>[ 6232.741638] [<c013b668>] (chrdev_open+0x20c/0x234) from >> [<c0136b80>] (__dentry_open+0x200/0x324) >> <4>[ 6232.751281] [<c0136b80>] (__dentry_open+0x200/0x324) from >> [<c0136d60>] (nameidata_to_filp+0x3c/0x50) >> <4>[ 6232.761322] [<c0136d60>] (nameidata_to_filp+0x3c/0x50) from >> [<c0142878>] (do_last+0x4c8/0x5ec) >> <4>[ 6232.770782] [<c0142878>] (do_last+0x4c8/0x5ec) from [<c0144450>] >> (do_filp_open+0x184/0x514) >> <4>[ 6232.779937] [<c0144450>] (do_filp_open+0x184/0x514) from >> [<c0136824>] (do_sys_open+0x58/0x18c) >> <4>[ 6232.789428] [<c0136824>] (do_sys_open+0x58/0x18c) from >> [<c004db20>] (ret_fast_syscall+0x0/0x30) >> <4>[ 6232.798980] Mem-info: >> <4>[ 6232.801483] Normal per-cpu: >> <4>[ 6232.804565] CPU 0: hi: 186, btch: 31 usd: 15 >> <4>[ 6232.809844] active_anon:34424 inactive_anon:36745 isolated_anon:3 >> <4>[ 6232.809875] active_file:2 inactive_file:0 isolated_file:65 >> <4>[ 6232.809875] unevictable:95 dirty:0 writeback:0 unstable:0 >> <4>[ 6232.809906] free:16133 slab_reclaimable:1274 slab_unreclaimable:3892 >> <4>[ 6232.809906] mapped:8809 shmem:263 pagetables:4657 bounce:0 >> <4>[ 6232.841766] Normal free:64532kB min:2884kB low:3604kB >> high:4324kB active_anon:137696kB inactive_anon:146980kB >> active_file:8kB inactive_file:0kB unevictable:380kB > > There are lots of anon pages but few file pages. > >> isolated(anon):12kB isolated(file):260kB present:520192kB mlocked:0kB >> dirty:0kB writeback:0kB mapped:35236kB shmem:1052kB >> slab_reclaimable:5096kB slab_unreclaimable:15568kB kernel_stack:6544kB >> pagetables:18628kB unstable:0kB bounce:0kB writeback_tmp:0kB >> pages_scanned:34 all_unreclaimable? no >> <4>[ 6232.885314] lowmem_reserve[]: 0 0 0 >> <4>[ 6232.889190] Normal: 10659*4kB 2735*8kB 1*16kB 0*32kB 0*64kB >> 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 64532kB > > There isn't any pages of bigger 32K in your system. > Memory fragmentation is high. > >> <4>[ 6232.901367] 397 total pagecache pages >> <4>[ 6232.905395] 0 pages in swap cache >> <4>[ 6232.909027] Swap cache stats: add 0, delete 0, find 0/0 >> <4>[ 6232.914764] Free swap = 0kB >> <4>[ 6232.917968] Total swap = 0kB > > You don't have swap so VM can't reclaim anon pages to get a contiguous page. > >> <4>[ 6232.945617] 131072 pages of RAM >> <4>[ 6232.949127] 17229 free pages >> <4>[ 6232.952270] 22953 reserved pages >> <4>[ 6232.955810] 5166 slab pages >> <4>[ 6232.958892] 123153 pages shared >> <4>[ 6232.962341] 0 pages swap cached >> > > It means your system has 512M but 68M is reserved. > So you can use just 444M but anon is 278M. As I said, you can't > reclaim anon paes. > There is 67M free page but you can't use it as it's small pages but > you want big page. > slab : 20M page table : 18M kernel stack : 6M. > So 278 + 67 + 20 + 18 + 6 = 389M. > 512M - 68M = 444. > Where is (444 - 389)? > I guess 55M is used by device driver and kernel. It's not accountable > in current kernel. > > Solution > 1. use CONFIG_COMPACTION=y if you don't use. > 2: consume small memory by application or device driver > 3: use swap for reclaimaing anon pages > 4 : buy bigger memory > > >> -- >> Best Regards >> Hu Tao >> >> -- >> 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> >> > > > > -- > Kind regards, > Minchan Kim > -- Best Regards Hu Tao -- 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