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Message-ID: <84144f020908310308i48790f78g5a7d73a60ea854f8@mail.gmail.com> Date: Mon, 31 Aug 2009 13:08:19 +0300 From: Pekka Enberg <penberg@...helsinki.fi> To: Paul Mundt <lethal@...ux-sh.org>, Mel Gorman <mel@....ul.ie>, Christoph Lameter <cl@...ux-foundation.org>, KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>, Pekka Enberg <penberg@...helsinki.fi>, Peter Zijlstra <a.p.zijlstra@...llo.nl>, Nick Piggin <nickpiggin@...oo.com.au>, Dave Hansen <dave@...ux.vnet.ibm.com>, Lee Schermerhorn <Lee.Schermerhorn@...com>, Andrew Morton <akpm@...ux-foundation.org>, Linus Torvalds <torvalds@...ux-foundation.org>, David Howells <dhowells@...hat.com>, linux-mm@...ck.org, linux-kernel@...r.kernel.org Subject: Re: page allocator regression on nommu Hi Paul, On Mon, Aug 31, 2009 at 10:48 AM, Paul Mundt<lethal@...ux-sh.org> wrote: > It seems we've managed to trigger a fairly interesting conflict between > the anti-fragmentation disabling code and the nommu region rbtree. I've > bisected it down to: > > commit 49255c619fbd482d704289b5eb2795f8e3b7ff2e > Author: Mel Gorman <mel@....ul.ie> > Date: Tue Jun 16 15:31:58 2009 -0700 > > page allocator: move check for disabled anti-fragmentation out of fastpath > > On low-memory systems, anti-fragmentation gets disabled as there is > nothing it can do and it would just incur overhead shuffling pages between > lists constantly. Currently the check is made in the free page fast path > for every page. This patch moves it to a slow path. On machines with low > memory, there will be small amount of additional overhead as pages get > shuffled between lists but it should quickly settle. > > which causes death on unpacking initramfs on my nommu board. With this > reverted, everything works as expected. Note that this blows up with all of > SLOB/SLUB/SLAB. > > I'll continue debugging it, and can post my .config if it will be helpful, but > hopefully you have some suggestions on what to try :-) > > --- > > modprobe: page allocation failure. order:7, mode:0xd0 OK, so we have order 7 page allocation here... > Stack: (0x0c909d2c to 0x0c90a000) > 9d20: 0c0387d2 00000000 00000000 0c107fcc 00000000 > 9d40: 00000000 0c107fcc 0c2f8960 00000000 00000010 00000000 00000000 000200d0 > 9d60: 00000000 0c041614 0c9f8cf4 00000000 0c9f8d1c 00000000 00000004 00000000 > 9d80: 00000007 0c01a582 0c2f8cd0 00000000 00000000 00049000 00000049 00048fff > 9da0: 00049fff 00049000 00000007 0c06633a 00000001 0c909f30 0003e950 0c0bad00 > 9dc0: 0000984a 0c2f8ea0 ffffe000 00000002 00000000 0c065314 0c2f8ea0 0c077f60 > 9de0: 00049000 0000673c 00000050 000369a0 000019cf 00000004 00004e20 0003e950 > 9e00: 000481aa 00000001 00004eaa 000049a0 00007fb0 000369a0 00000000 00000000 > 9e20: 0c909e50 00000000 00000000 0c066790 00000000 0c909f30 00000000 00000000 > 9e40: 0c2f8ea0 0c909f30 0c909e50 00004eaa 00000000 00000000 00000000 00000000 > 9e60: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > 9e80: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > 9ea0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > 9ec0: 0c0482ee 00000000 fffffff8 0c2f8ea0 0c104ff8 0c04884e 0c0feb64 00000001 > 9ee0: 0c048570 ffffe000 0c2f8ea0 00000000 00000000 0c813eb8 0c909f30 0c002e68 > 9f00: 00000000 00000000 00000000 0c0feb64 0c813eb8 0c909f30 0c960000 0c007972 > 9f20: ffffff0f 00000071 00000100 0c002e38 0000000b ffffff0f 00000001 0000000b > 9f40: 0c0fea64 0c813eb8 0c0feb64 0c2f898c 00000000 ffffe000 0c9f8990 00000000 > 9f60: 00000000 00000000 00000000 0c909f8c 0c0050ca 0c01e874 40000001 00000000 > 9f80: 00000000 4795ce40 0000004c 0c002cca 00000000 00000000 00000000 00000000 > 9fa0: 00000000 00000000 00000000 00000000 00000000 0c9f8990 0c01e7a4 00000000 > 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > 9fe0: 0c909f9c 0c002cc4 00000000 40000000 00000000 00000000 00000000 00000000 > > Call trace: > [<0c041614>] do_mmap_pgoff+0x638/0xa68 > [<0c01a582>] flush_itimer_signals+0x36/0x60 > [<0c06633a>] load_flat_file+0x32a/0x738 > [<0c0bad00>] down_write+0x0/0xc > [<0c065314>] load_elf_fdpic_binary+0x44/0xa8c > [<0c077f60>] memset+0x0/0x60 > [<0c066790>] load_flat_binary+0x48/0x2fc > [<0c0482ee>] search_binary_handler+0x4a/0x1fc > [<0c04884e>] do_execve+0x156/0x2bc > [<0c048570>] copy_strings+0x0/0x150 > [<0c002e68>] sys_execve+0x30/0x5c > [<0c007972>] syscall_call+0xc/0x10 > [<0c002e38>] sys_execve+0x0/0x5c > [<0c0050ca>] kernel_execve+0x6/0xc > [<0c01e874>] ____call_usermodehelper+0xd0/0xfc > [<0c002cca>] kernel_thread_helper+0x6/0x10 > [<0c01e7a4>] ____call_usermodehelper+0x0/0xfc > [<0c002cc4>] kernel_thread_helper+0x0/0x10 > > Mem-Info: > Normal per-cpu: > CPU 0: hi: 0, btch: 1 usd: 0 > Active_anon:0 active_file:0 inactive_anon:0 > inactive_file:0 unevictable:323 dirty:0 writeback:0 unstable:0 > free:2967 slab:0 mapped:0 pagetables:0 bounce:0 > Normal free:11868kB min:0kB low:0kB high:0kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:1292kB present:16256kB pages_scanned:0 all_unreclaimable? no > lowmem_reserve[]: 0 0 > Normal: 267*4kB 268*8kB 251*16kB 145*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB 0*8192kB 0*16384kB 0*32768kB = 11868kB ...but we seem to be all out of order > 3 pages. I'm not sure why commit 49255c619fbd482d704289b5eb2795f8e3b7ff2e changes any of this, though. > 323 total pagecache pages > ------------[ cut here ]------------ > kernel BUG at mm/nommu.c:598! > Kernel BUG: 003e [#1] > Modules linked in: > > Pid : 51, Comm: modprobe > CPU : 0 Not tainted (2.6.31-rc7 #2835) > > PC is at __put_nommu_region+0xe/0xb0 > PR is at do_mmap_pgoff+0x8dc/0xa68 This looks to be a bug in nommu do_mmap_pgoff() error handling. I guess we shouldn't call __put_nommu_region() if add_nommu_region() hasn't been called? > PC : 0c040e7a SP : 0c909d7c SR : 40000001 > R0 : 0000001d R1 : 00000000 R2 : 00000000 R3 : 0000000d > R4 : 0c9f8cf4 R5 : 000017de R6 : ffffffff R7 : 00000035 > R8 : 0c9f8cf4 R9 : 00000000 R10 : 00000000 R11 : fffffff4 > R12 : 0c9f8d1c R13 : 00000000 R14 : 0c9f8cf4 > MACH: 0000017e MACL: baf11680 GBR : 00000000 PR : 0c0418b8 > > Call trace: > [<0c0418b8>] do_mmap_pgoff+0x8dc/0xa68 > [<0c01a582>] flush_itimer_signals+0x36/0x60 > [<0c06633a>] load_flat_file+0x32a/0x738 > [<0c0bad00>] down_write+0x0/0xc > [<0c065314>] load_elf_fdpic_binary+0x44/0xa8c > [<0c077f60>] memset+0x0/0x60 > [<0c066790>] load_flat_binary+0x48/0x2fc > [<0c0482ee>] search_binary_handler+0x4a/0x1fc > [<0c04884e>] do_execve+0x156/0x2bc > [<0c048570>] copy_strings+0x0/0x150 > [<0c002e68>] sys_execve+0x30/0x5c > [<0c007972>] syscall_call+0xc/0x10 > [<0c002e38>] sys_execve+0x0/0x5c > [<0c0050ca>] kernel_execve+0x6/0xc > [<0c01e874>] ____call_usermodehelper+0xd0/0xfc > [<0c002cca>] kernel_thread_helper+0x6/0x10 > [<0c01e7a4>] ____call_usermodehelper+0x0/0xfc > [<0c002cc4>] kernel_thread_helper+0x0/0x10 > > Code: > 0c040e74: tst r1, r1 > 0c040e76: bf.s 0c040e7c > 0c040e78: mov r4, r8 > ->0c040e7a: trapa #62 > 0c040e7c: stc sr, r1 > 0c040e7e: mov r1, r0 > 0c040e80: or #-16, r0 > 0c040e82: ldc r0, sr > 0c040e84: mov r1, r0 > > Process: modprobe (pid: 51, stack limit = 0c908001) > Stack: (0x0c909d7c to 0x0c90a000) > 9d60: 0c0418b8 > 9d80: 00000007 0c01a582 0c2f8cd0 00000000 00000000 00049000 00000049 00048fff > 9da0: 00049fff 00049000 00000007 0c06633a 00000001 0c909f30 0003e950 0c0bad00 > 9dc0: 0000984a 0c2f8ea0 ffffe000 00000002 00000000 0c065314 0c2f8ea0 0c077f60 > 9de0: 00049000 0000673c 00000050 000369a0 000019cf 00000004 00004e20 0003e950 > 9e00: 000481aa 00000001 00004eaa 000049a0 00007fb0 000369a0 00000000 00000000 > 9e20: 0c909e50 00000000 00000000 0c066790 00000000 0c909f30 00000000 00000000 > 9e40: 0c2f8ea0 0c909f30 0c909e50 00004eaa 00000000 00000000 00000000 00000000 > 9e60: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > 9e80: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > 9ea0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > 9ec0: 0c0482ee 00000000 fffffff8 0c2f8ea0 0c104ff8 0c04884e 0c0feb64 00000001 > 9ee0: 0c048570 ffffe000 0c2f8ea0 00000000 00000000 0c813eb8 0c909f30 0c002e68 > 9f00: 00000000 00000000 00000000 0c0feb64 0c813eb8 0c909f30 0c960000 0c007972 > 9f20: ffffff0f 00000071 00000100 0c002e38 0000000b ffffff0f 00000001 0000000b > 9f40: 0c0fea64 0c813eb8 0c0feb64 0c2f898c 00000000 ffffe000 0c9f8990 00000000 > 9f60: 00000000 00000000 00000000 0c909f8c 0c0050ca 0c01e874 40000001 00000000 > 9f80: 00000000 4795ce40 0000004c 0c002cca 00000000 00000000 00000000 00000000 > 9fa0: 00000000 00000000 00000000 00000000 00000000 0c9f8990 0c01e7a4 00000000 > 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > 9fe0: 0c909f9c 0c002cc4 00000000 40000000 00000000 00000000 00000000 00000000 > ---[ end trace 139ce121c98e96c9 ]--- > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@...ck.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@...ck.org"> email@...ck.org </a> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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