lkml.org 
[lkml]   [2012]   [Jun]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 08/20] mm: Optimize fullmm TLB flushing
From
Date
On Thu, 2012-06-28 at 01:02 +0200, Peter Zijlstra wrote:
> On Wed, 2012-06-27 at 15:26 -0700, Linus Torvalds wrote:
> > On Wed, Jun 27, 2012 at 2:15 PM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> > > This originated from s390 which does something similar and would allow
> > > s390 to use the generic TLB flushing code.
> > >
> > > The idea is to flush the mm wide cache and tlb a priory and not bother
> > > with multiple flushes if the batching isn't large enough.
> > >
> > > This can be safely done since there cannot be any concurrency on this
> > > mm, its either after the process died (exit) or in the middle of
> > > execve where the thread switched to the new mm.
> >
> > I think we actually *used* to do the final TLB flush from within the
> > context of the process that died. That doesn't seem to ever be the
> > case any more, but it does worry me a bit. Maybe a
> >
> > VM_BUG_ON(current->active_mm == mm);
> >
> > or something for the fullmm case?
>
> OK, added it and am rebooting the test box..

That triggered.. is this a problem though, at this point userspace is
very dead so it shouldn't matter, right?

Will have to properly think about it tomorrow, its been 1am, brain is
mostly sleeping already.

------------[ cut here ]------------
kernel BUG at /home/root/src/linux-2.6/mm/memory.c:221!
invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
Modules linked in:
CPU 13
Pid: 132, comm: modprobe Not tainted 3.5.0-rc4-01507-g912ca15-dirty #180 Supermicro X8DTN/X8DTN
RIP: 0010:[<ffffffff811511bf>] [<ffffffff811511bf>] tlb_gather_mmu+0x9f/0xb0
RSP: 0018:ffff880235b2bd78 EFLAGS: 00010246
RAX: ffff880235b18000 RBX: ffff880235b2bdc0 RCX: ffff880235b18000
RDX: 0000000000000000 RSI: 0000000000000100 RDI: 0000000000000000
RBP: ffff880235b2bd98 R08: 0000000000000018 R09: 0000000000000004
R10: ffffffff81eedfc0 R11: 0000000000000084 R12: ffff8804356b8000
R13: 0000000000000001 R14: ffff880235b185f0 R15: ffff880235b18000
FS: 0000000000000000(0000) GS:ffff880237ce0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000038ce8ae150 CR3: 0000000436ad6000 CR4: 00000000000007e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process modprobe (pid: 132, threadinfo ffff880235b2a000, task ffff880235b18000)
Stack:
ffff880235b2bd98 0000000000000000 ffff8804356b8000 ffff8804356b8060
ffff880235b2be38 ffffffff8115ad38 ffff880235b2be38 ffff880235b4e000
ffff880235b4e630 ffff8804356b8000 0000000100000000 ffff880235b2bdd8
Call Trace:
[<ffffffff8115ad38>] exit_mmap+0x98/0x150
[<ffffffff810bf98e>] ? exit_numa+0xae/0xe0
[<ffffffff81078b74>] mmput+0x84/0x120
[<ffffffff81080ce8>] exit_mm+0x108/0x130
[<ffffffff81081388>] do_exit+0x678/0x950
[<ffffffff811a3ad6>] ? alloc_fd+0xd6/0x120
[<ffffffff811791c0>] ? kmem_cache_free+0x20/0x130
[<ffffffff810819af>] do_group_exit+0x3f/0xa0
[<ffffffff81081a27>] sys_exit_group+0x17/0x20
[<ffffffff81980ed2>] system_call_fastpath+0x16/0x1b
Code: 10 74 1a 65 48 8b 04 25 80 ba 00 00 4c 3b a0 90 02 00 00 74 16 4c 89 e7 e8 5f 39 f2 ff 48 8b 5d e8 4c 8b 65 f0 4c 8b 6d f8 c9 c3 <0f> 0b 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5
RIP [<ffffffff811511bf>] tlb_gather_mmu+0x9f/0xb0
RSP <ffff880235b2bd78>
---[ end trace f99f121b09c974f8 ]---



\
 
 \ /
  Last update: 2012-06-28 02:01    [W:2.975 / U:0.004 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site