* specjbb2005 fails with 2.6.29-rc4
@ 2009-02-12 1:16 Lin Ming
2009-02-12 1:20 ` Lin Ming
2009-02-12 1:35 ` Linus Torvalds
0 siblings, 2 replies; 5+ messages in thread
From: Lin Ming @ 2009-02-12 1:16 UTC (permalink / raw)
To: torvalds; +Cc: linux-kernel, Zhang, Yanmin
specjbb2005 fails with 2.6.29-rc4 in many testing machines.
On a 4*4cores Tigerton machine, run specjb2005 with
starting_number_warehouses = 1 and ending_number_warehouses = 34.
It fails when warehouses=16.
Test with Jrockit VM fails. And it works well if OpenJDK is used
instead.
commit fc8744adc870a8d4366908221508bb113d8b72ee
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date: Sat Jan 31 15:08:56 2009 -0800
Stop playing silly games with the VM_ACCOUNT flag
The mmap_region() code would temporarily set the VM_ACCOUNT flag for
anonymous shared mappings just to inform shmem_zero_setup() that it
should enable accounting for the resulting shm object. It would then
clear the flag after calling ->mmap (for the /dev/zero case) or doing
shmem_zero_setup() (for the MAP_ANON case).
This just resulted in vma merge issues, but also made for just
unnecessary confusion. Use the already-existing VM_NORESERVE flag for
this instead, and let shmem_{zero|file}_setup() just figure it out from
that.
This also happens to make it obvious that the new DRI2 GEM layer uses a
non-reserving backing store for its object allocation - which is quite
possibly not intentional. But since I didn't want to change semantics
in this patch, I left it alone, and just updated the caller to use the
new flag semantics.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
drivers/gpu/drm/drm_gem.c | 2 +-
ipc/shm.c | 4 +-
mm/mmap.c | 48 +++++++++++++++++++++++---------------------
mm/shmem.c | 2 +-
4 files changed, 29 insertions(+), 27 deletions(-)
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: specjbb2005 fails with 2.6.29-rc4
2009-02-12 1:16 specjbb2005 fails with 2.6.29-rc4 Lin Ming
@ 2009-02-12 1:20 ` Lin Ming
2009-02-12 1:28 ` Zhang, Yanmin
2009-02-12 1:35 ` Linus Torvalds
1 sibling, 1 reply; 5+ messages in thread
From: Lin Ming @ 2009-02-12 1:20 UTC (permalink / raw)
To: torvalds; +Cc: linux-kernel, Zhang, Yanmin
On Thu, 2009-02-12 at 09:16 +0800, Lin Ming wrote:
> specjbb2005 fails with 2.6.29-rc4 in many testing machines.
>
> On a 4*4cores Tigerton machine, run specjb2005 with
> starting_number_warehouses = 1 and ending_number_warehouses = 34.
> It fails when warehouses=16.
>
> Test with Jrockit VM fails. And it works well if OpenJDK is used
> instead.
Bisect locates below commit.
>
> commit fc8744adc870a8d4366908221508bb113d8b72ee
> Author: Linus Torvalds <torvalds@linux-foundation.org>
> Date: Sat Jan 31 15:08:56 2009 -0800
>
> Stop playing silly games with the VM_ACCOUNT flag
>
> The mmap_region() code would temporarily set the VM_ACCOUNT flag for
> anonymous shared mappings just to inform shmem_zero_setup() that it
> should enable accounting for the resulting shm object. It would then
> clear the flag after calling ->mmap (for the /dev/zero case) or doing
> shmem_zero_setup() (for the MAP_ANON case).
>
> This just resulted in vma merge issues, but also made for just
> unnecessary confusion. Use the already-existing VM_NORESERVE flag for
> this instead, and let shmem_{zero|file}_setup() just figure it out from
> that.
>
> This also happens to make it obvious that the new DRI2 GEM layer uses a
> non-reserving backing store for its object allocation - which is quite
> possibly not intentional. But since I didn't want to change semantics
> in this patch, I left it alone, and just updated the caller to use the
> new flag semantics.
>
> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
> ---
> drivers/gpu/drm/drm_gem.c | 2 +-
> ipc/shm.c | 4 +-
> mm/mmap.c | 48 +++++++++++++++++++++++---------------------
> mm/shmem.c | 2 +-
> 4 files changed, 29 insertions(+), 27 deletions(-)
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: specjbb2005 fails with 2.6.29-rc4
2009-02-12 1:20 ` Lin Ming
@ 2009-02-12 1:28 ` Zhang, Yanmin
0 siblings, 0 replies; 5+ messages in thread
From: Zhang, Yanmin @ 2009-02-12 1:28 UTC (permalink / raw)
To: Lin Ming; +Cc: torvalds, linux-kernel
On Thu, 2009-02-12 at 09:20 +0800, Lin Ming wrote:
> On Thu, 2009-02-12 at 09:16 +0800, Lin Ming wrote:
> > specjbb2005 fails with 2.6.29-rc4 in many testing machines.
> >
> > On a 4*4cores Tigerton machine, run specjb2005 with
> > starting_number_warehouses = 1 and ending_number_warehouses = 34.
> > It fails when warehouses=16.
> >
> > Test with Jrockit VM fails. And it works well if OpenJDK is used
> > instead.
One difference between Jrockit and OpenJDK is Jrokit uses huge pages.
>
> Bisect locates below commit.
>
> >
> > commit fc8744adc870a8d4366908221508bb113d8b72ee
> > Author: Linus Torvalds <torvalds@linux-foundation.org>
> > Date: Sat Jan 31 15:08:56 2009 -0800
> >
> > Stop playing silly games with the VM_ACCOUNT flag
> >
> > The mmap_region() code would temporarily set the VM_ACCOUNT flag for
> > anonymous shared mappings just to inform shmem_zero_setup() that it
> > should enable accounting for the resulting shm object. It would then
> > clear the flag after calling ->mmap (for the /dev/zero case) or doing
> > shmem_zero_setup() (for the MAP_ANON case).
> >
> > This just resulted in vma merge issues, but also made for just
> > unnecessary confusion. Use the already-existing VM_NORESERVE flag for
> > this instead, and let shmem_{zero|file}_setup() just figure it out from
> > that.
> >
> > This also happens to make it obvious that the new DRI2 GEM layer uses a
> > non-reserving backing store for its object allocation - which is quite
> > possibly not intentional. But since I didn't want to change semantics
> > in this patch, I left it alone, and just updated the caller to use the
> > new flag semantics.
> >
> > Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
> > ---
> > drivers/gpu/drm/drm_gem.c | 2 +-
> > ipc/shm.c | 4 +-
> > mm/mmap.c | 48 +++++++++++++++++++++++---------------------
> > mm/shmem.c | 2 +-
> > 4 files changed, 29 insertions(+), 27 deletions(-)
> >
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: specjbb2005 fails with 2.6.29-rc4
2009-02-12 1:16 specjbb2005 fails with 2.6.29-rc4 Lin Ming
2009-02-12 1:20 ` Lin Ming
@ 2009-02-12 1:35 ` Linus Torvalds
2009-02-12 3:23 ` Lin Ming
1 sibling, 1 reply; 5+ messages in thread
From: Linus Torvalds @ 2009-02-12 1:35 UTC (permalink / raw)
To: Lin Ming; +Cc: linux-kernel, Zhang, Yanmin, Mel Gorman
On Thu, 12 Feb 2009, Lin Ming wrote:
>
> Test with Jrockit VM fails. And it works well if OpenJDK is used
> instead.
I suspect maybe it uses hugetlbs?
There were a couple of commits to fix VM_ACCOUNT for hugepage areas
recently. See
- 5a6fe125950676015f5108fb71b2a67441755003: "Do not account for the
address space used by hugetlbfs using VM_ACCOUNT"
- 17c9d12e126cb0de8d535dc1908c4819d712bc68: "Do not account for hugetlbfs
quota at mmap() time if mapping [SHM|MAP]_NORESERVE"
because hugetlb mappings have their own magical VM accounting.
So can you check if current -git fixes it?
Linus
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: specjbb2005 fails with 2.6.29-rc4
2009-02-12 1:35 ` Linus Torvalds
@ 2009-02-12 3:23 ` Lin Ming
0 siblings, 0 replies; 5+ messages in thread
From: Lin Ming @ 2009-02-12 3:23 UTC (permalink / raw)
To: Linus Torvalds; +Cc: linux-kernel, Zhang, Yanmin, Mel Gorman
On Thu, 2009-02-12 at 09:35 +0800, Linus Torvalds wrote:
>
> On Thu, 12 Feb 2009, Lin Ming wrote:
> >
> > Test with Jrockit VM fails. And it works well if OpenJDK is used
> > instead.
>
> I suspect maybe it uses hugetlbs?
>
> There were a couple of commits to fix VM_ACCOUNT for hugepage areas
> recently. See
>
> - 5a6fe125950676015f5108fb71b2a67441755003: "Do not account for the
> address space used by hugetlbfs using VM_ACCOUNT"
>
> - 17c9d12e126cb0de8d535dc1908c4819d712bc68: "Do not account for hugetlbfs
> quota at mmap() time if mapping [SHM|MAP]_NORESERVE"
>
> because hugetlb mappings have their own magical VM accounting.
>
> So can you check if current -git fixes it?
Yes, current -git fixes it.
Lin Ming
^ permalink raw reply [flat|nested] 5+ messages in thread
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2009-02-12 1:16 specjbb2005 fails with 2.6.29-rc4 Lin Ming
2009-02-12 1:20 ` Lin Ming
2009-02-12 1:28 ` Zhang, Yanmin
2009-02-12 1:35 ` Linus Torvalds
2009-02-12 3:23 ` Lin Ming
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