Re: specjbb2005 fails with 2.6.29-rc4

From: Zhang, Yanmin
Date: Wed Feb 11 2009 - 20:28:41 EST


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@xxxxxxxxxxxxxxxxxxxx>
> > 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@xxxxxxxxxxxxxxxxxxxx>
> > ---
> > 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(-)
> >
>

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