Re: [patch] x86: Fix incorrect __read_mostly on _boot_cpu_pda

From: Ingo Molnar
Date: Fri Jan 02 2009 - 14:21:24 EST



* Ravikiran G Thirumalai <kiran@xxxxxxxxxxxx> wrote:

> On Fri, Jan 02, 2009 at 05:09:51PM +0100, Ingo Molnar wrote:
> >
> >* Ravikiran G Thirumalai <kiran@xxxxxxxxxxxx> wrote:
> >
> >> The pda rework (commit 3461b0af025251bbc6b3d56c821c6ac2de6f7209)
> >> to remove static boot cpu pdas introduced a bug. _boot_cpu_pda is the
> >> actual pda used by the boot cpu and is definitely not "__read_mostly" and
> >> ended up polluting the read mostly section with writes. This bug caused
> >> regression of about 8-10% on certain syscall intensive workloads.
> >>
> >> Signed-off-by: Ravikiran Thirumalai <kiran@xxxxxxxxxxxx>
> >
> >applied to tip/x86/urgent, with a Cc: stable tag. Thanks,
> >
>
> Thanks!
>
> Stable maintainers, please consider this for 2.6.27 stable as well (in
> addition to 28). (Attaching the tip/x86/urgent commit as reference to
> the patch)

i have added a -stable tag to the commit - please only put it into -stable
once it hits Linus's tree. (in the next couple of days)

>
Ingo
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