Re: [PATCH 00/25] mm: Preemptibility -v7

From: Sam Ravnborg
Date: Tue Jan 25 2011 - 13:32:47 EST

On Tue, Jan 25, 2011 at 06:31:11PM +0100, Peter Zijlstra wrote:
> This patch-set makes part of the mm a lot more preemptible. It converts
> i_mmap_lock and anon_vma->lock to mutexes and makes mmu_gather fully
> preemptible.
> The main motivation was making mm_take_all_locks() preemptible, since it
> appears people are nesting hundreds of spinlocks there.
> The side-effects are that can finally make mmu_gather preemptible,
> something which lots of people have wanted to do for a long time.
> It also gets us anon_vma refcounting, which seems to result in a nice
> cleanup of the anon_vma lifetime rules wrt KSM and compaction.
> This patch-set is build and boot-tested on x86_64 (a previous version was
> also tested on Dave's Niagra2 machines, and I suppose s390 was too when
> Martin provided the conversion patch for his arch).
> There are no known architectures left unconverted.

Hi Peter.

Foregive me my ignorance..
Why is this relevant for sparc64 but not for sparc32?

A quick grep showed up only this in sparc32 specific files:

mm/init_32.c:DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);

Maybe this is just something sparc32 does not support?

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