Messages in this thread | | | Date | Wed, 16 Dec 2009 11:11:07 +0100 | From | Andi Kleen <> | Subject | Re: [mm][RFC][PATCH 0/11] mm accessor updates. |
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On Wed, Dec 16, 2009 at 12:00:11PM +0900, KAMEZAWA Hiroyuki wrote: > This is from Christoph Lameter's mm_accessor patch posted 5/Nov. > > Replacing all access to mm->mmap_sem with mm-accessor functions as > mm_read_lock, > mm_write_lock, > etc... > > This kind of function allows us to improve page fault performance etc.. > For example, skil down_read(mmap_sem) in some situation. > (as: http://marc.info/?l=linux-mm&m=125809791306459&w=2)
The problem is that it also slows down the writers, and we have some workloads where writing is the bottleneck.
I don't think this is the right trade off at this time.
Also the patches didn't fare too well in testing unfortunately.
I suspect we'll rather need multiple locks split per address space range.
-Andi
-- ak@linux.intel.com -- Speaking for myself only.
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