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Re: [PATCH 01/18] mm: Make mmap_sem for write waits killable for mm syscalls

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On Thu 10-03-16 16:47:16, Vlastimil Babka wrote:
> On 02/29/2016 02:26 PM, Michal Hocko wrote:
> >From: Michal Hocko <mhocko@suse.com>
> >
> >This is the first step in making mmap_sem write holders killable. It
> 
> s/holders/waiters/?

right. Fixed
 
> >focuses on the trivial ones which are taking the lock early after
> >entering the syscall and they are not changing state before.
> >
> >Therefore it is very easy to change them to use down_write_killable
> >and immediately return with -EINTR. This will allow the waiter to
> >pass away without blocking the mmap_sem which might be required to
> >make a forward progress. E.g. the oom reaper will need the lock for
> >reading to dismantle the OOM victim address space.
> >
> >The only tricky function in this patch is vm_mmap_pgoff which has many
> >call sites via vm_mmap. To reduce the risk keep vm_mmap with the
> >original non-killable semantic for now.
> >
> >vm_munmap callers do not bother checking the return value so open code
> >it into the munmap syscall path for now for simplicity.
> >
> >Cc: Mel Gorman <mgorman@suse.de>
> >Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> >Cc: Konstantin Khlebnikov <koct9i@gmail.com>
> >Cc: Hugh Dickins <hughd@google.com>
> >Cc: Andrea Arcangeli <aarcange@redhat.com>
> >Cc: David Rientjes <rientjes@google.com>
> >Cc: Dave Hansen <dave.hansen@linux.intel.com>
> >Cc: Johannes Weiner <hannes@cmpxchg.org>
> >Signed-off-by: Michal Hocko <mhocko@suse.com>
> 
> Acked-by: Vlastimil Babka <vbabka@suse.cz>

Thanks!
-- 
Michal Hocko
SUSE Labs

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Re: [PATCH 01/18] mm: Make mmap_sem for write waits killable for mm  syscalls Vlastimil Babka <vbabka@suse.cz> - 2016-03-10 16:50 +0100
  Re: [PATCH 01/18] mm: Make mmap_sem for write waits killable for mm  syscalls Michal Hocko <mhocko@kernel.org> - 2016-03-10 17:00 +0100

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