Messages in this thread | | | Subject | Re: [PATCH 01/18] mm: Make mmap_sem for write waits killable for mm syscalls | From | Vlastimil Babka <> | Date | Thu, 10 Mar 2016 16:47:16 +0100 |
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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/?
> 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>
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