On Thu 10-03-16 16:47:16, Vlastimil Babka wrote: > On 02/29/2016 02:26 PM, Michal Hocko wrote: > >From: Michal Hocko <[email protected]> > > > >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 <[email protected]> > >Cc: "Kirill A. Shutemov" <[email protected]> > >Cc: Konstantin Khlebnikov <[email protected]> > >Cc: Hugh Dickins <[email protected]> > >Cc: Andrea Arcangeli <[email protected]> > >Cc: David Rientjes <[email protected]> > >Cc: Dave Hansen <[email protected]> > >Cc: Johannes Weiner <[email protected]> > >Signed-off-by: Michal Hocko <[email protected]> > > Acked-by: Vlastimil Babka <[email protected]> Thanks! -- Michal Hocko SUSE Labs
