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    Stop playing silly games with the VM_ACCOUNT flag · fc8744ad
    Linus Torvalds 提交于
    The mmap_region() code would temporarily set the VM_ACCOUNT flag for
    anonymous shared mappings just to inform shmem_zero_setup() that it
    should enable accounting for the resulting shm object.  It would then
    clear the flag after calling ->mmap (for the /dev/zero case) or doing
    shmem_zero_setup() (for the MAP_ANON case).
    
    This just resulted in vma merge issues, but also made for just
    unnecessary confusion.  Use the already-existing VM_NORESERVE flag for
    this instead, and let shmem_{zero|file}_setup() just figure it out from
    that.
    
    This also happens to make it obvious that the new DRI2 GEM layer uses a
    non-reserving backing store for its object allocation - which is quite
    possibly not intentional.  But since I didn't want to change semantics
    in this patch, I left it alone, and just updated the caller to use the
    new flag semantics.
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    fc8744ad
mmap.c 64.1 KB