Re: [PATCH V3 4/5] mm: mmap: Add mmap flag to request VM_LOCKONFAULT

[Paul Gortmaker <paul.gortmaker@windriver.com>]

On Tue, Jul 7, 2015 at 1:03 PM, Eric B Munson <emunson@akamai.com> wrote:
> The cost of faulting in all memory to be locked can be very high when
> working with large mappings.  If only portions of the mapping will be
> used this can incur a high penalty for locking.
>
> Now that we have the new VMA flag for the locked but not present state,
> expose it  as an mmap option like MAP_LOCKED -> VM_LOCKED.

An automatic bisection on arch/tile leads to this commit:

5a5656f2c9b61c74c15f9ef3fa2e6513b6c237bb is the first bad commit
commit 5a5656f2c9b61c74c15f9ef3fa2e6513b6c237bb
Author: Eric B Munson <emunson@akamai.com>
Date:   Thu Jul 16 10:09:22 2015 +1000

    mm: mmap: add mmap flag to request VM_LOCKONFAULT

Fails with:

In file included from arch/tile/mm/init.c:24:
include/linux/mman.h: In function ‘calc_vm_flag_bits’:
include/linux/mman.h:90: error: ‘MAP_LOCKONFAULT’ undeclared (first
use in this function)
include/linux/mman.h:90: error: (Each undeclared identifier is
reported only once
include/linux/mman.h:90: error: for each function it appears in.)
In file included from arch/tile/mm/mmap.c:21:
include/linux/mman.h: In function ‘calc_vm_flag_bits’:
include/linux/mman.h:90: error: ‘MAP_LOCKONFAULT’ undeclared (first
use in this function)
include/linux/mman.h:90: error: (Each undeclared identifier is
reported only once
include/linux/mman.h:90: error: for each function it appears in.)
In file included from arch/tile/mm/fault.c:24:
include/linux/mman.h: In function ‘calc_vm_flag_bits’:
include/linux/mman.h:90: error: ‘MAP_LOCKONFAULT’ undeclared (first
use in this function)
include/linux/mman.h:90: error: (Each undeclared identifier is
reported only once
include/linux/mman.h:90: error: for each function it appears in.)
In file included from arch/tile/mm/hugetlbpage.c:27:
include/linux/mman.h: In function ‘calc_vm_flag_bits’:
include/linux/mman.h:90: error: ‘MAP_LOCKONFAULT’ undeclared (first
use in this function)
include/linux/mman.h:90: error: (Each undeclared identifier is
reported only once
include/linux/mman.h:90: error: for each function it appears in.)
make[1]: *** [arch/tile/mm/hugetlbpage.o] Error 1

http://kisskb.ellerman.id.au/kisskb/buildresult/12465365/

Paul.
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