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

On 2015-07-21 11:37 AM, Eric B Munson wrote:

On Mon, 20 Jul 2015, Chris Metcalf wrote:

quoted

On 07/18/2015 03:11 PM, Paul Gortmaker wrote:

quoted

On Tue, Jul 7, 2015 at 1:03 PM, Eric B Munson[off-list ref]  wrote:

quoted

quoted

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[off-list ref]
Date:   Thu Jul 16 10:09:22 2015 +1000

    mm: mmap: add mmap flag to request VM_LOCKONFAULT

Eric, I'm happy to help with figuring out the tile issues.

Thanks for the offer, I think I have is sorted in V4 (which I am
checking one last time before I post).

Not quite sorted yet.  Seems parisc fails on v4.  It updated the
number of syscalls but did not update syscall_table.S causing:

arch/parisc/kernel/syscall_table.S:444: Error: size of syscall table does not fit value of __NR_Linux_syscalls

http://kisskb.ellerman.id.au/kisskb/buildresult/12468884/

Paul.
--

Eric

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