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

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

[Paul Gortmaker]

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.
--

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

[Chris Metcalf]

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

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

-- 
Chris Metcalf, EZChip Semiconductor
http://www.ezchip.com

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

[Eric B Munson]

[-- Attachment #1: Type: text/plain, Size: 1051 bytes --]

On Mon, 20 Jul 2015, Chris Metcalf wrote:

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

Eric

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

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

[Paul Gortmaker]

On 2015-07-21 11:37 AM, Eric B Munson wrote:
> On Mon, 20 Jul 2015, Chris Metcalf wrote:
> 
>> On 07/18/2015 03:11 PM, Paul Gortmaker wrote:
>>> 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
>>
>> 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
> 

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>