Re: [RFC 0/6] zsmalloc support compaction

["\"박승호/책임연구원/SW Platform(연)AOT팀(seungho1.park@lge.com)\"" <seungho1.park@lge.com>]

Hi, Minchan.

Sorry, I got it. You made zsmalloc pages movable.
forget it.

Seungho.

2014-12-04 i??i?? 3:49i?? "e??i?1i?,/i+-?i??i??eu!i??/SW Platform(i??)AOTi?? 
(seungho1.park@lge.com)" i?'(e??) i?' e,?:
> Hi, Minchan.
>
> I have a question.
> The problem mentioned can't be resolved with compaction?
> Is there any reason that zsmalloc pages can't be moved by compaction
> operation in direct reclaim?
>
> 2014-12-02 i??i ? 11:49i?? Minchan Kim i?'(e??) i?' e,?:
>> Recently, there was issue about zsmalloc fragmentation and
>> I got a report from Juno that new fork failed although there
>> are plenty of free pages in the system.
>> His investigation revealed zram is one of the culprit to make
>> heavy fragmentation so there was no more contiguous 16K page
>> for pgd to fork in the ARM.
>>
>> This patchset implement *basic* zsmalloc compaction support
>> and zram utilizes it so admin can do
>>     "echo 1 > /sys/block/zram0/compact"
>>
>> Actually, ideal is that mm migrate code is aware of zram pages and
>> migrate them out automatically without admin's manual opeartion
>> when system is out of contiguous page. Howver, we need more thinking
>> before adding more hooks to migrate.c. Even though we implement it,
>> we need manual trigger mode, too so I hope we could enhance
>> zram migration stuff based on this primitive functions in future.
>>
>> I just tested it on only x86 so need more testing on other arches.
>> Additionally, I should have a number for zsmalloc regression
>> caused by indirect layering. Unfortunately, I don't have any
>> ARM test machine on my desk. I will get it soon and test it.
>> Anyway, before further work, I'd like to hear opinion.
>>
>> Pathset is based on v3.18-rc6-mmotm-2014-11-26-15-45.
>>
>> Thanks.
>>
>> Minchan Kim (6):
>>    zsmalloc: expand size class to support sizeof(unsigned long)
>>    zsmalloc: add indrection layer to decouple handle from object
>>    zsmalloc: implement reverse mapping
>>    zsmalloc: encode alloced mark in handle object
>>    zsmalloc: support compaction
>>    zram: support compaction
>>
>>   drivers/block/zram/zram_drv.c |  24 ++
>>   drivers/block/zram/zram_drv.h |   1 +
>>   include/linux/zsmalloc.h      |   1 +
>>   mm/zsmalloc.c                 | 596 
>> +++++++++++++++++++++++++++++++++++++-----
>>   4 files changed, 552 insertions(+), 70 deletions(-)
>>
>

--
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>