Re: [PATCH 4/4] mtd: nand: nandsim: convert to memalloc_noreclaim_*()

Vlastimil Babka
2017-04-05T11:39:16Z

On 04/05/2017 01:36 PM, Richard Weinberger wrote:
> Michal,
>
> Am 05.04.2017 um 13:31 schrieb Michal Hocko:
>> On Wed 05-04-17 09:47:00, Vlastimil Babka wrote:
>>> Nandsim has own functions set_memalloc() and clear_memalloc() for robust
>>> setting and clearing of PF_MEMALLOC. Replace them by the new generic helpers.
>>> No functional change.
>>
>> This one smells like an abuser. Why the hell should read/write path
>> touch memory reserves at all!
>
> Could be. Let's ask Adrian, AFAIK he wrote that code.
> Adrian, can you please clarify why nandsim needs to play with PF_MEMALLOC?

I was thinking about it and concluded that since the simulator can be
used as a block device where reclaimed pages go to, writing the data out
is a memalloc operation. Then reading can be called as part of r-m-w
cycle, so reading as well. But it would be great if somebody more
knowledgeable confirmed this.

> Thanks,
> //richard