Re: [PATCH] f2fs: limit # of inmemory pages

[Christoph Hellwig]

On Wed, Oct 18, 2017 at 07:15:16PM -0700, Jaegeuk Kim wrote:
> If some abnormal users try lots of atomic write operations, f2fs is able to
> produce pinned pages in the main memory which affects system performance.
> This patch limits that as 20% over total memory size, and if f2fs reaches
> to the limit, it will drop all the inmemory pages.

Can you please document your "atomic" writes and how they pin memory
in a mail to linux-abi?  And how they compare to my O_ATOMIC implement
as well as the papers it is based on?

I tried to take a quick look at the code and it looks very bogus to me
in addition to being sneaked in through fs-specific ioctls without any
review whatsoever.