On 29.01.25 02:25, Joanne Koong wrote:
On Tue, Jan 28, 2025 at 3:10 AM Miklos Szeredi <miklos@xxxxxxxxxx> wrote:
On Mon, 27 Jan 2025 at 22:44, Joanne Koong <joannelkoong@xxxxxxxxx> wrote:
Hi all,
Recently, there was a long discussion upstream [1] on a patchset that
removes temp pages when handling writeback in FUSE. Temp pages are the
main bottleneck for write performance in FUSE and local benchmarks
showed approximately a 20% and 45% improvement in throughput for 4K
and 1M block size writes respectively when temp pages were removed.
More information on how FUSE uses temp pages can be found here [2].
In the discussion, there were concerns from mm regarding the
possibility of untrusted malicious or buggy fuse servers never
completing writeback, which would impede migration for those pages.
It would be great to continue this discussion at LSF/MM and align on a
solution that removes FUSE temp pages altogether while satisfying mm’s
expectations for page migration. These are the most promising options
so far:
This is more than just temp pages. The same issue exists for
->readahead(). This needs to be approached from both directions.
I was assuming the cases for readahead and writethrough splice was
going to be covered in the more generic mm session about which
existing things in the system currently lead pages to be
indeterminately unmigratable and which can be handled vs not. David,
were you still planning to propose that as a topic?
Heh, deadline is February 1, so I can still propose it as a rather open
topic to gather some other cases people might be aware of and what we
can do about them.
--
Cheers,
David / dhildenb
