Re: [PATCH 2/2] core.fsyncobjectfiles: batch disk flushes

On Wed, Aug 25, 2021 at 10:40:53AM -0700, Neeraj Singh wrote:

I'd expect syncfs to suffer from the noisy-neighbor problem that Linus
alluded to on the big
thread you kicked off.

It does.  That being said I suspect in most developer workstation
use cases it will still be a win.  Maybe I'll look into implemeting
it after your series lands.

If someone adds a more targeted bulk sync interface to the Linux
kernel, I'm sure Git could be
changed to use it. Maybe an fcntl(2) interface that initiates
writeback and registers completion with an
eventfd.

That is in general very hard to do with how the VM-level writeback
occurs.  In the file system itself it could work much better, e.g.
for XFS we write the log up to a specific sequence number and could
notify when doing that.