Messages in this thread | | | Date | Mon, 30 Jan 2023 14:55:59 -0700 | Subject | Re: [GIT PULL] iov_iter: Improve page extraction (pin or just list) | From | Jens Axboe <> |
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On 1/30/23 2:33 PM, Jens Axboe wrote: > On 1/30/23 4:14 AM, David Howells wrote: >> Hi Jens, >> >> Could you consider pulling this patchset into the block tree? I think that >> Al's fears wrt to pinned pages being removed from page tables causing deadlock >> have been answered. Granted, there is still the issue of how to handle >> vmsplice and a bunch of other places to fix, not least skbuff handling. >> >> I also have patches to fix cifs in a separate branch that I would also like to >> push in this merge window - and that requires the first two patches from this >> series also, so would it be possible for you to merge at least those two >> rather than manually applying them? > > I've pulled this into a separate branch, but based on the block branch, > for-6.3/iov-extract. It's added to for-next as well.
This does cause about a 2.7% regression for me, using O_DIRECT on a raw block device. Looking at a perf diff, here's the top:
+2.71% [kernel.vmlinux] [k] mod_node_page_state +2.22% [kernel.vmlinux] [k] iov_iter_extract_pages
and these two are gone:
2.14% [kernel.vmlinux] [k] __iov_iter_get_pages_alloc 1.53% [kernel.vmlinux] [k] iov_iter_get_pages
rest is mostly in the noise, but mod_node_page_state() sticks out like a sore thumb. They seem to be caused by the node stat accounting done in gup.c for FOLL_PIN.
Hmm?
-- Jens Axboe
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