From: Chris Goldsworthy <cgoldswo@codeaurora.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>,
viro@zeniv.linux.org.uk, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Laura Abbott <lauraa@codeaurora.org>
Subject: Re: [PATCH v4] fs/buffer.c: Revoke LRU when trying to drop buffers
Date: Thu, 28 Jan 2021 00:28:37 -0800 [thread overview]
Message-ID: <4d034ea4228be568db62243bfe238e0d@codeaurora.org> (raw)
In-Reply-To: <20210127025922.GS308988@casper.infradead.org>
On 2021-01-26 18:59, Matthew Wilcox wrote:
> On Tue, Jan 26, 2021 at 02:59:17PM -0800, Minchan Kim wrote:
>> The release buffer_head in LRU is great improvement for migration
>> point of view.
>>
>> A question:
Hey guys,
>> Can't we invalidate(e.g., invalidate_bh_lrus) bh_lru in migrate_prep
>> or
>> elsewhere when migration found the failure and is about to retry?
>>
>> Migration has done such a way for other per-cpu stuffs for a long
>> time,
>> which would be more consistent with others and might be faster
>> sometimes
>> with reducing IPI calls for page.
> Should lru_add_drain_all() also handle draining the buffer lru for all
> callers? A quick survey ...
>
> invalidate_bdev() already calls invalidate_bh_lrus()
> compact_nodes() would probably benefit from the BH LRU being
> invalidated
> POSIX_FADV_DONTNEED would benefit if the underlying filesystem uses BHs
> check_and_migrate_cma_pages() would benefit
> khugepaged_do_scan() doesn't need it today
> scan_get_next_rmap_item() looks like it only works on anon pages (?) so
> doesn't need it
> mem_cgroup_force_empty() probably needs it
> mem_cgroup_move_charge() ditto
> memfd_wait_for_pins() doesn't need it
> shake_page() might benefit
> offline_pages() would benefit
> alloc_contig_range() would benefit
>
> Seems like most would benefit and a few won't care. I think I'd lean
> towards having lru_add_drain_all() call invalidate_bh_lrus(), just to
> simplify things.
Doing this sounds like a good idea. We would still need a call to
invalidate_bh_lrus() inside of drop_buffers() in the event that we find
busy buffers, since they can be re-added back into the BH LRU - I
believe
it isn't until this point that a BH can't be added back into the BH LRU,
when we acquire the private_lock for the mapping:
https://elixir.bootlin.com/linux/v5.10.10/source/fs/buffer.c#L3240
Thanks,
Chris.
--
The Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
Forum,
a Linux Foundation Collaborative Project
next prev parent reply other threads:[~2021-01-28 8:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-26 6:58 [PATCH v4] Resolve LRU page-pinning issue for file-backed pages Chris Goldsworthy
2021-01-26 6:58 ` [PATCH v4] fs/buffer.c: Revoke LRU when trying to drop buffers Chris Goldsworthy
2021-01-26 22:59 ` Minchan Kim
2021-01-27 2:59 ` Matthew Wilcox
2021-01-27 17:01 ` Minchan Kim
2021-01-28 8:28 ` Chris Goldsworthy [this message]
2021-01-28 17:08 ` Minchan Kim
2021-01-28 18:43 ` Chris Goldsworthy
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4d034ea4228be568db62243bfe238e0d@codeaurora.org \
--to=cgoldswo@codeaurora.org \
--cc=lauraa@codeaurora.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=minchan@kernel.org \
--cc=viro@zeniv.linux.org.uk \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).