From: Michal Hocko <mhocko@suse.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@redhat.com>,
linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
John Dias <joaodias@google.com>
Subject: Re: [RESEND][PATCH v2] mm: don't call lru draining in the nested lru_cache_disable
Date: Fri, 21 Jan 2022 10:59:32 +0100 [thread overview]
Message-ID: <YeqEBAKJ6NUjLQhr@dhcp22.suse.cz> (raw)
In-Reply-To: <YenPK/JVNOhbxjtr@google.com>
On Thu 20-01-22 13:07:55, Minchan Kim wrote:
> On Thu, Jan 20, 2022 at 09:24:22AM +0100, Michal Hocko wrote:
> > On Wed 19-01-22 20:25:54, Minchan Kim wrote:
> > > On Wed, Jan 19, 2022 at 10:20:22AM +0100, Michal Hocko wrote:
> > [...]
> > > > What does prevent you from calling lru_cache_{disable,enable} this way
> > > > with the existing implementation? AFAICS calls can be nested just fine.
> > > > Or am I missing something?
> > >
> > > It just increases more IPI calls since we drain the lru cache
> > > both upper layer and lower layer. That's I'd like to avoid
> > > in this patch. Just disable lru cache one time for entire
> > > allocation path.
> >
> > I do not follow. Once you call lru_cache_disable at the higher level
> > then no new pages are going to be added to the pcp caches. At the same
> > time existing caches are flushed so the inner lru_cache_disable will not
> > trigger any new IPIs.
>
> lru_cache_disable calls __lru_add_drain_all with force_all_cpus
> unconditionally so keep calling the IPI.
OK, this is something I have missed. Why cannot we remove the force_all
mode for lru_disable_count>0 when there are no pcp caches populated?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2022-01-21 9:59 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-30 19:36 [RESEND][PATCH v2] mm: don't call lru draining in the nested lru_cache_disable Minchan Kim
2022-01-06 18:14 ` Minchan Kim
2022-01-17 13:47 ` Michal Hocko
2022-01-19 0:12 ` Minchan Kim
2022-01-19 9:20 ` Michal Hocko
2022-01-20 4:25 ` Minchan Kim
2022-01-20 8:24 ` Michal Hocko
2022-01-20 21:07 ` Minchan Kim
2022-01-21 9:59 ` Michal Hocko [this message]
2022-01-21 21:56 ` Minchan Kim
2022-01-24 9:57 ` Michal Hocko
2022-01-24 22:22 ` Minchan Kim
2022-01-25 9:23 ` Michal Hocko
2022-01-25 21:06 ` Minchan Kim
2022-01-26 12:09 ` Michal Hocko
2022-01-20 8:42 ` David Hildenbrand
2022-01-20 21:22 ` Minchan Kim
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=YeqEBAKJ6NUjLQhr@dhcp22.suse.cz \
--to=mhocko@suse.com \
--cc=akpm@linux-foundation.org \
--cc=david@redhat.com \
--cc=joaodias@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=minchan@kernel.org \
--cc=surenb@google.com \
/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).