From: Minchan Kim <minchan@kernel.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
cgoldswo@codeaurora.org, linux-fsdevel@vger.kernel.org,
david@redhat.com, vbabka@suse.cz, viro@zeniv.linux.org.uk,
joaodias@google.com
Subject: Re: [RFC 1/2] mm: disable LRU pagevec during the migration temporarily
Date: Wed, 17 Feb 2021 13:32:05 -0800 [thread overview]
Message-ID: <YC2LVXO6e2NVsBqz@google.com> (raw)
In-Reply-To: <20210217211612.GO2858050@casper.infradead.org>
On Wed, Feb 17, 2021 at 09:16:12PM +0000, Matthew Wilcox wrote:
> On Wed, Feb 17, 2021 at 12:46:19PM -0800, Minchan Kim wrote:
> > > I suspect you do not want to add atomic_read inside hot paths, right? Is
> > > this really something that we have to microoptimize for? atomic_read is
> > > a simple READ_ONCE on many archs.
> >
> > It's also spin_lock_irq_save in some arch. If the new synchonization is
> > heavily compilcated, atomic would be better for simple start but I thought
> > this locking scheme is too simple so no need to add atomic operation in
> > readside.
>
> What arch uses a spinlock for atomic_read()? I just had a quick grep and
> didn't see any.
Ah, my bad. I was confused with update side.
Okay, let's use atomic op to make it simple.
Thanks for the review, Mattew and Michal.
next prev parent reply other threads:[~2021-02-17 21:34 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-16 17:03 [RFC 1/2] mm: disable LRU pagevec during the migration temporarily Minchan Kim
2021-02-16 17:03 ` [RFC 2/2] mm: fs: Invalidate BH LRU during page migration Minchan Kim
2021-02-16 18:22 ` [RFC 1/2] mm: disable LRU pagevec during the migration temporarily Matthew Wilcox
2021-02-16 21:30 ` Minchan Kim
2021-02-17 8:59 ` Michal Hocko
2021-02-17 9:50 ` Michal Hocko
2021-02-17 20:51 ` Minchan Kim
2021-02-17 21:11 ` Matthew Wilcox
2021-02-17 21:22 ` Minchan Kim
2021-02-17 20:46 ` Minchan Kim
2021-02-17 21:16 ` Matthew Wilcox
2021-02-17 21:32 ` Minchan Kim [this message]
2021-02-18 8:17 ` Michal Hocko
2021-02-18 8:24 ` David Hildenbrand
2021-02-18 15:52 ` Minchan Kim
2021-02-18 16:08 ` Michal Hocko
2021-02-18 16:21 ` Minchan Kim
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