From: Andrew Morton <akpm@linux-foundation.org>
To: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>,
Vladimir Davydov <vdavydov@virtuozzo.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.cz>,
Dave Hansen <dave.hansen@intel.com>,
Ying Huang <ying.huang@intel.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [Patch] mm: Increase pagevec size on large system
Date: Tue, 30 Jun 2020 17:27:13 -0700 [thread overview]
Message-ID: <20200630172713.496590a923744c0e0160d36b@linux-foundation.org> (raw)
In-Reply-To: <6260c66e-68a3-ab3e-4bd9-4a290d068e1f@linux.intel.com>
On Mon, 29 Jun 2020 09:57:42 -0700 Tim Chen <tim.c.chen@linux.intel.com> wrote:
>
>
> I am okay with Matthew's suggestion of keeping the stack pagevec size unchanged.
> Andrew, do you have a preference?
>
> I was assuming that for people who really care about saving the kernel memory
> usage, they would make CONFIG_NR_CPUS small. I also have a hard time coming
> up with a better scheme.
>
> Otherwise, we will have to adjust the pagevec size when we actually
> found out how many CPUs we have brought online. It seems like a lot
> of added complexity for going that route.
Even if we were to do this, the worst-case stack usage on the largest
systems might be an issue. If it isn't then we might as well hard-wire
it to 31 elements anyway,
I dunno. An extra 128 bytes of stack doesn't sound toooo bad, and the
performance benefit is significant. Perhaps we just go with the
original patch. If there are any on-stack pagevecs in the page reclaim
path then perhaps we could create a new mini-pagevec for just those. or
look at simply removing the pagevec optimization in there altogether.
next prev parent reply other threads:[~2020-07-01 0:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-26 21:23 Tim Chen
2020-06-27 3:13 ` Matthew Wilcox
2020-06-27 3:47 ` Andrew Morton
2020-06-29 16:57 ` Tim Chen
2020-07-01 0:27 ` Andrew Morton [this message]
2020-07-01 10:05 ` Michal Hocko
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