From: Andrea Arcangeli <aarcange@redhat.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Michel Lespinasse <walken@google.com>,
Minchan Kim <minchan.kim@gmail.com>,
Hugh Dickins <hughd@google.com>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>,
Johannes Weiner <jweiner@redhat.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Shaohua Li <shaohua.li@intel.com>
Subject: Re: [RFC PATCH 0/3] page count lock for simpler put_page
Date: Sun, 14 Aug 2011 01:56:11 +0200 [thread overview]
Message-ID: <20110813235611.GA16581@redhat.com> (raw)
In-Reply-To: <20110813015741.GZ2395@linux.vnet.ibm.com>
On Fri, Aug 12, 2011 at 06:57:41PM -0700, Paul E. McKenney wrote:
> But if we are getting much below 100 milliseconds, we need to rethink
> this.
The delay may be low in some corner case but this still benefits by
running it only once. You can mmap() bzero, mremap(+4096) (if mremap
moves the pages to a not aligned 2m address, it forces a
split_huge_page, an hardware issue) and all pages will be splitted in
potentially less than 100msec if they're only a few. At least we'll be
running synchronize_rcu only once instead of for every hugepage, as
long as it runs only once I guess we're ok. Normally it shouldn't
happen so fast. My current /proc/vmstat says there are 271 splits for
97251 THP allocated and they're not so likely to have happened within
100msec.
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next prev parent reply other threads:[~2011-08-13 23:56 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-04 21:07 [RFC PATCH 0/3] page count lock for simpler put_page Michel Lespinasse
2011-08-04 21:07 ` [RFC PATCH 1/3] mm: Replace naked page->_count accesses with accessor functions Michel Lespinasse
2011-08-04 21:07 ` [RFC PATCH 2/3] mm: page count lock Michel Lespinasse
2011-08-07 14:00 ` Minchan Kim
2011-08-04 21:07 ` [RFC PATCH 3/3] mm: get_first_page_unless_zero() Michel Lespinasse
2011-08-07 14:13 ` Minchan Kim
2011-08-05 6:39 ` [RFC PATCH 0/3] page count lock for simpler put_page Michel Lespinasse
2011-08-07 14:25 ` Minchan Kim
2011-08-09 11:04 ` Michel Lespinasse
2011-08-09 22:22 ` Minchan Kim
2011-08-12 22:35 ` Michel Lespinasse
2011-08-13 4:07 ` Minchan Kim
2011-08-12 15:36 ` Andrea Arcangeli
2011-08-12 16:08 ` SPAM: " Paul E. McKenney
2011-08-12 16:43 ` Andrea Arcangeli
2011-08-12 17:27 ` Paul E. McKenney
2011-08-12 23:45 ` Michel Lespinasse
2011-08-13 1:57 ` Paul E. McKenney
2011-08-13 23:56 ` Andrea Arcangeli [this message]
2011-08-13 4:18 ` Minchan Kim
2011-08-12 16:57 ` Johannes Weiner
2011-08-12 17:08 ` Andrea Arcangeli
2011-08-12 17:52 ` Johannes Weiner
2011-08-12 18:13 ` Paul E. McKenney
2011-08-12 19:05 ` Johannes Weiner
2011-08-12 22:14 ` Paul E. McKenney
2011-08-12 22:22 ` Andrea Arcangeli
2011-08-12 18:03 ` Paul E. McKenney
2011-08-12 17:41 ` Paul E. McKenney
2011-08-12 17:56 ` Johannes Weiner
2011-08-12 23:02 ` Michel Lespinasse
2011-08-12 22:50 ` Michel Lespinasse
2011-08-13 4:11 ` Minchan Kim
2011-08-12 16:58 ` Andrea Arcangeli
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