From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Michal Hocko <mhocko@kernel.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Yang Shi <yang.shi@linux.alibaba.com>,
Vlastimil Babka <vbabka@suse.cz>,
hannes@cmpxchg.org, rientjes@google.com,
akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [v2 PATCH -mm] mm: account deferred split THPs into MemAvailable
Date: Fri, 30 Aug 2019 15:53:04 +0300 [thread overview]
Message-ID: <20190830125304.m6aouvq5ohkerfls@box> (raw)
In-Reply-To: <20190828160224.GP28313@dhcp22.suse.cz>
On Wed, Aug 28, 2019 at 06:02:24PM +0200, Michal Hocko wrote:
> > >
> > > Any idea about a bad case?
> >
> > Not really.
> >
> > How bad you want it to get? How many processes share the page? Access
> > pattern? Locking situation?
>
> Let's say how hard a regular user can make this?
It bumped to ~170 ms if each THP was mapped 5 times.
Adding ptl contention (tight loop of MADV_DONTNEED) in 3 processes that
maps the page, the time to split bumped to ~740ms.
Overally, it's reasonable to take ~100ms per GB of huge pages as rule of
thumb.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2019-08-30 12:53 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-21 17:55 Yang Shi
2019-08-22 8:04 ` Michal Hocko
2019-08-22 12:56 ` Vlastimil Babka
2019-08-22 15:29 ` Kirill A. Shutemov
2019-08-26 7:40 ` Michal Hocko
2019-08-26 13:15 ` Kirill A. Shutemov
2019-08-27 6:01 ` Michal Hocko
2019-08-27 11:02 ` Kirill A. Shutemov
2019-08-27 11:48 ` Michal Hocko
2019-08-27 12:01 ` Vlastimil Babka
2019-08-27 12:09 ` Michal Hocko
2019-08-27 12:17 ` Kirill A. Shutemov
2019-08-27 12:59 ` Kirill A. Shutemov
2019-08-27 17:06 ` Yang Shi
2019-08-28 7:57 ` Michal Hocko
2019-08-28 14:03 ` Kirill A. Shutemov
[not found] ` <20190828141253.GM28313@dhcp22.suse.cz>
2019-08-28 14:46 ` Kirill A. Shutemov
2019-08-28 16:02 ` Michal Hocko
2019-08-29 17:03 ` Yang Shi
2019-08-30 6:23 ` Michal Hocko
2019-08-30 12:53 ` Kirill A. Shutemov [this message]
2019-08-22 15:49 ` Kirill A. Shutemov
2019-08-22 15:57 ` Yang Shi
2019-08-22 15:33 ` Yang Shi
2019-08-26 7:43 ` Michal Hocko
2019-08-27 4:27 ` Yang Shi
2019-08-27 5:59 ` Michal Hocko
2019-08-27 8:32 ` Kirill A. Shutemov
2019-08-27 9:00 ` Michal Hocko
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