From: kirill@shutemov.name (Kirill A. Shutemov)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC V2] mm:add zero_page _mapcount when mapped into user space
Date: Tue, 2 Dec 2014 13:30:14 +0200 [thread overview]
Message-ID: <20141202113014.GA22683@node.dhcp.inet.fi> (raw)
In-Reply-To: <35FD53F367049845BC99AC72306C23D103E688B313E0@CNBJMBX05.corpusers.net>
On Tue, Dec 02, 2014 at 05:27:36PM +0800, Wang, Yalin wrote:
> This patch add/dec zero_page's _mapcount to make sure
> the mapcount is correct for zero_page,
> so that when read from /proc/kpagecount, zero_page's
> mapcount is also correct, userspace process like procrank can
> calculate PSS correctly.
I don't have specific code path to point to, but I would expect zero page
with non-zero mapcount would cause a problem with rmap.
How do you test the change?
--
Kirill A. Shutemov
WARNING: multiple messages have this Message-ID (diff)
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: "Wang, Yalin" <Yalin.Wang@sonymobile.com>
Cc: "'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>,
"'linux-mm@kvack.org'" <linux-mm@kvack.org>,
"'linux-arm-kernel@lists.infradead.org'"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC V2] mm:add zero_page _mapcount when mapped into user space
Date: Tue, 2 Dec 2014 13:30:14 +0200 [thread overview]
Message-ID: <20141202113014.GA22683@node.dhcp.inet.fi> (raw)
In-Reply-To: <35FD53F367049845BC99AC72306C23D103E688B313E0@CNBJMBX05.corpusers.net>
On Tue, Dec 02, 2014 at 05:27:36PM +0800, Wang, Yalin wrote:
> This patch add/dec zero_page's _mapcount to make sure
> the mapcount is correct for zero_page,
> so that when read from /proc/kpagecount, zero_page's
> mapcount is also correct, userspace process like procrank can
> calculate PSS correctly.
I don't have specific code path to point to, but I would expect zero page
with non-zero mapcount would cause a problem with rmap.
How do you test the change?
--
Kirill A. Shutemov
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WARNING: multiple messages have this Message-ID (diff)
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: "Wang, Yalin" <Yalin.Wang@sonymobile.com>
Cc: "'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>,
"'linux-mm@kvack.org'" <linux-mm@kvack.org>,
"'linux-arm-kernel@lists.infradead.org'"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC V2] mm:add zero_page _mapcount when mapped into user space
Date: Tue, 2 Dec 2014 13:30:14 +0200 [thread overview]
Message-ID: <20141202113014.GA22683@node.dhcp.inet.fi> (raw)
In-Reply-To: <35FD53F367049845BC99AC72306C23D103E688B313E0@CNBJMBX05.corpusers.net>
On Tue, Dec 02, 2014 at 05:27:36PM +0800, Wang, Yalin wrote:
> This patch add/dec zero_page's _mapcount to make sure
> the mapcount is correct for zero_page,
> so that when read from /proc/kpagecount, zero_page's
> mapcount is also correct, userspace process like procrank can
> calculate PSS correctly.
I don't have specific code path to point to, but I would expect zero page
with non-zero mapcount would cause a problem with rmap.
How do you test the change?
--
Kirill A. Shutemov
next prev parent reply other threads:[~2014-12-02 11:30 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-02 9:27 [RFC V2] mm:add zero_page _mapcount when mapped into user space Wang, Yalin
2014-12-02 9:27 ` Wang, Yalin
2014-12-02 9:27 ` Wang, Yalin
2014-12-02 11:30 ` Kirill A. Shutemov [this message]
2014-12-02 11:30 ` Kirill A. Shutemov
2014-12-02 11:30 ` Kirill A. Shutemov
2014-12-04 6:10 ` Wang, Yalin
2014-12-04 6:10 ` Wang, Yalin
2014-12-04 6:10 ` Wang, Yalin
2014-12-04 12:28 ` Kirill A. Shutemov
2014-12-04 12:28 ` Kirill A. Shutemov
2014-12-04 12:28 ` Kirill A. Shutemov
2014-12-05 6:39 ` Konstantin Khlebnikov
2014-12-05 6:39 ` Konstantin Khlebnikov
2014-12-05 6:39 ` Konstantin Khlebnikov
2014-12-05 8:08 ` Wang, Yalin
2014-12-05 8:08 ` Wang, Yalin
2014-12-05 8:08 ` Wang, Yalin
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