From: Matthew Wilcox <willy@infradead.org>
To: Harish Mara <Harish.Mara@ibm.com>
Cc: linux-mm@kvack.org, Aniket Kulkarni <aniket.kulkarni@us.ibm.com>,
Pawan Powar <ppowar@us.ibm.com>,
Rajshekar Iyer <iyerr@us.ibm.com>,
ask@linux.vnet.ibm.com
Subject: Re: Question regarding map count for compound pages
Date: Tue, 16 Nov 2021 03:40:05 +0000 [thread overview]
Message-ID: <YZMoFc+21TTFsJ3Y@casper.infradead.org> (raw)
In-Reply-To: <OF77A59952.F23E0FCF-ON0025878F.000F1EF4-8525878F.000F4A65@ibm.com>
On Mon, Nov 15, 2021 at 10:47:01PM -0400, Harish Mara wrote:
> Background:
> On older kernel?s, we could have our device driver create char devices and
Which device driver is this?
> It looks like the culprit is zap_pte_range(), which calls
> page_remove_rmap() with the compound_flag = false. As a result, instead of
> decrementing the compound_mapcount for the page the page->_mapcount is
> decremented causing a lot of bad page errors.
There is a lot of confusion in the core MM between 'compound page'
and 'PMD allocation'. I'm trying to fix it; do you have time to help?
prev parent reply other threads:[~2021-11-16 3:40 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-16 2:47 Question regarding map count for compound pages Harish Mara
2021-11-16 3:31 ` John Donnelly
2021-11-16 3:40 ` Matthew Wilcox [this message]
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