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From: Andrew Morton <akpm@linux-foundation.org>
To: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
	Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>,
	Hugh Dickins <hughd@google.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] mm: use long type for page counts in mm_populate() and get_user_pages()
Date: Wed, 30 Jan 2013 16:42:20 -0800	[thread overview]
Message-ID: <20130130164220.eaebcb6a.akpm@linux-foundation.org> (raw)
In-Reply-To: <1359591980-29542-2-git-send-email-walken@google.com>

On Wed, 30 Jan 2013 16:26:18 -0800
Michel Lespinasse <walken@google.com> wrote:

> Use long type for page counts in mm_populate() so as to avoid integer
> overflow

Would prefer to use unsigned long if we're churning this code.  A "page
count" can never be negative and we avoid the various possible
overflow/signedness issues.

However get_user_pages() and follow_hugetlb_page() return "page count
or -ve errno", so we're somewhat screwed there.  And that's the bulk of
the patch :(

btw, what twit merged a follow_hugetlb_page() which takes an
undocumented argument called "i".  Sigh.

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  reply	other threads:[~2013-01-31  0:42 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-31  0:26 [PATCH 0/3] fixes for large mm_populate() and munlock() operations Michel Lespinasse
2013-01-31  0:26 ` [PATCH 1/3] mm: use long type for page counts in mm_populate() and get_user_pages() Michel Lespinasse
2013-01-31  0:42   ` Andrew Morton [this message]
2013-02-07  0:39   ` Sasha Levin
2013-02-07  1:10     ` Andrew Morton
2013-02-07  1:16       ` Sasha Levin
2013-02-07 21:35       ` Michel Lespinasse
2013-01-31  0:26 ` [PATCH 2/3] mm: accelerate mm_populate() treatment of THP pages Michel Lespinasse
2013-01-31  3:05   ` Hugh Dickins
2013-01-31  4:27     ` Michel Lespinasse
2013-02-02  0:08   ` Andrew Morton
2013-01-31  0:26 ` [RFC PATCH 3/3] mm: accelerate munlock() " Michel Lespinasse

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