From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-mm@kvack.org, Matthew Wilcox <mawilcox@microsoft.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
linux-kernel@vger.kernel.org,
Fengguang Wu <fengguang.wu@intel.com>,
linux-api@vger.kernel.org
Subject: Re: [PATCH v4 2/4] mm: Split page_type out from _map_count
Date: Fri, 2 Mar 2018 11:18:06 +0300 [thread overview]
Message-ID: <20180302081806.aokjrb27hxqki7at@node.shutemov.name> (raw)
In-Reply-To: <20180301211523.21104-3-willy@infradead.org>
On Thu, Mar 01, 2018 at 01:15:21PM -0800, Matthew Wilcox wrote:
> From: Matthew Wilcox <mawilcox@microsoft.com>
>
> We're already using a union of many fields here, so stop abusing the
> _map_count and make page_type its own field. That implies renaming some
s/_map_count/_mapcount/
and in subject.
> of the machinery that creates PageBuddy, PageBalloon and PageKmemcg;
> bring back the PG_buddy, PG_balloon and PG_kmemcg names.
>
> As suggested by Kirill, make page_type a bitmask. Because it starts out
> life as -1 (thanks to sharing the storage with _map_count), setting a
> page flag means clearing the appropriate bit. This gives us space for
> probably twenty or so extra bits (depending how paranoid we want to be
> about _mapcount underflow).
>
> Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
--
Kirill A. Shutemov
next prev parent reply other threads:[~2018-03-02 8:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-01 21:15 [PATCH v4 0/4] Record additional page allocation reasons Matthew Wilcox
2018-03-01 21:15 ` [PATCH v4 1/4] s390: Use _refcount for pgtables Matthew Wilcox
2018-03-01 21:15 ` [PATCH v4 2/4] mm: Split page_type out from _map_count Matthew Wilcox
2018-03-02 8:18 ` Kirill A. Shutemov [this message]
2018-03-01 21:15 ` [PATCH v4 3/4] mm: Mark pages allocated through vmalloc Matthew Wilcox
2018-03-02 8:20 ` Kirill A. Shutemov
2018-03-01 21:15 ` [PATCH v4 4/4] mm: Mark pages in use for page tables Matthew Wilcox
2018-03-02 8:21 ` Kirill A. Shutemov
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