From: Christoph Lameter <cl@linux.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
David Rientjes <rientjes@google.com>,
Dave Hansen <dave.hansen@intel.com>, Mel Gorman <mgorman@suse.de>,
Rik van Riel <riel@redhat.com>, Vlastimil Babka <vbabka@suse.cz>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Steve Capper <steve.capper@linaro.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.cz>,
Jerome Marchand <jmarchan@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: page-flags behavior on compound pages: a worry
Date: Mon, 10 Aug 2015 08:50:10 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.11.1508100847450.3021@east.gentwo.org> (raw)
In-Reply-To: <20150810110955.GA27046@node.dhcp.inet.fi>
On Mon, 10 Aug 2015, Kirill A. Shutemov wrote:
> I don't see anything actionable here. Your wish list doesn't cope with
> reality. Compound pages are mapped with PTEs for almost ten years and I
> don't see why we should stop the practice.
Well they have to if they are smaller than huge pages. Treating each PTE
as each having their own state instead of having the whole compound mapped
completely causes the problem. Refcounting in tail pages is not necessary
if the whole compound is either mapped or not mapped at all by a process.
Refcounting in tail pages is only necessary if you allow 4k slices to be
mapped.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Lameter <cl@linux.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
David Rientjes <rientjes@google.com>,
Dave Hansen <dave.hansen@intel.com>, Mel Gorman <mgorman@suse.de>,
Rik van Riel <riel@redhat.com>, Vlastimil Babka <vbabka@suse.cz>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Steve Capper <steve.capper@linaro.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.cz>,
Jerome Marchand <jmarchan@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: page-flags behavior on compound pages: a worry
Date: Mon, 10 Aug 2015 08:50:10 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.11.1508100847450.3021@east.gentwo.org> (raw)
In-Reply-To: <20150810110955.GA27046@node.dhcp.inet.fi>
On Mon, 10 Aug 2015, Kirill A. Shutemov wrote:
> I don't see anything actionable here. Your wish list doesn't cope with
> reality. Compound pages are mapped with PTEs for almost ten years and I
> don't see why we should stop the practice.
Well they have to if they are smaller than huge pages. Treating each PTE
as each having their own state instead of having the whole compound mapped
completely causes the problem. Refcounting in tail pages is not necessary
if the whole compound is either mapped or not mapped at all by a process.
Refcounting in tail pages is only necessary if you allow 4k slices to be
mapped.
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next prev parent reply other threads:[~2015-08-10 13:50 UTC|newest]
Thread overview: 117+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-19 17:08 [PATCH 00/16] Sanitize usage of ->flags and ->mapping for tail pages Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-19 17:08 ` [PATCH 01/16] mm: consolidate all page-flags helpers in <linux/page-flags.h> Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-23 0:10 ` Hugh Dickins
2015-03-23 0:10 ` Hugh Dickins
2015-03-19 17:08 ` [PATCH 02/16] page-flags: trivial cleanup for PageTrans* helpers Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-23 0:12 ` Hugh Dickins
2015-03-23 0:12 ` Hugh Dickins
2015-03-19 17:08 ` [PATCH 03/16] page-flags: introduce page flags policies wrt compound pages Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-20 20:35 ` Andrew Morton
2015-03-20 20:35 ` Andrew Morton
2015-03-20 21:34 ` Kirill A. Shutemov
2015-03-20 21:34 ` Kirill A. Shutemov
2015-03-19 17:08 ` [PATCH 04/16] page-flags: define PG_locked behavior on " Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-27 15:11 ` Mateusz Krawczuk
2015-03-27 15:11 ` Mateusz Krawczuk
2015-03-27 15:13 ` Mateusz Krawczuk
2015-03-27 15:13 ` Mateusz Krawczuk
2015-03-27 15:13 ` Mateusz Krawczuk
2015-03-27 16:37 ` Kirill A. Shutemov
2015-03-27 16:37 ` Kirill A. Shutemov
2015-03-27 16:37 ` Kirill A. Shutemov
2015-07-15 20:20 ` Christoph Lameter
2015-07-15 20:20 ` Christoph Lameter
2015-08-06 4:15 ` page-flags behavior on compound pages: a worry Hugh Dickins
2015-08-06 4:15 ` Hugh Dickins
2015-08-06 15:33 ` Kirill A. Shutemov
2015-08-06 15:33 ` Kirill A. Shutemov
2015-08-06 19:24 ` Hugh Dickins
2015-08-06 19:24 ` Hugh Dickins
2015-08-06 20:45 ` Christoph Lameter
2015-08-06 20:45 ` Christoph Lameter
2015-08-07 14:50 ` Kirill A. Shutemov
2015-08-07 14:50 ` Kirill A. Shutemov
2015-08-07 15:28 ` Christoph Lameter
2015-08-07 15:28 ` Christoph Lameter
2015-08-10 11:09 ` Kirill A. Shutemov
2015-08-10 11:09 ` Kirill A. Shutemov
2015-08-10 13:50 ` Christoph Lameter [this message]
2015-08-10 13:50 ` Christoph Lameter
2015-08-07 14:49 ` Kirill A. Shutemov
2015-08-07 14:49 ` Kirill A. Shutemov
2015-08-13 5:10 ` Hugh Dickins
2015-08-13 5:10 ` Hugh Dickins
2015-08-12 14:35 ` Kirill A. Shutemov
2015-08-12 14:35 ` Kirill A. Shutemov
2015-08-12 14:47 ` Vlastimil Babka
2015-08-12 14:47 ` Vlastimil Babka
2015-08-12 21:16 ` Andrew Morton
2015-08-12 21:16 ` Andrew Morton
2015-08-12 22:21 ` Kirill A. Shutemov
2015-08-12 22:21 ` Kirill A. Shutemov
2015-08-13 4:12 ` Hugh Dickins
2015-08-13 4:12 ` Hugh Dickins
2015-03-19 17:08 ` [PATCH 05/16] page-flags: define behavior of FS/IO-related flags on compound pages Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-19 18:29 ` Dave Hansen
2015-03-19 18:29 ` Dave Hansen
2015-03-19 20:02 ` Kirill A. Shutemov
2015-03-19 20:02 ` Kirill A. Shutemov
2015-03-23 0:02 ` Hugh Dickins
2015-03-23 0:02 ` Hugh Dickins
2015-03-23 12:17 ` Kirill A. Shutemov
2015-03-23 12:17 ` Kirill A. Shutemov
2015-03-24 22:54 ` Hugh Dickins
2015-03-24 22:54 ` Hugh Dickins
2015-03-25 10:23 ` Kirill A. Shutemov
2015-03-25 10:23 ` Kirill A. Shutemov
2015-03-25 18:56 ` Hugh Dickins
2015-03-25 18:56 ` Hugh Dickins
2015-03-19 17:08 ` [PATCH 06/16] page-flags: define behavior of LRU-related " Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-19 17:08 ` [PATCH 07/16] page-flags: define behavior SL*B-related " Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-19 17:08 ` [PATCH 08/16] page-flags: define behavior of Xen-related " Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-19 17:08 ` [PATCH 09/16] page-flags: define PG_reserved behavior " Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2020-01-31 15:24 ` Chris Wilson
2020-02-03 15:18 ` Kirill A. Shutemov
2020-02-03 15:24 ` Chris Wilson
2020-02-03 17:10 ` David Hildenbrand
2020-02-03 17:29 ` Christoph Hellwig
2015-03-19 17:08 ` [PATCH 10/16] page-flags: define PG_swapbacked " Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-19 17:08 ` [PATCH 11/16] page-flags: define PG_swapcache " Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-19 17:08 ` [PATCH 12/16] page-flags: define PG_mlocked " Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-19 17:08 ` [PATCH 13/16] page-flags: define PG_uncached " Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-19 17:08 ` [PATCH 14/16] page-flags: define PG_uptodate " Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-19 17:08 ` [PATCH 15/16] page-flags: look on head page if the flag is encoded in page->mapping Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-19 17:08 ` [PATCH 16/16] mm: sanitize page->mapping for tail pages Kirill A. Shutemov
2015-03-19 17:08 ` Kirill A. Shutemov
2015-03-23 0:28 ` [PATCH 00/16] Sanitize usage of ->flags and ->mapping " Hugh Dickins
2015-03-23 0:28 ` Hugh Dickins
2015-03-23 10:04 ` Kirill A. Shutemov
2015-03-23 10:04 ` Kirill A. Shutemov
2015-03-24 23:42 ` Hugh Dickins
2015-03-24 23:42 ` Hugh Dickins
2015-03-25 10:55 ` Kirill A. Shutemov
2015-03-25 10:55 ` Kirill A. Shutemov
2015-03-24 17:39 ` Konstantin Khlebnikov
2015-03-24 17:39 ` Konstantin Khlebnikov
2015-03-24 20:04 ` Kirill A. Shutemov
2015-03-24 20:04 ` Kirill A. Shutemov
2015-07-15 20:20 ` Christoph Lameter
2015-07-15 20:20 ` Christoph Lameter
2015-07-15 21:18 ` Kirill A. Shutemov
2015-07-15 21:18 ` Kirill A. Shutemov
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