From: Dave Hansen <dave@sr71.net>
To: Christoph Lameter <cl@linux.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, penberg@kernel.org
Subject: Re: [RFC][PATCH 5/9] mm: rearrange struct page
Date: Thu, 16 Jan 2014 14:29:07 -0800 [thread overview]
Message-ID: <52D85D33.4080509@sr71.net> (raw)
In-Reply-To: <alpine.DEB.2.10.1401161233060.30036@nuc>
On 01/16/2014 10:34 AM, Christoph Lameter wrote:
> On Tue, 14 Jan 2014, Dave Hansen wrote:
>> This makes it *MUCH* more clear how the first few fields of
>> 'struct page' get used by the slab allocators.
>
> I think this adds to the confusion. What you want to know is which other
> fields overlap a certain field. After this patch you wont have that
> anymore.
Why does it matter *specifically* that "index shares space with
freelist", or that "mapping shares space with s_mem"? No data is ever
handed off in those fields.
All that matters is that we know the _set_ of fields that gets reused,
and that we preserve the ones which *need* their contents preserved
(only flags and _count as far as I can tell).
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WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave@sr71.net>
To: Christoph Lameter <cl@linux.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, penberg@kernel.org
Subject: Re: [RFC][PATCH 5/9] mm: rearrange struct page
Date: Thu, 16 Jan 2014 14:29:07 -0800 [thread overview]
Message-ID: <52D85D33.4080509@sr71.net> (raw)
In-Reply-To: <alpine.DEB.2.10.1401161233060.30036@nuc>
On 01/16/2014 10:34 AM, Christoph Lameter wrote:
> On Tue, 14 Jan 2014, Dave Hansen wrote:
>> This makes it *MUCH* more clear how the first few fields of
>> 'struct page' get used by the slab allocators.
>
> I think this adds to the confusion. What you want to know is which other
> fields overlap a certain field. After this patch you wont have that
> anymore.
Why does it matter *specifically* that "index shares space with
freelist", or that "mapping shares space with s_mem"? No data is ever
handed off in those fields.
All that matters is that we know the _set_ of fields that gets reused,
and that we preserve the ones which *need* their contents preserved
(only flags and _count as far as I can tell).
next prev parent reply other threads:[~2014-01-16 22:30 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-14 18:00 [RFC][PATCH 0/9] re-shrink 'struct page' when SLUB is on Dave Hansen
2014-01-14 18:00 ` Dave Hansen
2014-01-14 18:00 ` [RFC][PATCH 1/9] mm: slab/slub: use page->list consistently instead of page->lru Dave Hansen
2014-01-14 18:00 ` Dave Hansen
2014-01-14 19:31 ` Christoph Lameter
2014-01-14 19:31 ` Christoph Lameter
2014-01-15 2:31 ` David Rientjes
2014-01-15 2:31 ` David Rientjes
2014-01-15 6:58 ` Dave Hansen
2014-01-15 6:58 ` Dave Hansen
2014-01-15 7:16 ` David Rientjes
2014-01-15 7:16 ` David Rientjes
2014-01-16 0:11 ` Kirill A. Shutemov
2014-01-16 0:11 ` Kirill A. Shutemov
2014-01-14 18:00 ` [RFC][PATCH 2/9] mm: slub: abstract out double cmpxchg option Dave Hansen
2014-01-14 18:00 ` Dave Hansen
2014-01-14 19:49 ` Christoph Lameter
2014-01-14 19:49 ` Christoph Lameter
2014-01-14 21:41 ` Dave Hansen
2014-01-14 21:41 ` Dave Hansen
2014-01-15 2:37 ` David Rientjes
2014-01-15 2:37 ` David Rientjes
2014-01-16 16:45 ` Christoph Lameter
2014-01-16 16:45 ` Christoph Lameter
2014-01-16 17:13 ` Dave Hansen
2014-01-16 17:13 ` Dave Hansen
2014-01-14 18:00 ` [RFC][PATCH 3/9] mm: page->pfmemalloc only used by slab/skb Dave Hansen
2014-01-14 18:00 ` Dave Hansen
2014-01-14 19:49 ` Christoph Lameter
2014-01-14 19:49 ` Christoph Lameter
2014-01-14 22:17 ` Dave Hansen
2014-01-14 22:17 ` Dave Hansen
2014-01-15 2:45 ` David Rientjes
2014-01-15 2:45 ` David Rientjes
2014-01-16 0:16 ` Kirill A. Shutemov
2014-01-16 0:16 ` Kirill A. Shutemov
2014-01-14 18:00 ` [RFC][PATCH 4/9] mm: slabs: reset page at free Dave Hansen
2014-01-14 18:00 ` Dave Hansen
2014-01-15 2:48 ` David Rientjes
2014-01-15 2:48 ` David Rientjes
2014-01-16 18:35 ` Dave Hansen
2014-01-16 18:35 ` Dave Hansen
2014-01-16 18:32 ` Christoph Lameter
2014-01-16 18:32 ` Christoph Lameter
2014-01-14 18:00 ` [RFC][PATCH 5/9] mm: rearrange struct page Dave Hansen
2014-01-14 18:00 ` Dave Hansen
2014-01-16 0:20 ` Kirill A. Shutemov
2014-01-16 0:20 ` Kirill A. Shutemov
2014-01-16 18:34 ` Christoph Lameter
2014-01-16 18:34 ` Christoph Lameter
2014-01-16 22:29 ` Dave Hansen [this message]
2014-01-16 22:29 ` Dave Hansen
2014-01-17 14:58 ` Christoph Lameter
2014-01-17 14:58 ` Christoph Lameter
2014-01-14 18:01 ` [RFC][PATCH 6/9] mm: slub: rearrange 'struct page' fields Dave Hansen
2014-01-14 18:01 ` Dave Hansen
2014-01-14 18:01 ` [RFC][PATCH 7/9] mm: slub: remove 'struct page' alignment restrictions Dave Hansen
2014-01-14 18:01 ` Dave Hansen
2014-01-14 18:01 ` [RFC][PATCH 8/9] mm: slub: cleanups after code churn Dave Hansen
2014-01-14 18:01 ` Dave Hansen
2014-01-14 18:01 ` [RFC][PATCH 9/9] mm: fix alignment checks on 32-bit Dave Hansen
2014-01-14 18:01 ` Dave Hansen
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