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From: "H. Peter Anvin" <hpa@zytor.com>
To: Christoph Lameter <cl@linux.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
	Pekka Enberg <penberg@cs.helsinki.fi>,
	David Rientjes <rientjes@google.com>,
	linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [slubllv7 06/17] slub: Add cmpxchg_double_slab()
Date: Tue, 12 Jul 2011 11:40:45 -0700	[thread overview]
Message-ID: <4E1C952D.6010902@zytor.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1107121146080.3937@router.home>

On 07/12/2011 09:47 AM, Christoph Lameter wrote:
> On Tue, 12 Jul 2011, Eric Dumazet wrote:
> 
>> Le mardi 12 juillet 2011 à 10:59 -0500, Christoph Lameter a écrit :
>>
>>> We do not need to have _count included. This is just there because the
>>> field is in the way on 64 bit and we can only do 2x 64 bit cmpxchges.  On
>>> 32 bi we can drop _count from "counters".
>>
>> OK, thanks for clarification.
> 
> Still I'd like to get some ideas on how to make the whole thing much
> cleaner. Isnt there some way to convert a struct to an unsigned long
> without going through a union? And a way to convert a struct + 32 bit
> atomic_t into a 64 bit unsigned long? Would simplify things significantly.

If you know it is in memory you can cast ("pun") the pointer.

If it's not in memory that can be inefficient, though.

	-hpa

  reply	other threads:[~2011-07-12 18:47 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-01 17:25 [slubllv7 00/17] SLUB: Lockless freelists for objects V7 Christoph Lameter
2011-06-01 17:25 ` [slubllv7 01/17] slub: Push irq disable into allocate_slab() Christoph Lameter
2011-06-01 17:25 ` [slubllv7 02/17] slub: Do not use frozen page flag but a bit in the page counters Christoph Lameter
2011-06-01 17:25 ` [slubllv7 03/17] slub: Move page->frozen handling near where the page->freelist handling occurs Christoph Lameter
2011-06-01 17:25 ` [slubllv7 04/17] x86: Add support for cmpxchg_double Christoph Lameter
2011-06-09  9:53   ` Pekka Enberg
2011-06-10 15:17     ` Christoph Lameter
2011-06-11  9:50       ` Pekka Enberg
2011-06-11 17:02         ` Christoph Lameter
2011-06-14  5:49           ` Pekka Enberg
2011-06-14  8:04             ` Ingo Molnar
2011-06-14 14:04               ` Christoph Lameter
2011-06-14 15:05                 ` H. Peter Anvin
2011-06-15  8:55   ` Tejun Heo
2011-06-15 14:26     ` Christoph Lameter
2011-06-15 16:39       ` Tejun Heo
2011-06-15 17:19         ` Christoph Lameter
2011-06-25 23:49   ` [tip:x86/atomic] " tip-bot for Christoph Lameter
2011-06-01 17:25 ` [slubllv7 05/17] mm: Rearrange struct page Christoph Lameter
2011-06-09  9:57   ` Pekka Enberg
2011-06-09 16:45     ` Andrew Morton
2011-06-09 17:03       ` [PATCH] checkpatch: Add a "prefer __aligned" check Joe Perches
2011-06-01 17:25 ` [slubllv7 06/17] slub: Add cmpxchg_double_slab() Christoph Lameter
2011-07-11 19:55   ` Eric Dumazet
2011-07-12 15:59     ` Christoph Lameter
2011-07-12 16:06       ` Eric Dumazet
2011-07-12 16:47         ` Christoph Lameter
2011-07-12 18:40           ` H. Peter Anvin [this message]
2011-07-12 18:53             ` Christoph Lameter
2011-07-12 20:40               ` H. Peter Anvin
2011-06-01 17:25 ` [slubllv7 07/17] slub: explicit list_lock taking Christoph Lameter
2011-06-01 17:25 ` [slubllv7 08/17] slub: Pass kmem_cache struct to lock and freeze slab Christoph Lameter
2011-06-01 17:25 ` [slubllv7 09/17] slub: Rework allocator fastpaths Christoph Lameter
2011-06-01 17:25 ` [slubllv7 10/17] slub: Invert locking and avoid slab lock Christoph Lameter
2011-06-01 17:25 ` [slubllv7 11/17] slub: Disable interrupts in free_debug processing Christoph Lameter
2011-06-01 17:25 ` [slubllv7 12/17] slub: Avoid disabling interrupts in free slowpath Christoph Lameter
2011-06-01 17:25 ` [slubllv7 13/17] slub: Get rid of the another_slab label Christoph Lameter
2011-06-01 17:25 ` [slubllv7 14/17] slub: Add statistics for the case that the current slab does not match the node Christoph Lameter
2011-06-01 17:25 ` [slubllv7 15/17] slub: fast release on full slab Christoph Lameter
2011-06-01 17:25 ` [slubllv7 16/17] slub: Not necessary to check for empty slab on load_freelist Christoph Lameter
2011-06-01 17:26 ` [slubllv7 17/17] slub: slabinfo update for cmpxchg handling Christoph Lameter

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