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From: Christoph Hellwig <hch@infradead.org>
To: Alexey Starikovskiy <aystarik@gmail.com>
Cc: Nick Piggin <npiggin@suse.de>,
	Pekka Enberg <penberg@cs.helsinki.fi>,
	Linux Memory Management List <linux-mm@kvack.org>,
	linux-acpi@vger.kernel.org, lenb@kernel.org
Subject: Re: [patch][rfc] acpi: do not use kmem caches
Date: Mon, 1 Dec 2008 12:18:06 -0500	[thread overview]
Message-ID: <20081201171806.GA14074@infradead.org> (raw)
In-Reply-To: <4933F14C.7020200@gmail.com>

On Mon, Dec 01, 2008 at 05:14:36PM +0300, Alexey Starikovskiy wrote:
> Why then you try to delete ACPICA code, which might be just disabled by
> undefining ACPI_USE_LOCAL_CACHE?
> If you do want to go that path, you need to create patch against ACPICA, not
> Linux code.

Sorry dude, but that's not how Linux development works.   Please talk to
some intel OTC folks to get an advice on how it does.

>> Ah OK I misread, that's the cache's freelist... ACPI shouldn't be poking
>> this button inside the slab allocator anyway, honestly. What is it
>> for?
>>   
> And it is not actually used -- you cannot unload ACPI interpreter, and
> this function is called only from there.

Care to remove all this dead code?

>> Is there a reasonable performance or memory win by using kmem cache? If
>> not, then they should not be used
> ACPI is still working in machines with several megabytes of RAM and  
> 100mhz Pentium processors. Do you say we should just not consider them  
> any longer?
> If so, then just delete all ACPICA caches altogether.

As Nick is trying to explain you for a while it's not actually going
to be a performance benefit for these, quite contrary because of how
slab caches waste a lot of memory when only used very lightly or not
at all.

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  parent reply	other threads:[~2008-12-01 17:18 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-12-01  8:31 [patch][rfc] acpi: do not use kmem caches Nick Piggin
2008-12-01 11:18 ` Pekka Enberg
2008-12-01 12:00   ` Nick Piggin
2008-12-01 13:12     ` Alexey Starikovskiy
2008-12-01 13:36       ` Nick Piggin
2008-12-01 14:14         ` Alexey Starikovskiy
2008-12-01 16:32           ` Nick Piggin
2008-12-01 17:18           ` Christoph Hellwig [this message]
2008-12-01 17:32             ` Alexey Starikovskiy
2008-12-01 13:37       ` Pekka Enberg
2008-12-01 14:02         ` Alexey Starikovskiy
2008-12-01 16:14           ` Nick Piggin
2008-12-01 16:45             ` Alexey Starikovskiy
2008-12-01 16:58               ` Nick Piggin
2008-12-01 17:20               ` Moore, Robert
2008-12-01 17:30                 ` Andi Kleen
2008-12-01 17:32                   ` Moore, Robert
2008-12-01 17:20               ` Christoph Hellwig
2008-12-01 17:49                 ` Alexey Starikovskiy
2008-12-01 17:53                 ` Len Brown
2008-12-01 18:10                   ` Nick Piggin
2008-12-31 22:04                     ` Len Brown
2009-01-05  4:14                       ` Nick Piggin
2009-01-05  5:43                         ` Skywing
2009-01-05  6:55                           ` Nick Piggin
2008-12-01 14:32         ` Christoph Lameter
2008-12-01 14:48           ` Alexey Starikovskiy
2008-12-01 16:20             ` Nick Piggin
2008-12-01 17:04               ` Alexey Starikovskiy
2008-12-01 17:12                 ` Nick Piggin
2008-12-01 17:25                   ` Pekka Enberg
2008-12-01 17:32                     ` Pekka Enberg
2008-12-01 17:36                       ` Alexey Starikovskiy
2008-12-01 17:48                         ` Pekka Enberg
2008-12-01 18:09                         ` Christoph Lameter
2008-12-01 17:43                   ` Alexey Starikovskiy
2008-12-01 17:31 ` Len Brown

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