linux-kernel - [PATCH] x86: have set_memory_array

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Date:	Fri, 22 Aug 2008 01:02:20 +0200
From:	Rene Herman <rene.herman@...access.nl>
To:	Ingo Molnar <mingo@...e.hu>
CC:	Venki Pallipadi <venkatesh.pallipadi@...el.com>,
	Dave Airlie <airlied@...il.com>,
	"Li, Shaohua" <shaohua.li@...el.com>,
	Yinghai Lu <yhlu.kernel@...il.com>,
	Andreas Herrmann <andreas.herrmann3@....com>,
	Arjan van de Ven <arjan@...radead.org>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	"Siddha, Suresh B" <suresh.b.siddha@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	Dave Jones <davej@...emonkey.org.uk>
Subject: [PATCH] x86: have set_memory_array_{uc,wb} coalesce memtypes.

On 21-08-08 19:15, Rene Herman wrote:

> On 21-08-08 14:06, Ingo Molnar wrote:

>> Would be nice to test tip/master - it has both that patch included and 
>> the latest pageattr-array API (with enablement in AGP drivers) 
>> patchset, done by Shaohua Li, based on Dave's original patch.
> 
> That patch by itself doesn't help any -- the new set_memory_array_uc() 
> still calls reserve_memtype() for each single page in the array. To 
> help, it needs to coalesce adjacent entries, which is itself easy to do 
> were it not for the need to keep the list of reserved (base,end) pairs 
> around for free_memtype() time (and halfway fail time).

Actually, might as well simply reconstruct the memtype list at free time 
I guess. How is this for a coalescing version of the array functions?

NOTE: I am posting this because I'm going to bed but haven't stared 
comfortably long at this and might be buggy. Compiles, boots and 
provides me with:

root@...e4:~# wc -l /debug/x86/pat_memtype_list
53 /debug/x86/pat_memtype_list

otherwise (down from 16384+).

<snore>

Rene.

View attachment "0001-x86-have-set_memory_array_-uc-wb-coalesce-memtypes.patch" of type "text/plain" (2237 bytes)