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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@7ixe4:~# wc -l /debug/x86/pat_memtype_list
53 /debug/x86/pat_memtype_list

otherwise (down from 16384+).

<snore>

Rene.
From b5dc6e481b38cf4e7792bcb9a8f5dd9aab0e5590 Mon Sep 17 00:00:00 2001
From: Rene Herman <rene.herman@gmail.com>
Date: Fri, 22 Aug 2008 00:56:00 +0200
Subject: [PATCH] x86: have set_memory_array_{uc,wb} coalesce memtypes.

---
arch/x86/mm/pageattr.c | 38 ++++++++++++++++++++++++++++++++------
1 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index d49e4db..a2a497a 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -942,21 +942,38 @@ EXPORT_SYMBOL(set_memory_uc);

int set_memory_array_uc(unsigned long *addr, int addrinarray)
{
+ unsigned long start;
+ unsigned long end;
int i;
/*
* for now UC MINUS. see comments in ioremap_nocache()
*/
for (i = 0; i < addrinarray; i++) {
- if (reserve_memtype(__pa(addr[i]), __pa(addr[i]) + PAGE_SIZE,
- _PAGE_CACHE_UC_MINUS, NULL))
+ start = __pa(addr[i]);
+ for (end = start + PAGE_SIZE; i < addrinarray - 1; end += PAGE_SIZE) {
+ if (end != __pa(addr[i + 1]))
+ break;
+ i++;
+ }
+ if (reserve_memtype(start, end, _PAGE_CACHE_UC_MINUS, NULL))
goto out;
}

return change_page_attr_set(addr, addrinarray,
__pgprot(_PAGE_CACHE_UC_MINUS), 1);
out:
- while (--i >= 0)
- free_memtype(__pa(addr[i]), __pa(addr[i]) + PAGE_SIZE);
+ for (i = 0; i < addrinarray; i++) {
+ unsigned long tmp = __pa(addr[i]);
+
+ if (tmp == start)
+ break;
+ for (end = start + PAGE_SIZE; i < addrinarray - 1; end += PAGE_SIZE) {
+ if (end != __pa(addr[i + 1]))
+ break;
+ i++;
+ }
+ free_memtype(tmp, end);
+ }
return -EINVAL;
}
EXPORT_SYMBOL(set_memory_array_uc);
@@ -997,9 +1014,18 @@ EXPORT_SYMBOL(set_memory_wb);
int set_memory_array_wb(unsigned long *addr, int addrinarray)
{
int i;
- for (i = 0; i < addrinarray; i++)
- free_memtype(__pa(addr[i]), __pa(addr[i]) + PAGE_SIZE);

+ for (i = 0; i < addrinarray; i++) {
+ unsigned long start = __pa(addr[i]);
+ unsigned long end;
+
+ for (end = start + PAGE_SIZE; i < addrinarray - 1; end += PAGE_SIZE) {
+ if (end != __pa(addr[i + 1]))
+ break;
+ i++;
+ }
+ free_memtype(start, end);
+ }
return change_page_attr_clear(addr, addrinarray,
__pgprot(_PAGE_CACHE_MASK), 1);
}
--
1.5.5
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