Re: [patch 05/19] split LRU lists into anon & file sets

KOSAKI Motohiro
2008-01-30T03:29:04Z

Hi Rik, Lee

I tested new hackbench on rvr split LRU patch.
http://people.redhat.com/mingo/cfs-scheduler/tools/hackbench.c

method of test

(1) $ ./hackbench 150 process 1000
(2) # sync; echo 3 > /proc/sys/vm/drop_caches
$ dd if=tmp10G of=/dev/null
$ ./hackbench 150 process 1000

test machine
CPU: Itanium2 x4 (logical 8cpu)
MEM: 8GB

A. vanilla 2.6.24-rc8-mm1
(1) 127.540
(2) 727.548

B. 2.6.24-rc8-mm1 + split-lru-patch-series
(1) 92.730
(2) 758.369

comment:
(1) active/inactive anon ratio improve performance significant.
(2) incorrect page activation reduce performance.

I investigate reason and found reason is [05/19] change.
I tested a bit porton reverted split-lru-patch-series again.

C. 2.6.24-rc8-mm1 + split-lru-patch-series + my-revert-patch
(1) 83.014
(2) 717.009

Of course, We need reintroduce this portion after new page LRU
(aka LRU for used only page).
but now is too early.

I hope this patch series merge to -mm ASAP.
therefore, I hope remove any corner case regression.

Thanks!

- kosaki

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>

---
mm/vmscan.c | 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)

Index: b/mm/vmscan.c
===================================================================
--- a/mm/vmscan.c 2008-01-29 15:59:17.000000000 +0900
+++ b/mm/vmscan.c 2008-01-30 11:53:42.000000000 +0900
@@ -247,6 +247,27 @@
return ret;
}

+/* Called without lock on whether page is mapped, so answer is unstable */
+static inline int page_mapping_inuse(struct page *page)
+{
+ struct address_space *mapping;
+
+ /* Page is in somebody's page tables. */
+ if (page_mapped(page))
+ return 1;
+
+ /* Be more reluctant to reclaim swapcache than pagecache */
+ if (PageSwapCache(page))
+ return 1;
+
+ mapping = page_mapping(page);
+ if (!mapping)
+ return 0;
+
+ /* File is mmap'd by somebody? */
+ return mapping_mapped(mapping);
+}
+
static inline int is_page_cache_freeable(struct page *page)
{
return page_count(page) - !!PagePrivate(page) == 2;
@@ -515,7 +536,8 @@

referenced = page_referenced(page, 1, sc->mem_cgroup);
/* In active use or really unfreeable? Activate it. */
- if (sc->order <= PAGE_ALLOC_COSTLY_ORDER && referenced)
+ if (sc->order <= PAGE_ALLOC_COSTLY_ORDER &&
+ referenced && page_mapping_inuse(page))
goto activate_locked;

#ifdef CONFIG_SWAP
@@ -550,6 +572,8 @@
}

if (PageDirty(page)) {
+ if (sc->order <= PAGE_ALLOC_COSTLY_ORDER && referenced)
+ goto keep_locked;
if (!may_enter_fs) {
sc->nr_io_pages++;
goto keep_locked;