Re: Large slab cache in 2.6.1

Nick Piggin
2004-02-22T05:37:55Z

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Mike Fedyk wrote:

> Nick Piggin wrote:
>
>>
>>
>> Nick Piggin wrote:
>>
>>>
>>> Actually I think the previous shrink_slab formula factors
>>> out to the right thing anyway, so nevermind this patch :P
>>>
>>>
>>
>> Although, nr_used_zone_pages probably shouldn't be counting
>> highmem zones, which might be our problem.
>
>
> What is the kernel parameter to disable highmem? I saw nohighio, but
> that's not it...
>

Not sure. That defeats the purpose of trying to get your setup
working nicely though ;)

Can you upgrade to 2.6.3-mm2? It would be ideal if you could
test this patch against that kernel due to the other VM changes.

Chris, could you test this too please? Thanks.

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linux-2.6-npiggin/include/linux/mm.h | 2 +-
linux-2.6-npiggin/mm/page_alloc.c | 13 +++++++++----
linux-2.6-npiggin/mm/vmscan.c | 22 ++++++++++++----------
3 files changed, 22 insertions(+), 15 deletions(-)

diff -puN mm/vmscan.c~vm-shrink-slab-lowmem mm/vmscan.c
--- linux-2.6/mm/vmscan.c~vm-shrink-slab-lowmem 2004-02-22 16:35:06.000000000 +1100
+++ linux-2.6-npiggin/mm/vmscan.c 2004-02-22 16:35:06.000000000 +1100
@@ -145,7 +145,7 @@ static int shrink_slab(unsigned long sca
if (down_trylock(&shrinker_sem))
return 0;

- pages = nr_used_zone_pages();
+ pages = nr_lowmem_lru_pages();
list_for_each_entry(shrinker, &shrinker_list, list) {
unsigned long long delta;

@@ -857,7 +857,8 @@ shrink_zone(struct zone *zone, unsigned
*/
static int
shrink_caches(struct zone **zones, int priority, int *total_scanned,
- int gfp_mask, int nr_pages, struct page_state *ps)
+ int *lowmem_scanned, int gfp_mask, int nr_pages,
+ struct page_state *ps)
{
int ret = 0;
int i;
@@ -875,7 +876,10 @@ shrink_caches(struct zone **zones, int p

ret += shrink_zone(zone, gfp_mask,
to_reclaim, &nr_scanned, ps, priority);
+
*total_scanned += nr_scanned;
+ if (i < ZONE_HIGHMEM)
+ *lowmem_scanned += nr_scanned;
if (ret >= nr_pages)
break;
}
@@ -915,19 +919,17 @@ int try_to_free_pages(struct zone **zone
zones[i]->temp_priority = DEF_PRIORITY;

for (priority = DEF_PRIORITY; priority >= 0; priority--) {
- int total_scanned = 0;
+ int total_scanned = 0, lowmem_scanned = 0;
struct page_state ps;

get_page_state(&ps);
nr_reclaimed += shrink_caches(zones, priority, &total_scanned,
- gfp_mask, nr_pages, &ps);
+ &lowmem_scanned, gfp_mask, nr_pages, &ps);

- if (zones[0] - zones[0]->zone_pgdat->node_zones < ZONE_HIGHMEM) {
- shrink_slab(total_scanned, gfp_mask);
- if (reclaim_state) {
- nr_reclaimed += reclaim_state->reclaimed_slab;
- reclaim_state->reclaimed_slab = 0;
- }
+ shrink_slab(lowmem_scanned, gfp_mask);
+ if (reclaim_state) {
+ nr_reclaimed += reclaim_state->reclaimed_slab;
+ reclaim_state->reclaimed_slab = 0;
}

if (nr_reclaimed >= nr_pages) {
diff -puN mm/page_alloc.c~vm-shrink-slab-lowmem mm/page_alloc.c
--- linux-2.6/mm/page_alloc.c~vm-shrink-slab-lowmem 2004-02-22 16:35:06.000000000 +1100
+++ linux-2.6-npiggin/mm/page_alloc.c 2004-02-22 16:35:06.000000000 +1100
@@ -772,13 +772,18 @@ unsigned int nr_free_pages(void)

EXPORT_SYMBOL(nr_free_pages);

-unsigned int nr_used_zone_pages(void)
+unsigned int nr_lowmem_lru_pages(void)
{
+ pg_data_t *pgdat;
unsigned int pages = 0;
- struct zone *zone;

- for_each_zone(zone)
- pages += zone->nr_active + zone->nr_inactive;
+ for_each_pgdat(pgdat) {
+ int i;
+ for (i = 0; i < ZONE_HIGHMEM; i++) {
+ struct zone *zone = pgdat->node_zones + i;
+ pages += zone->nr_active + zone->nr_inactive;
+ }
+ }

return pages;
}
diff -puN include/linux/mm.h~vm-shrink-slab-lowmem include/linux/mm.h
--- linux-2.6/include/linux/mm.h~vm-shrink-slab-lowmem 2004-02-22 16:35:06.000000000 +1100
+++ linux-2.6-npiggin/include/linux/mm.h 2004-02-22 16:35:06.000000000 +1100
@@ -625,7 +625,7 @@ static inline struct vm_area_struct * fi

extern struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr);

-extern unsigned int nr_used_zone_pages(void);
+extern unsigned int nr_lowmem_lru_pages(void);

extern struct page * vmalloc_to_page(void *addr);
extern struct page * follow_page(struct mm_struct *mm, unsigned long address,

_