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per-zone and reclaim enhancements for memory controller: modifies vmscan.c for isolate globa/cgroup lru activity 

When using memory controller, there are 2 levels of memory reclaim.
 1. zone memory reclaim because of system/zone memory shortage.
 2. memory cgroup memory reclaim because of hitting limit.

These two can be distinguished by sc->mem_cgroup parameter.
(scan_global_lru() macro)

This patch tries to make memory cgroup reclaim routine avoid affecting
system/zone memory reclaim. This patch inserts if (scan_global_lru()) and
hook to memory_cgroup reclaim support functions.

This patch can be a help for isolating system lru activity and group lru
activity and shows what additional functions are necessary.

 * mem_cgroup_calc_mapped_ratio() ... calculate mapped ratio for cgroup.
 * mem_cgroup_reclaim_imbalance() ... calculate active/inactive balance in
                                        cgroup.
 * mem_cgroup_calc_reclaim_active() ... calculate the number of active pages to
                                be scanned in this priority in mem_cgroup.

 * mem_cgroup_calc_reclaim_inactive() ... calculate the number of inactive pages
                                to be scanned in this priority in mem_cgroup.

 * mem_cgroup_all_unreclaimable() .. checks cgroup's page is all unreclaimable
                                     or not.
 * mem_cgroup_get_reclaim_priority() ...
 * mem_cgroup_note_reclaim_priority() ... record reclaim priority (temporal)
 * mem_cgroup_remember_reclaim_priority()
                             .... record reclaim priority as
                                  zone->prev_priority.
                                  This value is used for calc reclaim_mapped.

[akpm@linux-foundation.org: fix unused var warning]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Paul Menage <menage@google.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
KAMEZAWA Hiroyuki 2008-02-07 00:14:37 -08:00 committed by Linus Torvalds
parent cc38108e1b
commit 1cfb419b39
1 changed files with 201 additions and 131 deletions
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164
mm/vmscan.c
View File

@ -856,6 +856,7 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
__mod_zone_page_state(zone, NR_ACTIVE, -nr_active);
__mod_zone_page_state(zone, NR_INACTIVE,
-(nr_taken - nr_active));
if (scan_global_lru(sc))
zone->pages_scanned += nr_scan;
spin_unlock_irq(&zone->lru_lock);
@ -888,8 +889,9 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
if (current_is_kswapd()) {
__count_zone_vm_events(PGSCAN_KSWAPD, zone, nr_scan);
__count_vm_events(KSWAPD_STEAL, nr_freed);
} else
} else if (scan_global_lru(sc))
__count_zone_vm_events(PGSCAN_DIRECT, zone, nr_scan);
__count_zone_vm_events(PGSTEAL, zone, nr_freed);
if (nr_taken == 0)
@ -943,49 +945,31 @@ static inline int zone_is_near_oom(struct zone *zone)
}
/*
* This moves pages from the active list to the inactive list.
*
* We move them the other way if the page is referenced by one or more
* processes, from rmap.
*
* If the pages are mostly unmapped, the processing is fast and it is
* appropriate to hold zone->lru_lock across the whole operation. But if
* the pages are mapped, the processing is slow (page_referenced()) so we
* should drop zone->lru_lock around each page. It's impossible to balance
* this, so instead we remove the pages from the LRU while processing them.
* It is safe to rely on PG_active against the non-LRU pages in here because
* nobody will play with that bit on a non-LRU page.
*
* The downside is that we have to touch page->_count against each page.
* But we had to alter page->flags anyway.
* Determine we should try to reclaim mapped pages.
* This is called only when sc->mem_cgroup is NULL.
*/
static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
struct scan_control *sc, int priority)
static int calc_reclaim_mapped(struct scan_control *sc, struct zone *zone,
int priority)
{
unsigned long pgmoved;
int pgdeactivate = 0;
unsigned long pgscanned;
LIST_HEAD(l_hold); /* The pages which were snipped off */
LIST_HEAD(l_inactive); /* Pages to go onto the inactive_list */
LIST_HEAD(l_active); /* Pages to go onto the active_list */
struct page *page;
struct pagevec pvec;
int reclaim_mapped = 0;
if (sc->may_swap) {
long mapped_ratio;
long distress;
long swap_tendency;
long imbalance;
int reclaim_mapped = 0;
int prev_priority;
if (zone_is_near_oom(zone))
goto force_reclaim_mapped;
if (scan_global_lru(sc) && zone_is_near_oom(zone))
return 1;
/*
* `distress' is a measure of how much trouble we're having
* reclaiming pages. 0 -> no problems. 100 -> great trouble.
*/
distress = 100 >> min(zone->prev_priority, priority);
if (scan_global_lru(sc))
prev_priority = zone->prev_priority;
else
prev_priority = mem_cgroup_get_reclaim_priority(sc->mem_cgroup);
distress = 100 >> min(prev_priority, priority);
/*
* The point of this algorithm is to decide when to start
@ -993,9 +977,12 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
* how much memory
* is mapped.
*/
if (scan_global_lru(sc))
mapped_ratio = ((global_page_state(NR_FILE_MAPPED) +
global_page_state(NR_ANON_PAGES)) * 100) /
vm_total_pages;
else
mapped_ratio = mem_cgroup_calc_mapped_ratio(sc->mem_cgroup);
/*
* Now decide how much we really want to unmap some pages. The
@ -1023,8 +1010,11 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
* Avoid div by zero with nr_inactive+1, and max resulting
* value is vm_total_pages.
*/
if (scan_global_lru(sc)) {
imbalance = zone_page_state(zone, NR_ACTIVE);
imbalance /= zone_page_state(zone, NR_INACTIVE) + 1;
} else
imbalance = mem_cgroup_reclaim_imbalance(sc->mem_cgroup);
/*
* Reduce the effect of imbalance if swappiness is low,
@ -1056,16 +1046,58 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
* memory onto the inactive list.
*/
if (swap_tendency >= 100)
force_reclaim_mapped:
reclaim_mapped = 1;
}
return reclaim_mapped;
}
/*
* This moves pages from the active list to the inactive list.
*
* We move them the other way if the page is referenced by one or more
* processes, from rmap.
*
* If the pages are mostly unmapped, the processing is fast and it is
* appropriate to hold zone->lru_lock across the whole operation. But if
* the pages are mapped, the processing is slow (page_referenced()) so we
* should drop zone->lru_lock around each page. It's impossible to balance
* this, so instead we remove the pages from the LRU while processing them.
* It is safe to rely on PG_active against the non-LRU pages in here because
* nobody will play with that bit on a non-LRU page.
*
* The downside is that we have to touch page->_count against each page.
* But we had to alter page->flags anyway.
*/
static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
struct scan_control *sc, int priority)
{
unsigned long pgmoved;
int pgdeactivate = 0;
unsigned long pgscanned;
LIST_HEAD(l_hold); /* The pages which were snipped off */
LIST_HEAD(l_inactive); /* Pages to go onto the inactive_list */
LIST_HEAD(l_active); /* Pages to go onto the active_list */
struct page *page;
struct pagevec pvec;
int reclaim_mapped = 0;
if (sc->may_swap)
reclaim_mapped = calc_reclaim_mapped(sc, zone, priority);
lru_add_drain();
spin_lock_irq(&zone->lru_lock);
pgmoved = sc->isolate_pages(nr_pages, &l_hold, &pgscanned, sc->order,
ISOLATE_ACTIVE, zone,
sc->mem_cgroup, 1);
/*
* zone->pages_scanned is used for detect zone's oom
* mem_cgroup remembers nr_scan by itself.
*/
if (scan_global_lru(sc))
zone->pages_scanned += pgscanned;
__mod_zone_page_state(zone, NR_ACTIVE, -pgmoved);
spin_unlock_irq(&zone->lru_lock);
@ -1155,18 +1187,14 @@ static unsigned long shrink_zone(int priority, struct zone *zone,
unsigned long nr_to_scan;
unsigned long nr_reclaimed = 0;
if (scan_global_lru(sc)) {
/*
* Add one to `nr_to_scan' just to make sure that the kernel will
* slowly sift through the active list.
* Add one to nr_to_scan just to make sure that the kernel
* will slowly sift through the active list.
*/
zone->nr_scan_active +=
(zone_page_state(zone, NR_ACTIVE) >> priority) + 1;
nr_active = zone->nr_scan_active;
if (nr_active >= sc->swap_cluster_max)
zone->nr_scan_active = 0;
else
nr_active = 0;
zone->nr_scan_inactive +=
(zone_page_state(zone, NR_INACTIVE) >> priority) + 1;
nr_inactive = zone->nr_scan_inactive;
@ -1175,6 +1203,24 @@ static unsigned long shrink_zone(int priority, struct zone *zone,
else
nr_inactive = 0;
if (nr_active >= sc->swap_cluster_max)
zone->nr_scan_active = 0;
else
nr_active = 0;
} else {
/*
* This reclaim occurs not because zone memory shortage but
* because memory controller hits its limit.
* Then, don't modify zone reclaim related data.
*/
nr_active = mem_cgroup_calc_reclaim_active(sc->mem_cgroup,
zone, priority);
nr_inactive = mem_cgroup_calc_reclaim_inactive(sc->mem_cgroup,
zone, priority);
}
while (nr_active || nr_inactive) {
if (nr_active) {
nr_to_scan = min(nr_active,
@ -1218,25 +1264,39 @@ static unsigned long shrink_zones(int priority, struct zone **zones,
unsigned long nr_reclaimed = 0;
int i;
sc->all_unreclaimable = 1;
for (i = 0; zones[i] != NULL; i++) {
struct zone *zone = zones[i];
if (!populated_zone(zone))
continue;
/*
* Take care memory controller reclaiming has small influence
* to global LRU.
*/
if (scan_global_lru(sc)) {
if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
continue;
note_zone_scanning_priority(zone, priority);
if (zone_is_all_unreclaimable(zone) && priority != DEF_PRIORITY)
if (zone_is_all_unreclaimable(zone) &&
priority != DEF_PRIORITY)
continue; /* Let kswapd poll it */
sc->all_unreclaimable = 0;
} else {
/*
* Ignore cpuset limitation here. We just want to reduce
* # of used pages by us regardless of memory shortage.
*/
sc->all_unreclaimable = 0;
mem_cgroup_note_reclaim_priority(sc->mem_cgroup,
priority);
}
nr_reclaimed += shrink_zone(priority, zone, sc);
}
return nr_reclaimed;
}
@ -1264,8 +1324,12 @@ static unsigned long do_try_to_free_pages(struct zone **zones, gfp_t gfp_mask,
unsigned long lru_pages = 0;
int i;
if (scan_global_lru(sc))
count_vm_event(ALLOCSTALL);
/*
* mem_cgroup will not do shrink_slab.
*/
if (scan_global_lru(sc)) {
for (i = 0; zones[i] != NULL; i++) {
struct zone *zone = zones[i];
@ -1275,6 +1339,7 @@ static unsigned long do_try_to_free_pages(struct zone **zones, gfp_t gfp_mask,
lru_pages += zone_page_state(zone, NR_ACTIVE)
+ zone_page_state(zone, NR_INACTIVE);
}
}
for (priority = DEF_PRIORITY; priority >= 0; priority--) {
sc->nr_scanned = 0;
@ -1330,6 +1395,8 @@ out:
*/
if (priority < 0)
priority = 0;
if (scan_global_lru(sc)) {
for (i = 0; zones[i] != NULL; i++) {
struct zone *zone = zones[i];
@ -1338,6 +1405,9 @@ out:
zone->prev_priority = priority;
}
} else
mem_cgroup_record_reclaim_priority(sc->mem_cgroup, priority);
return ret;
}