diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memcontrol.c | 43 | ||||
| -rw-r--r-- | mm/migrate.c | 13 |
2 files changed, 53 insertions, 3 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 3270ce7375d..128f45c16fa 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -492,6 +492,49 @@ void mem_cgroup_uncharge(struct page_cgroup *pc) } } } +/* + * Returns non-zero if a page (under migration) has valid page_cgroup member. + * Refcnt of page_cgroup is incremented. + */ + +int mem_cgroup_prepare_migration(struct page *page) +{ + struct page_cgroup *pc; + int ret = 0; + lock_page_cgroup(page); + pc = page_get_page_cgroup(page); + if (pc && atomic_inc_not_zero(&pc->ref_cnt)) + ret = 1; + unlock_page_cgroup(page); + return ret; +} + +void mem_cgroup_end_migration(struct page *page) +{ + struct page_cgroup *pc = page_get_page_cgroup(page); + mem_cgroup_uncharge(pc); +} +/* + * We know both *page* and *newpage* are now not-on-LRU and Pg_locked. + * And no race with uncharge() routines because page_cgroup for *page* + * has extra one reference by mem_cgroup_prepare_migration. + */ + +void mem_cgroup_page_migration(struct page *page, struct page *newpage) +{ + struct page_cgroup *pc; +retry: + pc = page_get_page_cgroup(page); + if (!pc) + return; + if (clear_page_cgroup(page, pc) != pc) + goto retry; + pc->page = newpage; + lock_page_cgroup(newpage); + page_assign_page_cgroup(newpage, pc); + unlock_page_cgroup(newpage); + return; +} int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp) { diff --git a/mm/migrate.c b/mm/migrate.c index 76379414469..a73504ff5ab 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -593,9 +593,10 @@ static int move_to_new_page(struct page *newpage, struct page *page) else rc = fallback_migrate_page(mapping, newpage, page); - if (!rc) + if (!rc) { + mem_cgroup_page_migration(page, newpage); remove_migration_ptes(page, newpage); - else + } else newpage->mapping = NULL; unlock_page(newpage); @@ -614,6 +615,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, int *result = NULL; struct page *newpage = get_new_page(page, private, &result); int rcu_locked = 0; + int charge = 0; if (!newpage) return -ENOMEM; @@ -673,14 +675,19 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, goto rcu_unlock; } + charge = mem_cgroup_prepare_migration(page); /* Establish migration ptes or remove ptes */ try_to_unmap(page, 1); if (!page_mapped(page)) rc = move_to_new_page(newpage, page); - if (rc) + if (rc) { remove_migration_ptes(page, page); + if (charge) + mem_cgroup_end_migration(page); + } else if (charge) + mem_cgroup_end_migration(newpage); rcu_unlock: if (rcu_locked) rcu_read_unlock(); |