At this point, I'm not sure this is a fix for https://bugzilla.kernel.org/show_bug.cgi?id=30432. The behavior seems very similar to SwapCache case and this is a possible bug and this patch can be a fix. Nishimura-san, how do you think ? But I'm not sure how to test this....please review. = fs/fuse/dev.c::fuse_try_move_page() does (1) remove a page from page cache by ->steal() (2) re-add the page to page cache (3) link the page to LRU if it was _not_ on LRU at (1) This implies the page can be _on_ LRU when add_to_page_cache_locked() is called. So, the page is added to a memory cgroup while it's on LRU. This is the same behavior as SwapCache, 'newly charged pages may be on LRU' and needs special care as - remove page from old memcg's LRU before overwrite pc->mem_cgroup. - add page to new memcg's LRU after overwrite pc->mem_cgroup. So, reusing SwapCache code with renaming for fix. Note: a page on pagevec(LRU). If a page is not PageLRU(page) but on pagevec(LRU), it may be added to LRU while we overwrite page->mapping. But in that case, PCG_USED bit of the page_cgroup is not set and the page_cgroup will not be added to wrong memcg's LRU. So, this patch's logic will work fine. (It has been tested with SwapCache.) Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> --- mm/memcontrol.c | 42 +++++++++++++++++++++++------------------- 1 file changed, 23 insertions(+), 19 deletions(-) Index: mmotm-0303/mm/memcontrol.c =================================================================== --- mmotm-0303.orig/mm/memcontrol.c +++ mmotm-0303/mm/memcontrol.c @@ -926,13 +926,12 @@ void mem_cgroup_add_lru_list(struct page } /* - * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to - * lru because the page may.be reused after it's fully uncharged (because of - * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge - * it again. This function is only used to charge SwapCache. It's done under - * lock_page and expected that zone->lru_lock is never held. + * At handling SwapCache and other FUSE stuff, pc->mem_cgroup may be changed + * while it's linked to lru because the page may be reused after it's fully + * uncharged. To handle that, unlink page_cgroup from LRU when charge it again. + * It's done under lock_page and expected that zone->lru_lock isnever held. */ -static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page) +static void mem_cgroup_lru_del_before_commit(struct page *page) { unsigned long flags; struct zone *zone = page_zone(page); @@ -948,7 +947,7 @@ static void mem_cgroup_lru_del_before_co spin_unlock_irqrestore(&zone->lru_lock, flags); } -static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page) +static void mem_cgroup_lru_add_after_commit(struct page *page) { unsigned long flags; struct zone *zone = page_zone(page); @@ -2428,7 +2427,7 @@ int mem_cgroup_newpage_charge(struct pag } static void -__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, +__mem_cgroup_commit_charge_lrucare(struct page *page, struct mem_cgroup *ptr, enum charge_type ctype); int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, @@ -2468,17 +2467,22 @@ int mem_cgroup_cache_charge(struct page if (unlikely(!mm)) mm = &init_mm; - if (page_is_file_cache(page)) - return mem_cgroup_charge_common(page, mm, gfp_mask, + if (page_is_file_cache(page) && !PageLRU(page)) { + ret = mem_cgroup_charge_common(page, mm, gfp_mask, MEM_CGROUP_CHARGE_TYPE_CACHE); - - /* shmem */ - if (PageSwapCache(page)) { + } else if (page_is_file_cache(page)) { + struct mem_cgroup *mem; + /* Page on LRU should be moved to the _new_ LRU */ + ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, &mem, true); + if (!ret) + __mem_cgroup_commit_charge_lrucare(page, mem, + MEM_CGROUP_CHARGE_TYPE_CACHE); + } else if (PageSwapCache(page)) { struct mem_cgroup *mem; - ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem); + if (!ret) - __mem_cgroup_commit_charge_swapin(page, mem, + __mem_cgroup_commit_charge_lrucare(page, mem, MEM_CGROUP_CHARGE_TYPE_SHMEM); } else ret = mem_cgroup_charge_common(page, mm, gfp_mask, @@ -2529,7 +2533,7 @@ charge_cur_mm: } static void -__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, +__mem_cgroup_commit_charge_lrucare(struct page *page, struct mem_cgroup *ptr, enum charge_type ctype) { struct page_cgroup *pc; @@ -2540,9 +2544,9 @@ __mem_cgroup_commit_charge_swapin(struct return; cgroup_exclude_rmdir(&ptr->css); pc = lookup_page_cgroup(page); - mem_cgroup_lru_del_before_commit_swapcache(page); + mem_cgroup_lru_del_before_commit(page); __mem_cgroup_commit_charge(ptr, page, 1, pc, ctype); - mem_cgroup_lru_add_after_commit_swapcache(page); + mem_cgroup_lru_add_after_commit(page); /* * Now swap is on-memory. This means this page may be * counted both as mem and swap....double count. @@ -2580,7 +2584,7 @@ __mem_cgroup_commit_charge_swapin(struct void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr) { - __mem_cgroup_commit_charge_swapin(page, ptr, + __mem_cgroup_commit_charge_lrucare(page, ptr, MEM_CGROUP_CHARGE_TYPE_MAPPED); } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>