From: Johannes Weiner <hannes@xxxxxxxxxxx> Subject: mm: memcontrol: drop unused try/commit/cancel charge API There are no more users. RIP in peace. [arnd@xxxxxxxx: fix an unused-function warning] Link: http://lkml.kernel.org/r/20200528095640.151454-1-arnd@xxxxxxxx Link: http://lkml.kernel.org/r/20200508183105.225460-14-hannes@xxxxxxxxxxx Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: "Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Roman Gushchin <guro@xxxxxx> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx> Cc: Balbir Singh <bsingharora@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/memcontrol.h | 36 --------- mm/memcontrol.c | 128 ++++------------------------------- 2 files changed, 17 insertions(+), 147 deletions(-) --- a/include/linux/memcontrol.h~mm-memcontrol-drop-unused-try-commit-cancel-charge-api +++ a/include/linux/memcontrol.h @@ -355,14 +355,6 @@ static inline unsigned long mem_cgroup_p enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root, struct mem_cgroup *memcg); -int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm, - gfp_t gfp_mask, struct mem_cgroup **memcgp); -int mem_cgroup_try_charge_delay(struct page *page, struct mm_struct *mm, - gfp_t gfp_mask, struct mem_cgroup **memcgp); -void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg, - bool lrucare); -void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg); - int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask, bool lrucare); @@ -846,34 +838,6 @@ static inline enum mem_cgroup_protection return MEMCG_PROT_NONE; } -static inline int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm, - gfp_t gfp_mask, - struct mem_cgroup **memcgp) -{ - *memcgp = NULL; - return 0; -} - -static inline int mem_cgroup_try_charge_delay(struct page *page, - struct mm_struct *mm, - gfp_t gfp_mask, - struct mem_cgroup **memcgp) -{ - *memcgp = NULL; - return 0; -} - -static inline void mem_cgroup_commit_charge(struct page *page, - struct mem_cgroup *memcg, - bool lrucare) -{ -} - -static inline void mem_cgroup_cancel_charge(struct page *page, - struct mem_cgroup *memcg) -{ -} - static inline int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask, bool lrucare) { --- a/mm/memcontrol.c~mm-memcontrol-drop-unused-try-commit-cancel-charge-api +++ a/mm/memcontrol.c @@ -2641,6 +2641,7 @@ done_restock: return 0; } +#if defined(CONFIG_MEMCG_KMEM) || defined(CONFIG_MMU) static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages) { if (mem_cgroup_is_root(memcg)) @@ -2652,6 +2653,7 @@ static void cancel_charge(struct mem_cgr css_put_many(&memcg->css, nr_pages); } +#endif static void lock_page_lru(struct page *page, int *isolated) { @@ -6499,29 +6501,26 @@ out: } /** - * mem_cgroup_try_charge - try charging a page + * mem_cgroup_charge - charge a newly allocated page to a cgroup * @page: page to charge * @mm: mm context of the victim * @gfp_mask: reclaim mode - * @memcgp: charged memcg return + * @lrucare: page might be on the LRU already * * Try to charge @page to the memcg that @mm belongs to, reclaiming * pages according to @gfp_mask if necessary. * - * Returns 0 on success, with *@memcgp pointing to the charged memcg. - * Otherwise, an error code is returned. - * - * After page->mapping has been set up, the caller must finalize the - * charge with mem_cgroup_commit_charge(). Or abort the transaction - * with mem_cgroup_cancel_charge() in case page instantiation fails. + * Returns 0 on success. Otherwise, an error code is returned. */ -int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm, - gfp_t gfp_mask, struct mem_cgroup **memcgp) +int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask, + bool lrucare) { unsigned int nr_pages = hpage_nr_pages(page); struct mem_cgroup *memcg = NULL; int ret = 0; + VM_BUG_ON_PAGE(PageLRU(page) && !lrucare, page); + if (mem_cgroup_disabled()) goto out; @@ -6553,56 +6552,8 @@ int mem_cgroup_try_charge(struct page *p memcg = get_mem_cgroup_from_mm(mm); ret = try_charge(memcg, gfp_mask, nr_pages); - - css_put(&memcg->css); -out: - *memcgp = memcg; - return ret; -} - -int mem_cgroup_try_charge_delay(struct page *page, struct mm_struct *mm, - gfp_t gfp_mask, struct mem_cgroup **memcgp) -{ - int ret; - - ret = mem_cgroup_try_charge(page, mm, gfp_mask, memcgp); - if (*memcgp) - cgroup_throttle_swaprate(page, gfp_mask); - return ret; -} - -/** - * mem_cgroup_commit_charge - commit a page charge - * @page: page to charge - * @memcg: memcg to charge the page to - * @lrucare: page might be on LRU already - * - * Finalize a charge transaction started by mem_cgroup_try_charge(), - * after page->mapping has been set up. This must happen atomically - * as part of the page instantiation, i.e. under the page table lock - * for anonymous pages, under the page lock for page and swap cache. - * - * In addition, the page must not be on the LRU during the commit, to - * prevent racing with task migration. If it might be, use @lrucare. - * - * Use mem_cgroup_cancel_charge() to cancel the transaction instead. - */ -void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg, - bool lrucare) -{ - unsigned int nr_pages = hpage_nr_pages(page); - - VM_BUG_ON_PAGE(PageLRU(page) && !lrucare, page); - - if (mem_cgroup_disabled()) - return; - /* - * Swap faults will attempt to charge the same page multiple - * times. But reuse_swap_page() might have removed the page - * from swapcache already, so we can't check PageSwapCache(). - */ - if (!memcg) - return; + if (ret) + goto out_put; commit_charge(page, memcg, lrucare); @@ -6620,55 +6571,11 @@ void mem_cgroup_commit_charge(struct pag */ mem_cgroup_uncharge_swap(entry, nr_pages); } -} -/** - * mem_cgroup_cancel_charge - cancel a page charge - * @page: page to charge - * @memcg: memcg to charge the page to - * - * Cancel a charge transaction started by mem_cgroup_try_charge(). - */ -void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg) -{ - unsigned int nr_pages = hpage_nr_pages(page); - - if (mem_cgroup_disabled()) - return; - /* - * Swap faults will attempt to charge the same page multiple - * times. But reuse_swap_page() might have removed the page - * from swapcache already, so we can't check PageSwapCache(). - */ - if (!memcg) - return; - - cancel_charge(memcg, nr_pages); -} - -/** - * mem_cgroup_charge - charge a newly allocated page to a cgroup - * @page: page to charge - * @mm: mm context of the victim - * @gfp_mask: reclaim mode - * @lrucare: page might be on the LRU already - * - * Try to charge @page to the memcg that @mm belongs to, reclaiming - * pages according to @gfp_mask if necessary. - * - * Returns 0 on success. Otherwise, an error code is returned. - */ -int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask, - bool lrucare) -{ - struct mem_cgroup *memcg; - int ret; - - ret = mem_cgroup_try_charge(page, mm, gfp_mask, &memcg); - if (ret) - return ret; - mem_cgroup_commit_charge(page, memcg, lrucare); - return 0; +out_put: + css_put(&memcg->css); +out: + return ret; } struct uncharge_gather { @@ -6773,8 +6680,7 @@ static void uncharge_list(struct list_he * mem_cgroup_uncharge - uncharge a page * @page: page to uncharge * - * Uncharge a page previously charged with mem_cgroup_try_charge() and - * mem_cgroup_commit_charge(). + * Uncharge a page previously charged with mem_cgroup_charge(). */ void mem_cgroup_uncharge(struct page *page) { @@ -6797,7 +6703,7 @@ void mem_cgroup_uncharge(struct page *pa * @page_list: list of pages to uncharge * * Uncharge a list of pages previously charged with - * mem_cgroup_try_charge() and mem_cgroup_commit_charge(). + * mem_cgroup_charge(). */ void mem_cgroup_uncharge_list(struct list_head *page_list) { _
