| Message ID | 20241024065712.1274481-3-shakeel.butt@linux.dev (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | memcg-v1: fully deprecate charge moving | expand |
On Wed 23-10-24 23:57:11, Shakeel Butt wrote: > The memcg-v1 charge move feature has been deprecated completely and > let's remove the relevant code as well. > > Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Michal Hocko <mhocko@suse.com> > --- > include/linux/memcontrol.h | 5 - > mm/memcontrol-v1.c | 864 ------------------------------------- > mm/memcontrol-v1.h | 6 - > mm/memcontrol.c | 9 - > 4 files changed, 884 deletions(-) > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index 524006313b0d..798db70b0a30 100644 > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -299,11 +299,6 @@ struct mem_cgroup { > /* For oom notifier event fd */ > struct list_head oom_notify; > > - /* > - * Should we move charges of a task when a task is moved into this > - * mem_cgroup ? And what type of charges should we move ? > - */ > - unsigned long move_charge_at_immigrate; > /* taken only while moving_account > 0 */ > spinlock_t move_lock; > unsigned long move_lock_flags; > diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c > index 8f88540f0159..79339cb65b9d 100644 > --- a/mm/memcontrol-v1.c > +++ b/mm/memcontrol-v1.c > @@ -40,31 +40,6 @@ static struct mem_cgroup_tree soft_limit_tree __read_mostly; > #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100 > #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2 > > -/* Stuffs for move charges at task migration. */ > -/* > - * Types of charges to be moved. > - */ > -#define MOVE_ANON 0x1ULL > -#define MOVE_FILE 0x2ULL > -#define MOVE_MASK (MOVE_ANON | MOVE_FILE) > - > -/* "mc" and its members are protected by cgroup_mutex */ > -static struct move_charge_struct { > - spinlock_t lock; /* for from, to */ > - struct mm_struct *mm; > - struct mem_cgroup *from; > - struct mem_cgroup *to; > - unsigned long flags; > - unsigned long precharge; > - unsigned long moved_charge; > - unsigned long moved_swap; > - struct task_struct *moving_task; /* a task moving charges */ > - wait_queue_head_t waitq; /* a waitq for other context */ > -} mc = { > - .lock = __SPIN_LOCK_UNLOCKED(mc.lock), > - .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq), > -}; > - > /* for OOM */ > struct mem_cgroup_eventfd_list { > struct list_head list; > @@ -426,51 +401,6 @@ unsigned long memcg1_soft_limit_reclaim(pg_data_t *pgdat, int order, > return nr_reclaimed; > } > > -/* > - * A routine for checking "mem" is under move_account() or not. > - * > - * Checking a cgroup is mc.from or mc.to or under hierarchy of > - * moving cgroups. This is for waiting at high-memory pressure > - * caused by "move". > - */ > -static bool mem_cgroup_under_move(struct mem_cgroup *memcg) > -{ > - struct mem_cgroup *from; > - struct mem_cgroup *to; > - bool ret = false; > - /* > - * Unlike task_move routines, we access mc.to, mc.from not under > - * mutual exclusion by cgroup_mutex. Here, we take spinlock instead. > - */ > - spin_lock(&mc.lock); > - from = mc.from; > - to = mc.to; > - if (!from) > - goto unlock; > - > - ret = mem_cgroup_is_descendant(from, memcg) || > - mem_cgroup_is_descendant(to, memcg); > -unlock: > - spin_unlock(&mc.lock); > - return ret; > -} > - > -bool memcg1_wait_acct_move(struct mem_cgroup *memcg) > -{ > - if (mc.moving_task && current != mc.moving_task) { > - if (mem_cgroup_under_move(memcg)) { > - DEFINE_WAIT(wait); > - prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE); > - /* moving charge context might have finished. */ > - if (mc.moving_task) > - schedule(); > - finish_wait(&mc.waitq, &wait); > - return true; > - } > - } > - return false; > -} > - > /** > * folio_memcg_lock - Bind a folio to its memcg. > * @folio: The folio. > @@ -552,44 +482,6 @@ void folio_memcg_unlock(struct folio *folio) > __folio_memcg_unlock(folio_memcg(folio)); > } > > -#ifdef CONFIG_SWAP > -/** > - * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record. > - * @entry: swap entry to be moved > - * @from: mem_cgroup which the entry is moved from > - * @to: mem_cgroup which the entry is moved to > - * > - * It succeeds only when the swap_cgroup's record for this entry is the same > - * as the mem_cgroup's id of @from. > - * > - * Returns 0 on success, -EINVAL on failure. > - * > - * The caller must have charged to @to, IOW, called page_counter_charge() about > - * both res and memsw, and called css_get(). > - */ > -static int mem_cgroup_move_swap_account(swp_entry_t entry, > - struct mem_cgroup *from, struct mem_cgroup *to) > -{ > - unsigned short old_id, new_id; > - > - old_id = mem_cgroup_id(from); > - new_id = mem_cgroup_id(to); > - > - if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { > - mod_memcg_state(from, MEMCG_SWAP, -1); > - mod_memcg_state(to, MEMCG_SWAP, 1); > - return 0; > - } > - return -EINVAL; > -} > -#else > -static inline int mem_cgroup_move_swap_account(swp_entry_t entry, > - struct mem_cgroup *from, struct mem_cgroup *to) > -{ > - return -EINVAL; > -} > -#endif > - > static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css, > struct cftype *cft) > { > @@ -600,8 +492,6 @@ static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css, > static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, > struct cftype *cft, u64 val) > { > - struct mem_cgroup *memcg = mem_cgroup_from_css(css); > - > pr_warn_once("Cgroup memory moving (move_charge_at_immigrate) is deprecated. " > "Please report your usecase to linux-mm@kvack.org if you " > "depend on this functionality.\n"); > @@ -616,760 +506,6 @@ static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, > } > #endif > > -#ifdef CONFIG_MMU > -/* Handlers for move charge at task migration. */ > -static int mem_cgroup_do_precharge(unsigned long count) > -{ > - int ret; > - > - /* Try a single bulk charge without reclaim first, kswapd may wake */ > - ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_DIRECT_RECLAIM, count); > - if (!ret) { > - mc.precharge += count; > - return ret; > - } > - > - /* Try charges one by one with reclaim, but do not retry */ > - while (count--) { > - ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1); > - if (ret) > - return ret; > - mc.precharge++; > - cond_resched(); > - } > - return 0; > -} > - > -union mc_target { > - struct folio *folio; > - swp_entry_t ent; > -}; > - > -enum mc_target_type { > - MC_TARGET_NONE = 0, > - MC_TARGET_PAGE, > - MC_TARGET_SWAP, > - MC_TARGET_DEVICE, > -}; > - > -static struct page *mc_handle_present_pte(struct vm_area_struct *vma, > - unsigned long addr, pte_t ptent) > -{ > - struct page *page = vm_normal_page(vma, addr, ptent); > - > - if (!page) > - return NULL; > - if (PageAnon(page)) { > - if (!(mc.flags & MOVE_ANON)) > - return NULL; > - } else { > - if (!(mc.flags & MOVE_FILE)) > - return NULL; > - } > - get_page(page); > - > - return page; > -} > - > -#if defined(CONFIG_SWAP) || defined(CONFIG_DEVICE_PRIVATE) > -static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, > - pte_t ptent, swp_entry_t *entry) > -{ > - struct page *page = NULL; > - swp_entry_t ent = pte_to_swp_entry(ptent); > - > - if (!(mc.flags & MOVE_ANON)) > - return NULL; > - > - /* > - * Handle device private pages that are not accessible by the CPU, but > - * stored as special swap entries in the page table. > - */ > - if (is_device_private_entry(ent)) { > - page = pfn_swap_entry_to_page(ent); > - if (!get_page_unless_zero(page)) > - return NULL; > - return page; > - } > - > - if (non_swap_entry(ent)) > - return NULL; > - > - /* > - * Because swap_cache_get_folio() updates some statistics counter, > - * we call find_get_page() with swapper_space directly. > - */ > - page = find_get_page(swap_address_space(ent), swap_cache_index(ent)); > - entry->val = ent.val; > - > - return page; > -} > -#else > -static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, > - pte_t ptent, swp_entry_t *entry) > -{ > - return NULL; > -} > -#endif > - > -static struct page *mc_handle_file_pte(struct vm_area_struct *vma, > - unsigned long addr, pte_t ptent) > -{ > - unsigned long index; > - struct folio *folio; > - > - if (!vma->vm_file) /* anonymous vma */ > - return NULL; > - if (!(mc.flags & MOVE_FILE)) > - return NULL; > - > - /* folio is moved even if it's not RSS of this task(page-faulted). */ > - /* shmem/tmpfs may report page out on swap: account for that too. */ > - index = linear_page_index(vma, addr); > - folio = filemap_get_incore_folio(vma->vm_file->f_mapping, index); > - if (IS_ERR(folio)) > - return NULL; > - return folio_file_page(folio, index); > -} > - > -static void memcg1_check_events(struct mem_cgroup *memcg, int nid); > -static void memcg1_charge_statistics(struct mem_cgroup *memcg, int nr_pages); > - > -/** > - * mem_cgroup_move_account - move account of the folio > - * @folio: The folio. > - * @compound: charge the page as compound or small page > - * @from: mem_cgroup which the folio is moved from. > - * @to: mem_cgroup which the folio is moved to. @from != @to. > - * > - * The folio must be locked and not on the LRU. > - * > - * This function doesn't do "charge" to new cgroup and doesn't do "uncharge" > - * from old cgroup. > - */ > -static int mem_cgroup_move_account(struct folio *folio, > - bool compound, > - struct mem_cgroup *from, > - struct mem_cgroup *to) > -{ > - struct lruvec *from_vec, *to_vec; > - struct pglist_data *pgdat; > - unsigned int nr_pages = compound ? folio_nr_pages(folio) : 1; > - int nid, ret; > - > - VM_BUG_ON(from == to); > - VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); > - VM_BUG_ON_FOLIO(folio_test_lru(folio), folio); > - VM_BUG_ON(compound && !folio_test_large(folio)); > - > - ret = -EINVAL; > - if (folio_memcg(folio) != from) > - goto out; > - > - pgdat = folio_pgdat(folio); > - from_vec = mem_cgroup_lruvec(from, pgdat); > - to_vec = mem_cgroup_lruvec(to, pgdat); > - > - folio_memcg_lock(folio); > - > - if (folio_test_anon(folio)) { > - if (folio_mapped(folio)) { > - __mod_lruvec_state(from_vec, NR_ANON_MAPPED, -nr_pages); > - __mod_lruvec_state(to_vec, NR_ANON_MAPPED, nr_pages); > - if (folio_test_pmd_mappable(folio)) { > - __mod_lruvec_state(from_vec, NR_ANON_THPS, > - -nr_pages); > - __mod_lruvec_state(to_vec, NR_ANON_THPS, > - nr_pages); > - } > - } > - } else { > - __mod_lruvec_state(from_vec, NR_FILE_PAGES, -nr_pages); > - __mod_lruvec_state(to_vec, NR_FILE_PAGES, nr_pages); > - > - if (folio_test_swapbacked(folio)) { > - __mod_lruvec_state(from_vec, NR_SHMEM, -nr_pages); > - __mod_lruvec_state(to_vec, NR_SHMEM, nr_pages); > - } > - > - if (folio_mapped(folio)) { > - __mod_lruvec_state(from_vec, NR_FILE_MAPPED, -nr_pages); > - __mod_lruvec_state(to_vec, NR_FILE_MAPPED, nr_pages); > - } > - > - if (folio_test_dirty(folio)) { > - struct address_space *mapping = folio_mapping(folio); > - > - if (mapping_can_writeback(mapping)) { > - __mod_lruvec_state(from_vec, NR_FILE_DIRTY, > - -nr_pages); > - __mod_lruvec_state(to_vec, NR_FILE_DIRTY, > - nr_pages); > - } > - } > - } > - > -#ifdef CONFIG_SWAP > - if (folio_test_swapcache(folio)) { > - __mod_lruvec_state(from_vec, NR_SWAPCACHE, -nr_pages); > - __mod_lruvec_state(to_vec, NR_SWAPCACHE, nr_pages); > - } > -#endif > - if (folio_test_writeback(folio)) { > - __mod_lruvec_state(from_vec, NR_WRITEBACK, -nr_pages); > - __mod_lruvec_state(to_vec, NR_WRITEBACK, nr_pages); > - } > - > - /* > - * All state has been migrated, let's switch to the new memcg. > - * > - * It is safe to change page's memcg here because the page > - * is referenced, charged, isolated, and locked: we can't race > - * with (un)charging, migration, LRU putback, or anything else > - * that would rely on a stable page's memory cgroup. > - * > - * Note that folio_memcg_lock is a memcg lock, not a page lock, > - * to save space. As soon as we switch page's memory cgroup to a > - * new memcg that isn't locked, the above state can change > - * concurrently again. Make sure we're truly done with it. > - */ > - smp_mb(); > - > - css_get(&to->css); > - css_put(&from->css); > - > - folio->memcg_data = (unsigned long)to; > - > - __folio_memcg_unlock(from); > - > - ret = 0; > - nid = folio_nid(folio); > - > - local_irq_disable(); > - memcg1_charge_statistics(to, nr_pages); > - memcg1_check_events(to, nid); > - memcg1_charge_statistics(from, -nr_pages); > - memcg1_check_events(from, nid); > - local_irq_enable(); > -out: > - return ret; > -} > - > -/** > - * get_mctgt_type - get target type of moving charge > - * @vma: the vma the pte to be checked belongs > - * @addr: the address corresponding to the pte to be checked > - * @ptent: the pte to be checked > - * @target: the pointer the target page or swap ent will be stored(can be NULL) > - * > - * Context: Called with pte lock held. > - * Return: > - * * MC_TARGET_NONE - If the pte is not a target for move charge. > - * * MC_TARGET_PAGE - If the page corresponding to this pte is a target for > - * move charge. If @target is not NULL, the folio is stored in target->folio > - * with extra refcnt taken (Caller should release it). > - * * MC_TARGET_SWAP - If the swap entry corresponding to this pte is a > - * target for charge migration. If @target is not NULL, the entry is > - * stored in target->ent. > - * * MC_TARGET_DEVICE - Like MC_TARGET_PAGE but page is device memory and > - * thus not on the lru. For now such page is charged like a regular page > - * would be as it is just special memory taking the place of a regular page. > - * See Documentations/vm/hmm.txt and include/linux/hmm.h > - */ > -static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma, > - unsigned long addr, pte_t ptent, union mc_target *target) > -{ > - struct page *page = NULL; > - struct folio *folio; > - enum mc_target_type ret = MC_TARGET_NONE; > - swp_entry_t ent = { .val = 0 }; > - > - if (pte_present(ptent)) > - page = mc_handle_present_pte(vma, addr, ptent); > - else if (pte_none_mostly(ptent)) > - /* > - * PTE markers should be treated as a none pte here, separated > - * from other swap handling below. > - */ > - page = mc_handle_file_pte(vma, addr, ptent); > - else if (is_swap_pte(ptent)) > - page = mc_handle_swap_pte(vma, ptent, &ent); > - > - if (page) > - folio = page_folio(page); > - if (target && page) { > - if (!folio_trylock(folio)) { > - folio_put(folio); > - return ret; > - } > - /* > - * page_mapped() must be stable during the move. This > - * pte is locked, so if it's present, the page cannot > - * become unmapped. If it isn't, we have only partial > - * control over the mapped state: the page lock will > - * prevent new faults against pagecache and swapcache, > - * so an unmapped page cannot become mapped. However, > - * if the page is already mapped elsewhere, it can > - * unmap, and there is nothing we can do about it. > - * Alas, skip moving the page in this case. > - */ > - if (!pte_present(ptent) && page_mapped(page)) { > - folio_unlock(folio); > - folio_put(folio); > - return ret; > - } > - } > - > - if (!page && !ent.val) > - return ret; > - if (page) { > - /* > - * Do only loose check w/o serialization. > - * mem_cgroup_move_account() checks the page is valid or > - * not under LRU exclusion. > - */ > - if (folio_memcg(folio) == mc.from) { > - ret = MC_TARGET_PAGE; > - if (folio_is_device_private(folio) || > - folio_is_device_coherent(folio)) > - ret = MC_TARGET_DEVICE; > - if (target) > - target->folio = folio; > - } > - if (!ret || !target) { > - if (target) > - folio_unlock(folio); > - folio_put(folio); > - } > - } > - /* > - * There is a swap entry and a page doesn't exist or isn't charged. > - * But we cannot move a tail-page in a THP. > - */ > - if (ent.val && !ret && (!page || !PageTransCompound(page)) && > - mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) { > - ret = MC_TARGET_SWAP; > - if (target) > - target->ent = ent; > - } > - return ret; > -} > - > -#ifdef CONFIG_TRANSPARENT_HUGEPAGE > -/* > - * We don't consider PMD mapped swapping or file mapped pages because THP does > - * not support them for now. > - * Caller should make sure that pmd_trans_huge(pmd) is true. > - */ > -static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, > - unsigned long addr, pmd_t pmd, union mc_target *target) > -{ > - struct page *page = NULL; > - struct folio *folio; > - enum mc_target_type ret = MC_TARGET_NONE; > - > - if (unlikely(is_swap_pmd(pmd))) { > - VM_BUG_ON(thp_migration_supported() && > - !is_pmd_migration_entry(pmd)); > - return ret; > - } > - page = pmd_page(pmd); > - VM_BUG_ON_PAGE(!page || !PageHead(page), page); > - folio = page_folio(page); > - if (!(mc.flags & MOVE_ANON)) > - return ret; > - if (folio_memcg(folio) == mc.from) { > - ret = MC_TARGET_PAGE; > - if (target) { > - folio_get(folio); > - if (!folio_trylock(folio)) { > - folio_put(folio); > - return MC_TARGET_NONE; > - } > - target->folio = folio; > - } > - } > - return ret; > -} > -#else > -static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, > - unsigned long addr, pmd_t pmd, union mc_target *target) > -{ > - return MC_TARGET_NONE; > -} > -#endif > - > -static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, > - unsigned long addr, unsigned long end, > - struct mm_walk *walk) > -{ > - struct vm_area_struct *vma = walk->vma; > - pte_t *pte; > - spinlock_t *ptl; > - > - ptl = pmd_trans_huge_lock(pmd, vma); > - if (ptl) { > - /* > - * Note their can not be MC_TARGET_DEVICE for now as we do not > - * support transparent huge page with MEMORY_DEVICE_PRIVATE but > - * this might change. > - */ > - if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE) > - mc.precharge += HPAGE_PMD_NR; > - spin_unlock(ptl); > - return 0; > - } > - > - pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); > - if (!pte) > - return 0; > - for (; addr != end; pte++, addr += PAGE_SIZE) > - if (get_mctgt_type(vma, addr, ptep_get(pte), NULL)) > - mc.precharge++; /* increment precharge temporarily */ > - pte_unmap_unlock(pte - 1, ptl); > - cond_resched(); > - > - return 0; > -} > - > -static const struct mm_walk_ops precharge_walk_ops = { > - .pmd_entry = mem_cgroup_count_precharge_pte_range, > - .walk_lock = PGWALK_RDLOCK, > -}; > - > -static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm) > -{ > - unsigned long precharge; > - > - mmap_read_lock(mm); > - walk_page_range(mm, 0, ULONG_MAX, &precharge_walk_ops, NULL); > - mmap_read_unlock(mm); > - > - precharge = mc.precharge; > - mc.precharge = 0; > - > - return precharge; > -} > - > -static int mem_cgroup_precharge_mc(struct mm_struct *mm) > -{ > - unsigned long precharge = mem_cgroup_count_precharge(mm); > - > - VM_BUG_ON(mc.moving_task); > - mc.moving_task = current; > - return mem_cgroup_do_precharge(precharge); > -} > - > -/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */ > -static void __mem_cgroup_clear_mc(void) > -{ > - struct mem_cgroup *from = mc.from; > - struct mem_cgroup *to = mc.to; > - > - /* we must uncharge all the leftover precharges from mc.to */ > - if (mc.precharge) { > - mem_cgroup_cancel_charge(mc.to, mc.precharge); > - mc.precharge = 0; > - } > - /* > - * we didn't uncharge from mc.from at mem_cgroup_move_account(), so > - * we must uncharge here. > - */ > - if (mc.moved_charge) { > - mem_cgroup_cancel_charge(mc.from, mc.moved_charge); > - mc.moved_charge = 0; > - } > - /* we must fixup refcnts and charges */ > - if (mc.moved_swap) { > - /* uncharge swap account from the old cgroup */ > - if (!mem_cgroup_is_root(mc.from)) > - page_counter_uncharge(&mc.from->memsw, mc.moved_swap); > - > - mem_cgroup_id_put_many(mc.from, mc.moved_swap); > - > - /* > - * we charged both to->memory and to->memsw, so we > - * should uncharge to->memory. > - */ > - if (!mem_cgroup_is_root(mc.to)) > - page_counter_uncharge(&mc.to->memory, mc.moved_swap); > - > - mc.moved_swap = 0; > - } > - memcg1_oom_recover(from); > - memcg1_oom_recover(to); > - wake_up_all(&mc.waitq); > -} > - > -static void mem_cgroup_clear_mc(void) > -{ > - struct mm_struct *mm = mc.mm; > - > - /* > - * we must clear moving_task before waking up waiters at the end of > - * task migration. > - */ > - mc.moving_task = NULL; > - __mem_cgroup_clear_mc(); > - spin_lock(&mc.lock); > - mc.from = NULL; > - mc.to = NULL; > - mc.mm = NULL; > - spin_unlock(&mc.lock); > - > - mmput(mm); > -} > - > -int memcg1_can_attach(struct cgroup_taskset *tset) > -{ > - struct cgroup_subsys_state *css; > - struct mem_cgroup *memcg = NULL; /* unneeded init to make gcc happy */ > - struct mem_cgroup *from; > - struct task_struct *leader, *p; > - struct mm_struct *mm; > - unsigned long move_flags; > - int ret = 0; > - > - /* charge immigration isn't supported on the default hierarchy */ > - if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) > - return 0; > - > - /* > - * Multi-process migrations only happen on the default hierarchy > - * where charge immigration is not used. Perform charge > - * immigration if @tset contains a leader and whine if there are > - * multiple. > - */ > - p = NULL; > - cgroup_taskset_for_each_leader(leader, css, tset) { > - WARN_ON_ONCE(p); > - p = leader; > - memcg = mem_cgroup_from_css(css); > - } > - if (!p) > - return 0; > - > - /* > - * We are now committed to this value whatever it is. Changes in this > - * tunable will only affect upcoming migrations, not the current one. > - * So we need to save it, and keep it going. > - */ > - move_flags = READ_ONCE(memcg->move_charge_at_immigrate); > - if (!move_flags) > - return 0; > - > - from = mem_cgroup_from_task(p); > - > - VM_BUG_ON(from == memcg); > - > - mm = get_task_mm(p); > - if (!mm) > - return 0; > - /* We move charges only when we move a owner of the mm */ > - if (mm->owner == p) { > - VM_BUG_ON(mc.from); > - VM_BUG_ON(mc.to); > - VM_BUG_ON(mc.precharge); > - VM_BUG_ON(mc.moved_charge); > - VM_BUG_ON(mc.moved_swap); > - > - spin_lock(&mc.lock); > - mc.mm = mm; > - mc.from = from; > - mc.to = memcg; > - mc.flags = move_flags; > - spin_unlock(&mc.lock); > - /* We set mc.moving_task later */ > - > - ret = mem_cgroup_precharge_mc(mm); > - if (ret) > - mem_cgroup_clear_mc(); > - } else { > - mmput(mm); > - } > - return ret; > -} > - > -void memcg1_cancel_attach(struct cgroup_taskset *tset) > -{ > - if (mc.to) > - mem_cgroup_clear_mc(); > -} > - > -static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, > - unsigned long addr, unsigned long end, > - struct mm_walk *walk) > -{ > - int ret = 0; > - struct vm_area_struct *vma = walk->vma; > - pte_t *pte; > - spinlock_t *ptl; > - enum mc_target_type target_type; > - union mc_target target; > - struct folio *folio; > - > - ptl = pmd_trans_huge_lock(pmd, vma); > - if (ptl) { > - if (mc.precharge < HPAGE_PMD_NR) { > - spin_unlock(ptl); > - return 0; > - } > - target_type = get_mctgt_type_thp(vma, addr, *pmd, &target); > - if (target_type == MC_TARGET_PAGE) { > - folio = target.folio; > - if (folio_isolate_lru(folio)) { > - if (!mem_cgroup_move_account(folio, true, > - mc.from, mc.to)) { > - mc.precharge -= HPAGE_PMD_NR; > - mc.moved_charge += HPAGE_PMD_NR; > - } > - folio_putback_lru(folio); > - } > - folio_unlock(folio); > - folio_put(folio); > - } else if (target_type == MC_TARGET_DEVICE) { > - folio = target.folio; > - if (!mem_cgroup_move_account(folio, true, > - mc.from, mc.to)) { > - mc.precharge -= HPAGE_PMD_NR; > - mc.moved_charge += HPAGE_PMD_NR; > - } > - folio_unlock(folio); > - folio_put(folio); > - } > - spin_unlock(ptl); > - return 0; > - } > - > -retry: > - pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); > - if (!pte) > - return 0; > - for (; addr != end; addr += PAGE_SIZE) { > - pte_t ptent = ptep_get(pte++); > - bool device = false; > - swp_entry_t ent; > - > - if (!mc.precharge) > - break; > - > - switch (get_mctgt_type(vma, addr, ptent, &target)) { > - case MC_TARGET_DEVICE: > - device = true; > - fallthrough; > - case MC_TARGET_PAGE: > - folio = target.folio; > - /* > - * We can have a part of the split pmd here. Moving it > - * can be done but it would be too convoluted so simply > - * ignore such a partial THP and keep it in original > - * memcg. There should be somebody mapping the head. > - */ > - if (folio_test_large(folio)) > - goto put; > - if (!device && !folio_isolate_lru(folio)) > - goto put; > - if (!mem_cgroup_move_account(folio, false, > - mc.from, mc.to)) { > - mc.precharge--; > - /* we uncharge from mc.from later. */ > - mc.moved_charge++; > - } > - if (!device) > - folio_putback_lru(folio); > -put: /* get_mctgt_type() gets & locks the page */ > - folio_unlock(folio); > - folio_put(folio); > - break; > - case MC_TARGET_SWAP: > - ent = target.ent; > - if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) { > - mc.precharge--; > - mem_cgroup_id_get_many(mc.to, 1); > - /* we fixup other refcnts and charges later. */ > - mc.moved_swap++; > - } > - break; > - default: > - break; > - } > - } > - pte_unmap_unlock(pte - 1, ptl); > - cond_resched(); > - > - if (addr != end) { > - /* > - * We have consumed all precharges we got in can_attach(). > - * We try charge one by one, but don't do any additional > - * charges to mc.to if we have failed in charge once in attach() > - * phase. > - */ > - ret = mem_cgroup_do_precharge(1); > - if (!ret) > - goto retry; > - } > - > - return ret; > -} > - > -static const struct mm_walk_ops charge_walk_ops = { > - .pmd_entry = mem_cgroup_move_charge_pte_range, > - .walk_lock = PGWALK_RDLOCK, > -}; > - > -static void mem_cgroup_move_charge(void) > -{ > - lru_add_drain_all(); > - /* > - * Signal folio_memcg_lock() to take the memcg's move_lock > - * while we're moving its pages to another memcg. Then wait > - * for already started RCU-only updates to finish. > - */ > - atomic_inc(&mc.from->moving_account); > - synchronize_rcu(); > -retry: > - if (unlikely(!mmap_read_trylock(mc.mm))) { > - /* > - * Someone who are holding the mmap_lock might be waiting in > - * waitq. So we cancel all extra charges, wake up all waiters, > - * and retry. Because we cancel precharges, we might not be able > - * to move enough charges, but moving charge is a best-effort > - * feature anyway, so it wouldn't be a big problem. > - */ > - __mem_cgroup_clear_mc(); > - cond_resched(); > - goto retry; > - } > - /* > - * When we have consumed all precharges and failed in doing > - * additional charge, the page walk just aborts. > - */ > - walk_page_range(mc.mm, 0, ULONG_MAX, &charge_walk_ops, NULL); > - mmap_read_unlock(mc.mm); > - atomic_dec(&mc.from->moving_account); > -} > - > -void memcg1_move_task(void) > -{ > - if (mc.to) { > - mem_cgroup_move_charge(); > - mem_cgroup_clear_mc(); > - } > -} > - > -#else /* !CONFIG_MMU */ > -int memcg1_can_attach(struct cgroup_taskset *tset) > -{ > - return 0; > -} > -void memcg1_cancel_attach(struct cgroup_taskset *tset) > -{ > -} > -void memcg1_move_task(void) > -{ > -} > -#endif > - > static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap) > { > struct mem_cgroup_threshold_ary *t; > diff --git a/mm/memcontrol-v1.h b/mm/memcontrol-v1.h > index c0672e25bcdb..0e3b82951d91 100644 > --- a/mm/memcontrol-v1.h > +++ b/mm/memcontrol-v1.h > @@ -80,12 +80,7 @@ static inline void memcg1_soft_limit_reset(struct mem_cgroup *memcg) > WRITE_ONCE(memcg->soft_limit, PAGE_COUNTER_MAX); > } > > -bool memcg1_wait_acct_move(struct mem_cgroup *memcg); > - > struct cgroup_taskset; > -int memcg1_can_attach(struct cgroup_taskset *tset); > -void memcg1_cancel_attach(struct cgroup_taskset *tset); > -void memcg1_move_task(void); > void memcg1_css_offline(struct mem_cgroup *memcg); > > /* for encoding cft->private value on file */ > @@ -130,7 +125,6 @@ static inline void memcg1_free_events(struct mem_cgroup *memcg) {} > static inline void memcg1_memcg_init(struct mem_cgroup *memcg) {} > static inline void memcg1_remove_from_trees(struct mem_cgroup *memcg) {} > static inline void memcg1_soft_limit_reset(struct mem_cgroup *memcg) {} > -static inline bool memcg1_wait_acct_move(struct mem_cgroup *memcg) { return false; } > static inline void memcg1_css_offline(struct mem_cgroup *memcg) {} > > static inline bool memcg1_oom_prepare(struct mem_cgroup *memcg, bool *locked) { return true; } > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 5c3a8629ef3e..94279b9c766a 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2242,12 +2242,6 @@ int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask, > */ > if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER)) > goto retry; > - /* > - * At task move, charge accounts can be doubly counted. So, it's > - * better to wait until the end of task_move if something is going on. > - */ > - if (memcg1_wait_acct_move(mem_over_limit)) > - goto retry; > > if (nr_retries--) > goto retry; > @@ -4439,9 +4433,6 @@ struct cgroup_subsys memory_cgrp_subsys = { > .exit = mem_cgroup_exit, > .dfl_cftypes = memory_files, > #ifdef CONFIG_MEMCG_V1 > - .can_attach = memcg1_can_attach, > - .cancel_attach = memcg1_cancel_attach, > - .post_attach = memcg1_move_task, > .legacy_cftypes = mem_cgroup_legacy_files, > #endif > .early_init = 0, > -- > 2.43.5
On Wed, Oct 23, 2024 at 11:57:11PM -0700, Shakeel Butt wrote: > The memcg-v1 charge move feature has been deprecated completely and > let's remove the relevant code as well. > > Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 524006313b0d..798db70b0a30 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -299,11 +299,6 @@ struct mem_cgroup { /* For oom notifier event fd */ struct list_head oom_notify; - /* - * Should we move charges of a task when a task is moved into this - * mem_cgroup ? And what type of charges should we move ? - */ - unsigned long move_charge_at_immigrate; /* taken only while moving_account > 0 */ spinlock_t move_lock; unsigned long move_lock_flags; diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c index 8f88540f0159..79339cb65b9d 100644 --- a/mm/memcontrol-v1.c +++ b/mm/memcontrol-v1.c @@ -40,31 +40,6 @@ static struct mem_cgroup_tree soft_limit_tree __read_mostly; #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2 -/* Stuffs for move charges at task migration. */ -/* - * Types of charges to be moved. - */ -#define MOVE_ANON 0x1ULL -#define MOVE_FILE 0x2ULL -#define MOVE_MASK (MOVE_ANON | MOVE_FILE) - -/* "mc" and its members are protected by cgroup_mutex */ -static struct move_charge_struct { - spinlock_t lock; /* for from, to */ - struct mm_struct *mm; - struct mem_cgroup *from; - struct mem_cgroup *to; - unsigned long flags; - unsigned long precharge; - unsigned long moved_charge; - unsigned long moved_swap; - struct task_struct *moving_task; /* a task moving charges */ - wait_queue_head_t waitq; /* a waitq for other context */ -} mc = { - .lock = __SPIN_LOCK_UNLOCKED(mc.lock), - .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq), -}; - /* for OOM */ struct mem_cgroup_eventfd_list { struct list_head list; @@ -426,51 +401,6 @@ unsigned long memcg1_soft_limit_reclaim(pg_data_t *pgdat, int order, return nr_reclaimed; } -/* - * A routine for checking "mem" is under move_account() or not. - * - * Checking a cgroup is mc.from or mc.to or under hierarchy of - * moving cgroups. This is for waiting at high-memory pressure - * caused by "move". - */ -static bool mem_cgroup_under_move(struct mem_cgroup *memcg) -{ - struct mem_cgroup *from; - struct mem_cgroup *to; - bool ret = false; - /* - * Unlike task_move routines, we access mc.to, mc.from not under - * mutual exclusion by cgroup_mutex. Here, we take spinlock instead. - */ - spin_lock(&mc.lock); - from = mc.from; - to = mc.to; - if (!from) - goto unlock; - - ret = mem_cgroup_is_descendant(from, memcg) || - mem_cgroup_is_descendant(to, memcg); -unlock: - spin_unlock(&mc.lock); - return ret; -} - -bool memcg1_wait_acct_move(struct mem_cgroup *memcg) -{ - if (mc.moving_task && current != mc.moving_task) { - if (mem_cgroup_under_move(memcg)) { - DEFINE_WAIT(wait); - prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE); - /* moving charge context might have finished. */ - if (mc.moving_task) - schedule(); - finish_wait(&mc.waitq, &wait); - return true; - } - } - return false; -} - /** * folio_memcg_lock - Bind a folio to its memcg. * @folio: The folio. @@ -552,44 +482,6 @@ void folio_memcg_unlock(struct folio *folio) __folio_memcg_unlock(folio_memcg(folio)); } -#ifdef CONFIG_SWAP -/** - * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record. - * @entry: swap entry to be moved - * @from: mem_cgroup which the entry is moved from - * @to: mem_cgroup which the entry is moved to - * - * It succeeds only when the swap_cgroup's record for this entry is the same - * as the mem_cgroup's id of @from. - * - * Returns 0 on success, -EINVAL on failure. - * - * The caller must have charged to @to, IOW, called page_counter_charge() about - * both res and memsw, and called css_get(). - */ -static int mem_cgroup_move_swap_account(swp_entry_t entry, - struct mem_cgroup *from, struct mem_cgroup *to) -{ - unsigned short old_id, new_id; - - old_id = mem_cgroup_id(from); - new_id = mem_cgroup_id(to); - - if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { - mod_memcg_state(from, MEMCG_SWAP, -1); - mod_memcg_state(to, MEMCG_SWAP, 1); - return 0; - } - return -EINVAL; -} -#else -static inline int mem_cgroup_move_swap_account(swp_entry_t entry, - struct mem_cgroup *from, struct mem_cgroup *to) -{ - return -EINVAL; -} -#endif - static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css, struct cftype *cft) { @@ -600,8 +492,6 @@ static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css, static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, struct cftype *cft, u64 val) { - struct mem_cgroup *memcg = mem_cgroup_from_css(css); - pr_warn_once("Cgroup memory moving (move_charge_at_immigrate) is deprecated. " "Please report your usecase to linux-mm@kvack.org if you " "depend on this functionality.\n"); @@ -616,760 +506,6 @@ static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, } #endif -#ifdef CONFIG_MMU -/* Handlers for move charge at task migration. */ -static int mem_cgroup_do_precharge(unsigned long count) -{ - int ret; - - /* Try a single bulk charge without reclaim first, kswapd may wake */ - ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_DIRECT_RECLAIM, count); - if (!ret) { - mc.precharge += count; - return ret; - } - - /* Try charges one by one with reclaim, but do not retry */ - while (count--) { - ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1); - if (ret) - return ret; - mc.precharge++; - cond_resched(); - } - return 0; -} - -union mc_target { - struct folio *folio; - swp_entry_t ent; -}; - -enum mc_target_type { - MC_TARGET_NONE = 0, - MC_TARGET_PAGE, - MC_TARGET_SWAP, - MC_TARGET_DEVICE, -}; - -static struct page *mc_handle_present_pte(struct vm_area_struct *vma, - unsigned long addr, pte_t ptent) -{ - struct page *page = vm_normal_page(vma, addr, ptent); - - if (!page) - return NULL; - if (PageAnon(page)) { - if (!(mc.flags & MOVE_ANON)) - return NULL; - } else { - if (!(mc.flags & MOVE_FILE)) - return NULL; - } - get_page(page); - - return page; -} - -#if defined(CONFIG_SWAP) || defined(CONFIG_DEVICE_PRIVATE) -static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, - pte_t ptent, swp_entry_t *entry) -{ - struct page *page = NULL; - swp_entry_t ent = pte_to_swp_entry(ptent); - - if (!(mc.flags & MOVE_ANON)) - return NULL; - - /* - * Handle device private pages that are not accessible by the CPU, but - * stored as special swap entries in the page table. - */ - if (is_device_private_entry(ent)) { - page = pfn_swap_entry_to_page(ent); - if (!get_page_unless_zero(page)) - return NULL; - return page; - } - - if (non_swap_entry(ent)) - return NULL; - - /* - * Because swap_cache_get_folio() updates some statistics counter, - * we call find_get_page() with swapper_space directly. - */ - page = find_get_page(swap_address_space(ent), swap_cache_index(ent)); - entry->val = ent.val; - - return page; -} -#else -static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, - pte_t ptent, swp_entry_t *entry) -{ - return NULL; -} -#endif - -static struct page *mc_handle_file_pte(struct vm_area_struct *vma, - unsigned long addr, pte_t ptent) -{ - unsigned long index; - struct folio *folio; - - if (!vma->vm_file) /* anonymous vma */ - return NULL; - if (!(mc.flags & MOVE_FILE)) - return NULL; - - /* folio is moved even if it's not RSS of this task(page-faulted). */ - /* shmem/tmpfs may report page out on swap: account for that too. */ - index = linear_page_index(vma, addr); - folio = filemap_get_incore_folio(vma->vm_file->f_mapping, index); - if (IS_ERR(folio)) - return NULL; - return folio_file_page(folio, index); -} - -static void memcg1_check_events(struct mem_cgroup *memcg, int nid); -static void memcg1_charge_statistics(struct mem_cgroup *memcg, int nr_pages); - -/** - * mem_cgroup_move_account - move account of the folio - * @folio: The folio. - * @compound: charge the page as compound or small page - * @from: mem_cgroup which the folio is moved from. - * @to: mem_cgroup which the folio is moved to. @from != @to. - * - * The folio must be locked and not on the LRU. - * - * This function doesn't do "charge" to new cgroup and doesn't do "uncharge" - * from old cgroup. - */ -static int mem_cgroup_move_account(struct folio *folio, - bool compound, - struct mem_cgroup *from, - struct mem_cgroup *to) -{ - struct lruvec *from_vec, *to_vec; - struct pglist_data *pgdat; - unsigned int nr_pages = compound ? folio_nr_pages(folio) : 1; - int nid, ret; - - VM_BUG_ON(from == to); - VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); - VM_BUG_ON_FOLIO(folio_test_lru(folio), folio); - VM_BUG_ON(compound && !folio_test_large(folio)); - - ret = -EINVAL; - if (folio_memcg(folio) != from) - goto out; - - pgdat = folio_pgdat(folio); - from_vec = mem_cgroup_lruvec(from, pgdat); - to_vec = mem_cgroup_lruvec(to, pgdat); - - folio_memcg_lock(folio); - - if (folio_test_anon(folio)) { - if (folio_mapped(folio)) { - __mod_lruvec_state(from_vec, NR_ANON_MAPPED, -nr_pages); - __mod_lruvec_state(to_vec, NR_ANON_MAPPED, nr_pages); - if (folio_test_pmd_mappable(folio)) { - __mod_lruvec_state(from_vec, NR_ANON_THPS, - -nr_pages); - __mod_lruvec_state(to_vec, NR_ANON_THPS, - nr_pages); - } - } - } else { - __mod_lruvec_state(from_vec, NR_FILE_PAGES, -nr_pages); - __mod_lruvec_state(to_vec, NR_FILE_PAGES, nr_pages); - - if (folio_test_swapbacked(folio)) { - __mod_lruvec_state(from_vec, NR_SHMEM, -nr_pages); - __mod_lruvec_state(to_vec, NR_SHMEM, nr_pages); - } - - if (folio_mapped(folio)) { - __mod_lruvec_state(from_vec, NR_FILE_MAPPED, -nr_pages); - __mod_lruvec_state(to_vec, NR_FILE_MAPPED, nr_pages); - } - - if (folio_test_dirty(folio)) { - struct address_space *mapping = folio_mapping(folio); - - if (mapping_can_writeback(mapping)) { - __mod_lruvec_state(from_vec, NR_FILE_DIRTY, - -nr_pages); - __mod_lruvec_state(to_vec, NR_FILE_DIRTY, - nr_pages); - } - } - } - -#ifdef CONFIG_SWAP - if (folio_test_swapcache(folio)) { - __mod_lruvec_state(from_vec, NR_SWAPCACHE, -nr_pages); - __mod_lruvec_state(to_vec, NR_SWAPCACHE, nr_pages); - } -#endif - if (folio_test_writeback(folio)) { - __mod_lruvec_state(from_vec, NR_WRITEBACK, -nr_pages); - __mod_lruvec_state(to_vec, NR_WRITEBACK, nr_pages); - } - - /* - * All state has been migrated, let's switch to the new memcg. - * - * It is safe to change page's memcg here because the page - * is referenced, charged, isolated, and locked: we can't race - * with (un)charging, migration, LRU putback, or anything else - * that would rely on a stable page's memory cgroup. - * - * Note that folio_memcg_lock is a memcg lock, not a page lock, - * to save space. As soon as we switch page's memory cgroup to a - * new memcg that isn't locked, the above state can change - * concurrently again. Make sure we're truly done with it. - */ - smp_mb(); - - css_get(&to->css); - css_put(&from->css); - - folio->memcg_data = (unsigned long)to; - - __folio_memcg_unlock(from); - - ret = 0; - nid = folio_nid(folio); - - local_irq_disable(); - memcg1_charge_statistics(to, nr_pages); - memcg1_check_events(to, nid); - memcg1_charge_statistics(from, -nr_pages); - memcg1_check_events(from, nid); - local_irq_enable(); -out: - return ret; -} - -/** - * get_mctgt_type - get target type of moving charge - * @vma: the vma the pte to be checked belongs - * @addr: the address corresponding to the pte to be checked - * @ptent: the pte to be checked - * @target: the pointer the target page or swap ent will be stored(can be NULL) - * - * Context: Called with pte lock held. - * Return: - * * MC_TARGET_NONE - If the pte is not a target for move charge. - * * MC_TARGET_PAGE - If the page corresponding to this pte is a target for - * move charge. If @target is not NULL, the folio is stored in target->folio - * with extra refcnt taken (Caller should release it). - * * MC_TARGET_SWAP - If the swap entry corresponding to this pte is a - * target for charge migration. If @target is not NULL, the entry is - * stored in target->ent. - * * MC_TARGET_DEVICE - Like MC_TARGET_PAGE but page is device memory and - * thus not on the lru. For now such page is charged like a regular page - * would be as it is just special memory taking the place of a regular page. - * See Documentations/vm/hmm.txt and include/linux/hmm.h - */ -static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma, - unsigned long addr, pte_t ptent, union mc_target *target) -{ - struct page *page = NULL; - struct folio *folio; - enum mc_target_type ret = MC_TARGET_NONE; - swp_entry_t ent = { .val = 0 }; - - if (pte_present(ptent)) - page = mc_handle_present_pte(vma, addr, ptent); - else if (pte_none_mostly(ptent)) - /* - * PTE markers should be treated as a none pte here, separated - * from other swap handling below. - */ - page = mc_handle_file_pte(vma, addr, ptent); - else if (is_swap_pte(ptent)) - page = mc_handle_swap_pte(vma, ptent, &ent); - - if (page) - folio = page_folio(page); - if (target && page) { - if (!folio_trylock(folio)) { - folio_put(folio); - return ret; - } - /* - * page_mapped() must be stable during the move. This - * pte is locked, so if it's present, the page cannot - * become unmapped. If it isn't, we have only partial - * control over the mapped state: the page lock will - * prevent new faults against pagecache and swapcache, - * so an unmapped page cannot become mapped. However, - * if the page is already mapped elsewhere, it can - * unmap, and there is nothing we can do about it. - * Alas, skip moving the page in this case. - */ - if (!pte_present(ptent) && page_mapped(page)) { - folio_unlock(folio); - folio_put(folio); - return ret; - } - } - - if (!page && !ent.val) - return ret; - if (page) { - /* - * Do only loose check w/o serialization. - * mem_cgroup_move_account() checks the page is valid or - * not under LRU exclusion. - */ - if (folio_memcg(folio) == mc.from) { - ret = MC_TARGET_PAGE; - if (folio_is_device_private(folio) || - folio_is_device_coherent(folio)) - ret = MC_TARGET_DEVICE; - if (target) - target->folio = folio; - } - if (!ret || !target) { - if (target) - folio_unlock(folio); - folio_put(folio); - } - } - /* - * There is a swap entry and a page doesn't exist or isn't charged. - * But we cannot move a tail-page in a THP. - */ - if (ent.val && !ret && (!page || !PageTransCompound(page)) && - mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) { - ret = MC_TARGET_SWAP; - if (target) - target->ent = ent; - } - return ret; -} - -#ifdef CONFIG_TRANSPARENT_HUGEPAGE -/* - * We don't consider PMD mapped swapping or file mapped pages because THP does - * not support them for now. - * Caller should make sure that pmd_trans_huge(pmd) is true. - */ -static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, - unsigned long addr, pmd_t pmd, union mc_target *target) -{ - struct page *page = NULL; - struct folio *folio; - enum mc_target_type ret = MC_TARGET_NONE; - - if (unlikely(is_swap_pmd(pmd))) { - VM_BUG_ON(thp_migration_supported() && - !is_pmd_migration_entry(pmd)); - return ret; - } - page = pmd_page(pmd); - VM_BUG_ON_PAGE(!page || !PageHead(page), page); - folio = page_folio(page); - if (!(mc.flags & MOVE_ANON)) - return ret; - if (folio_memcg(folio) == mc.from) { - ret = MC_TARGET_PAGE; - if (target) { - folio_get(folio); - if (!folio_trylock(folio)) { - folio_put(folio); - return MC_TARGET_NONE; - } - target->folio = folio; - } - } - return ret; -} -#else -static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma, - unsigned long addr, pmd_t pmd, union mc_target *target) -{ - return MC_TARGET_NONE; -} -#endif - -static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, - unsigned long addr, unsigned long end, - struct mm_walk *walk) -{ - struct vm_area_struct *vma = walk->vma; - pte_t *pte; - spinlock_t *ptl; - - ptl = pmd_trans_huge_lock(pmd, vma); - if (ptl) { - /* - * Note their can not be MC_TARGET_DEVICE for now as we do not - * support transparent huge page with MEMORY_DEVICE_PRIVATE but - * this might change. - */ - if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE) - mc.precharge += HPAGE_PMD_NR; - spin_unlock(ptl); - return 0; - } - - pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); - if (!pte) - return 0; - for (; addr != end; pte++, addr += PAGE_SIZE) - if (get_mctgt_type(vma, addr, ptep_get(pte), NULL)) - mc.precharge++; /* increment precharge temporarily */ - pte_unmap_unlock(pte - 1, ptl); - cond_resched(); - - return 0; -} - -static const struct mm_walk_ops precharge_walk_ops = { - .pmd_entry = mem_cgroup_count_precharge_pte_range, - .walk_lock = PGWALK_RDLOCK, -}; - -static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm) -{ - unsigned long precharge; - - mmap_read_lock(mm); - walk_page_range(mm, 0, ULONG_MAX, &precharge_walk_ops, NULL); - mmap_read_unlock(mm); - - precharge = mc.precharge; - mc.precharge = 0; - - return precharge; -} - -static int mem_cgroup_precharge_mc(struct mm_struct *mm) -{ - unsigned long precharge = mem_cgroup_count_precharge(mm); - - VM_BUG_ON(mc.moving_task); - mc.moving_task = current; - return mem_cgroup_do_precharge(precharge); -} - -/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */ -static void __mem_cgroup_clear_mc(void) -{ - struct mem_cgroup *from = mc.from; - struct mem_cgroup *to = mc.to; - - /* we must uncharge all the leftover precharges from mc.to */ - if (mc.precharge) { - mem_cgroup_cancel_charge(mc.to, mc.precharge); - mc.precharge = 0; - } - /* - * we didn't uncharge from mc.from at mem_cgroup_move_account(), so - * we must uncharge here. - */ - if (mc.moved_charge) { - mem_cgroup_cancel_charge(mc.from, mc.moved_charge); - mc.moved_charge = 0; - } - /* we must fixup refcnts and charges */ - if (mc.moved_swap) { - /* uncharge swap account from the old cgroup */ - if (!mem_cgroup_is_root(mc.from)) - page_counter_uncharge(&mc.from->memsw, mc.moved_swap); - - mem_cgroup_id_put_many(mc.from, mc.moved_swap); - - /* - * we charged both to->memory and to->memsw, so we - * should uncharge to->memory. - */ - if (!mem_cgroup_is_root(mc.to)) - page_counter_uncharge(&mc.to->memory, mc.moved_swap); - - mc.moved_swap = 0; - } - memcg1_oom_recover(from); - memcg1_oom_recover(to); - wake_up_all(&mc.waitq); -} - -static void mem_cgroup_clear_mc(void) -{ - struct mm_struct *mm = mc.mm; - - /* - * we must clear moving_task before waking up waiters at the end of - * task migration. - */ - mc.moving_task = NULL; - __mem_cgroup_clear_mc(); - spin_lock(&mc.lock); - mc.from = NULL; - mc.to = NULL; - mc.mm = NULL; - spin_unlock(&mc.lock); - - mmput(mm); -} - -int memcg1_can_attach(struct cgroup_taskset *tset) -{ - struct cgroup_subsys_state *css; - struct mem_cgroup *memcg = NULL; /* unneeded init to make gcc happy */ - struct mem_cgroup *from; - struct task_struct *leader, *p; - struct mm_struct *mm; - unsigned long move_flags; - int ret = 0; - - /* charge immigration isn't supported on the default hierarchy */ - if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) - return 0; - - /* - * Multi-process migrations only happen on the default hierarchy - * where charge immigration is not used. Perform charge - * immigration if @tset contains a leader and whine if there are - * multiple. - */ - p = NULL; - cgroup_taskset_for_each_leader(leader, css, tset) { - WARN_ON_ONCE(p); - p = leader; - memcg = mem_cgroup_from_css(css); - } - if (!p) - return 0; - - /* - * We are now committed to this value whatever it is. Changes in this - * tunable will only affect upcoming migrations, not the current one. - * So we need to save it, and keep it going. - */ - move_flags = READ_ONCE(memcg->move_charge_at_immigrate); - if (!move_flags) - return 0; - - from = mem_cgroup_from_task(p); - - VM_BUG_ON(from == memcg); - - mm = get_task_mm(p); - if (!mm) - return 0; - /* We move charges only when we move a owner of the mm */ - if (mm->owner == p) { - VM_BUG_ON(mc.from); - VM_BUG_ON(mc.to); - VM_BUG_ON(mc.precharge); - VM_BUG_ON(mc.moved_charge); - VM_BUG_ON(mc.moved_swap); - - spin_lock(&mc.lock); - mc.mm = mm; - mc.from = from; - mc.to = memcg; - mc.flags = move_flags; - spin_unlock(&mc.lock); - /* We set mc.moving_task later */ - - ret = mem_cgroup_precharge_mc(mm); - if (ret) - mem_cgroup_clear_mc(); - } else { - mmput(mm); - } - return ret; -} - -void memcg1_cancel_attach(struct cgroup_taskset *tset) -{ - if (mc.to) - mem_cgroup_clear_mc(); -} - -static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, - unsigned long addr, unsigned long end, - struct mm_walk *walk) -{ - int ret = 0; - struct vm_area_struct *vma = walk->vma; - pte_t *pte; - spinlock_t *ptl; - enum mc_target_type target_type; - union mc_target target; - struct folio *folio; - - ptl = pmd_trans_huge_lock(pmd, vma); - if (ptl) { - if (mc.precharge < HPAGE_PMD_NR) { - spin_unlock(ptl); - return 0; - } - target_type = get_mctgt_type_thp(vma, addr, *pmd, &target); - if (target_type == MC_TARGET_PAGE) { - folio = target.folio; - if (folio_isolate_lru(folio)) { - if (!mem_cgroup_move_account(folio, true, - mc.from, mc.to)) { - mc.precharge -= HPAGE_PMD_NR; - mc.moved_charge += HPAGE_PMD_NR; - } - folio_putback_lru(folio); - } - folio_unlock(folio); - folio_put(folio); - } else if (target_type == MC_TARGET_DEVICE) { - folio = target.folio; - if (!mem_cgroup_move_account(folio, true, - mc.from, mc.to)) { - mc.precharge -= HPAGE_PMD_NR; - mc.moved_charge += HPAGE_PMD_NR; - } - folio_unlock(folio); - folio_put(folio); - } - spin_unlock(ptl); - return 0; - } - -retry: - pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); - if (!pte) - return 0; - for (; addr != end; addr += PAGE_SIZE) { - pte_t ptent = ptep_get(pte++); - bool device = false; - swp_entry_t ent; - - if (!mc.precharge) - break; - - switch (get_mctgt_type(vma, addr, ptent, &target)) { - case MC_TARGET_DEVICE: - device = true; - fallthrough; - case MC_TARGET_PAGE: - folio = target.folio; - /* - * We can have a part of the split pmd here. Moving it - * can be done but it would be too convoluted so simply - * ignore such a partial THP and keep it in original - * memcg. There should be somebody mapping the head. - */ - if (folio_test_large(folio)) - goto put; - if (!device && !folio_isolate_lru(folio)) - goto put; - if (!mem_cgroup_move_account(folio, false, - mc.from, mc.to)) { - mc.precharge--; - /* we uncharge from mc.from later. */ - mc.moved_charge++; - } - if (!device) - folio_putback_lru(folio); -put: /* get_mctgt_type() gets & locks the page */ - folio_unlock(folio); - folio_put(folio); - break; - case MC_TARGET_SWAP: - ent = target.ent; - if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) { - mc.precharge--; - mem_cgroup_id_get_many(mc.to, 1); - /* we fixup other refcnts and charges later. */ - mc.moved_swap++; - } - break; - default: - break; - } - } - pte_unmap_unlock(pte - 1, ptl); - cond_resched(); - - if (addr != end) { - /* - * We have consumed all precharges we got in can_attach(). - * We try charge one by one, but don't do any additional - * charges to mc.to if we have failed in charge once in attach() - * phase. - */ - ret = mem_cgroup_do_precharge(1); - if (!ret) - goto retry; - } - - return ret; -} - -static const struct mm_walk_ops charge_walk_ops = { - .pmd_entry = mem_cgroup_move_charge_pte_range, - .walk_lock = PGWALK_RDLOCK, -}; - -static void mem_cgroup_move_charge(void) -{ - lru_add_drain_all(); - /* - * Signal folio_memcg_lock() to take the memcg's move_lock - * while we're moving its pages to another memcg. Then wait - * for already started RCU-only updates to finish. - */ - atomic_inc(&mc.from->moving_account); - synchronize_rcu(); -retry: - if (unlikely(!mmap_read_trylock(mc.mm))) { - /* - * Someone who are holding the mmap_lock might be waiting in - * waitq. So we cancel all extra charges, wake up all waiters, - * and retry. Because we cancel precharges, we might not be able - * to move enough charges, but moving charge is a best-effort - * feature anyway, so it wouldn't be a big problem. - */ - __mem_cgroup_clear_mc(); - cond_resched(); - goto retry; - } - /* - * When we have consumed all precharges and failed in doing - * additional charge, the page walk just aborts. - */ - walk_page_range(mc.mm, 0, ULONG_MAX, &charge_walk_ops, NULL); - mmap_read_unlock(mc.mm); - atomic_dec(&mc.from->moving_account); -} - -void memcg1_move_task(void) -{ - if (mc.to) { - mem_cgroup_move_charge(); - mem_cgroup_clear_mc(); - } -} - -#else /* !CONFIG_MMU */ -int memcg1_can_attach(struct cgroup_taskset *tset) -{ - return 0; -} -void memcg1_cancel_attach(struct cgroup_taskset *tset) -{ -} -void memcg1_move_task(void) -{ -} -#endif - static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap) { struct mem_cgroup_threshold_ary *t; diff --git a/mm/memcontrol-v1.h b/mm/memcontrol-v1.h index c0672e25bcdb..0e3b82951d91 100644 --- a/mm/memcontrol-v1.h +++ b/mm/memcontrol-v1.h @@ -80,12 +80,7 @@ static inline void memcg1_soft_limit_reset(struct mem_cgroup *memcg) WRITE_ONCE(memcg->soft_limit, PAGE_COUNTER_MAX); } -bool memcg1_wait_acct_move(struct mem_cgroup *memcg); - struct cgroup_taskset; -int memcg1_can_attach(struct cgroup_taskset *tset); -void memcg1_cancel_attach(struct cgroup_taskset *tset); -void memcg1_move_task(void); void memcg1_css_offline(struct mem_cgroup *memcg); /* for encoding cft->private value on file */ @@ -130,7 +125,6 @@ static inline void memcg1_free_events(struct mem_cgroup *memcg) {} static inline void memcg1_memcg_init(struct mem_cgroup *memcg) {} static inline void memcg1_remove_from_trees(struct mem_cgroup *memcg) {} static inline void memcg1_soft_limit_reset(struct mem_cgroup *memcg) {} -static inline bool memcg1_wait_acct_move(struct mem_cgroup *memcg) { return false; } static inline void memcg1_css_offline(struct mem_cgroup *memcg) {} static inline bool memcg1_oom_prepare(struct mem_cgroup *memcg, bool *locked) { return true; } diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 5c3a8629ef3e..94279b9c766a 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2242,12 +2242,6 @@ int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask, */ if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER)) goto retry; - /* - * At task move, charge accounts can be doubly counted. So, it's - * better to wait until the end of task_move if something is going on. - */ - if (memcg1_wait_acct_move(mem_over_limit)) - goto retry; if (nr_retries--) goto retry; @@ -4439,9 +4433,6 @@ struct cgroup_subsys memory_cgrp_subsys = { .exit = mem_cgroup_exit, .dfl_cftypes = memory_files, #ifdef CONFIG_MEMCG_V1 - .can_attach = memcg1_can_attach, - .cancel_attach = memcg1_cancel_attach, - .post_attach = memcg1_move_task, .legacy_cftypes = mem_cgroup_legacy_files, #endif .early_init = 0,
The memcg-v1 charge move feature has been deprecated completely and let's remove the relevant code as well. Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> --- include/linux/memcontrol.h | 5 - mm/memcontrol-v1.c | 864 ------------------------------------- mm/memcontrol-v1.h | 6 - mm/memcontrol.c | 9 - 4 files changed, 884 deletions(-)