diff options
| -rw-r--r-- | include/linux/memcontrol.h | 50 | ||||
| -rw-r--r-- | include/linux/sched.h | 7 | ||||
| -rw-r--r-- | mm/filemap.c | 11 | ||||
| -rw-r--r-- | mm/memcontrol.c | 139 | ||||
| -rw-r--r-- | mm/memory.c | 18 | ||||
| -rw-r--r-- | mm/oom_kill.c | 2 |
6 files changed, 79 insertions, 148 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 64591ffc2e2c..a3b4812f494f 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -124,47 +124,24 @@ extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, extern void mem_cgroup_replace_page_cache(struct page *oldpage, struct page *newpage); -/** - * mem_cgroup_toggle_oom - toggle the memcg OOM killer for the current task - * @new: true to enable, false to disable - * - * Toggle whether a failed memcg charge should invoke the OOM killer - * or just return -ENOMEM. Returns the previous toggle state. - * - * NOTE: Any path that enables the OOM killer before charging must - * call mem_cgroup_oom_synchronize() afterward to finalize the - * OOM handling and clean up. - */ -static inline bool mem_cgroup_toggle_oom(bool new) +static inline void mem_cgroup_oom_enable(void) { - bool old; - - old = current->memcg_oom.may_oom; - current->memcg_oom.may_oom = new; - - return old; + WARN_ON(current->memcg_oom.may_oom); + current->memcg_oom.may_oom = 1; } -static inline void mem_cgroup_enable_oom(void) +static inline void mem_cgroup_oom_disable(void) { - bool old = mem_cgroup_toggle_oom(true); - - WARN_ON(old == true); -} - -static inline void mem_cgroup_disable_oom(void) -{ - bool old = mem_cgroup_toggle_oom(false); - - WARN_ON(old == false); + WARN_ON(!current->memcg_oom.may_oom); + current->memcg_oom.may_oom = 0; } static inline bool task_in_memcg_oom(struct task_struct *p) { - return p->memcg_oom.in_memcg_oom; + return p->memcg_oom.memcg; } -bool mem_cgroup_oom_synchronize(void); +bool mem_cgroup_oom_synchronize(bool wait); #ifdef CONFIG_MEMCG_SWAP extern int do_swap_account; @@ -389,16 +366,11 @@ static inline void mem_cgroup_end_update_page_stat(struct page *page, { } -static inline bool mem_cgroup_toggle_oom(bool new) -{ - return false; -} - -static inline void mem_cgroup_enable_oom(void) +static inline void mem_cgroup_oom_enable(void) { } -static inline void mem_cgroup_disable_oom(void) +static inline void mem_cgroup_oom_disable(void) { } @@ -407,7 +379,7 @@ static inline bool task_in_memcg_oom(struct task_struct *p) return false; } -static inline bool mem_cgroup_oom_synchronize(void) +static inline bool mem_cgroup_oom_synchronize(bool wait) { return false; } diff --git a/include/linux/sched.h b/include/linux/sched.h index a1b7e6ee453b..00c1d4f45072 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1412,11 +1412,10 @@ struct task_struct { } memcg_batch; unsigned int memcg_kmem_skip_account; struct memcg_oom_info { + struct mem_cgroup *memcg; + gfp_t gfp_mask; + int order; unsigned int may_oom:1; - unsigned int in_memcg_oom:1; - unsigned int oom_locked:1; - int wakeups; - struct mem_cgroup *wait_on_memcg; } memcg_oom; #endif #ifdef CONFIG_HAVE_HW_BREAKPOINT diff --git a/mm/filemap.c b/mm/filemap.c index c466f4c449e9..7905fe721aa8 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1614,7 +1614,6 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) struct inode *inode = mapping->host; pgoff_t offset = vmf->pgoff; struct page *page; - bool memcg_oom; pgoff_t size; int ret = 0; @@ -1623,11 +1622,7 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) return VM_FAULT_SIGBUS; /* - * Do we have something in the page cache already? Either - * way, try readahead, but disable the memcg OOM killer for it - * as readahead is optional and no errors are propagated up - * the fault stack. The OOM killer is enabled while trying to - * instantiate the faulting page individually below. + * Do we have something in the page cache already? */ page = find_get_page(mapping, offset); if (likely(page) && !(vmf->flags & FAULT_FLAG_TRIED)) { @@ -1635,14 +1630,10 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) * We found the page, so try async readahead before * waiting for the lock. */ - memcg_oom = mem_cgroup_toggle_oom(false); do_async_mmap_readahead(vma, ra, file, page, offset); - mem_cgroup_toggle_oom(memcg_oom); } else if (!page) { /* No page in the page cache at all */ - memcg_oom = mem_cgroup_toggle_oom(false); do_sync_mmap_readahead(vma, ra, file, offset); - mem_cgroup_toggle_oom(memcg_oom); count_vm_event(PGMAJFAULT); mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); ret = VM_FAULT_MAJOR; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 7849660665d7..eaa3accb01e7 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2191,110 +2191,59 @@ static void memcg_oom_recover(struct mem_cgroup *memcg) memcg_wakeup_oom(memcg); } -/* - * try to call OOM killer - */ static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order) { - bool locked; - int wakeups; - if (!current->memcg_oom.may_oom) return; - - current->memcg_oom.in_memcg_oom = 1; - /* - * As with any blocking lock, a contender needs to start - * listening for wakeups before attempting the trylock, - * otherwise it can miss the wakeup from the unlock and sleep - * indefinitely. This is just open-coded because our locking - * is so particular to memcg hierarchies. + * We are in the middle of the charge context here, so we + * don't want to block when potentially sitting on a callstack + * that holds all kinds of filesystem and mm locks. + * + * Also, the caller may handle a failed allocation gracefully + * (like optional page cache readahead) and so an OOM killer + * invocation might not even be necessary. + * + * That's why we don't do anything here except remember the + * OOM context and then deal with it at the end of the page + * fault when the stack is unwound, the locks are released, + * and when we know whether the fault was overall successful. */ - wakeups = atomic_read(&memcg->oom_wakeups); - mem_cgroup_mark_under_oom(memcg); - - locked = mem_cgroup_oom_trylock(memcg); - - if (locked) - mem_cgroup_oom_notify(memcg); - - if (locked && !memcg->oom_kill_disable) { - mem_cgroup_unmark_under_oom(memcg); - mem_cgroup_out_of_memory(memcg, mask, order); - mem_cgroup_oom_unlock(memcg); - /* - * There is no guarantee that an OOM-lock contender - * sees the wakeups triggered by the OOM kill - * uncharges. Wake any sleepers explicitely. - */ - memcg_oom_recover(memcg); - } else { - /* - * A system call can just return -ENOMEM, but if this - * is a page fault and somebody else is handling the - * OOM already, we need to sleep on the OOM waitqueue - * for this memcg until the situation is resolved. - * Which can take some time because it might be - * handled by a userspace task. - * - * However, this is the charge context, which means - * that we may sit on a large call stack and hold - * various filesystem locks, the mmap_sem etc. and we - * don't want the OOM handler to deadlock on them - * while we sit here and wait. Store the current OOM - * context in the task_struct, then return -ENOMEM. - * At the end of the page fault handler, with the - * stack unwound, pagefault_out_of_memory() will check - * back with us by calling - * mem_cgroup_oom_synchronize(), possibly putting the - * task to sleep. - */ - current->memcg_oom.oom_locked = locked; - current->memcg_oom.wakeups = wakeups; - css_get(&memcg->css); - current->memcg_oom.wait_on_memcg = memcg; - } + css_get(&memcg->css); + current->memcg_oom.memcg = memcg; + current->memcg_oom.gfp_mask = mask; + current->memcg_oom.order = order; } /** * mem_cgroup_oom_synchronize - complete memcg OOM handling + * @handle: actually kill/wait or just clean up the OOM state * - * This has to be called at the end of a page fault if the the memcg - * OOM handler was enabled and the fault is returning %VM_FAULT_OOM. + * This has to be called at the end of a page fault if the memcg OOM + * handler was enabled. * - * Memcg supports userspace OOM handling, so failed allocations must + * Memcg supports userspace OOM handling where failed allocations must * sleep on a waitqueue until the userspace task resolves the * situation. Sleeping directly in the charge context with all kinds * of locks held is not a good idea, instead we remember an OOM state * in the task and mem_cgroup_oom_synchronize() has to be called at - * the end of the page fault to put the task to sleep and clean up the - * OOM state. + * the end of the page fault to complete the OOM handling. * * Returns %true if an ongoing memcg OOM situation was detected and - * finalized, %false otherwise. + * completed, %false otherwise. */ -bool mem_cgroup_oom_synchronize(void) +bool mem_cgroup_oom_synchronize(bool handle) { + struct mem_cgroup *memcg = current->memcg_oom.memcg; struct oom_wait_info owait; - struct mem_cgroup *memcg; + bool locked; /* OOM is global, do not handle */ - if (!current->memcg_oom.in_memcg_oom) - return false; - - /* - * We invoked the OOM killer but there is a chance that a kill - * did not free up any charges. Everybody else might already - * be sleeping, so restart the fault and keep the rampage - * going until some charges are released. - */ - memcg = current->memcg_oom.wait_on_memcg; if (!memcg) - goto out; + return false; - if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current)) - goto out_memcg; + if (!handle) + goto cleanup; owait.memcg = memcg; owait.wait.flags = 0; @@ -2303,13 +2252,25 @@ bool mem_cgroup_oom_synchronize(void) INIT_LIST_HEAD(&owait.wait.task_list); prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE); - /* Only sleep if we didn't miss any wakeups since OOM */ - if (atomic_read(&memcg->oom_wakeups) == current->memcg_oom.wakeups) + mem_cgroup_mark_under_oom(memcg); + + locked = mem_cgroup_oom_trylock(memcg); + + if (locked) + mem_cgroup_oom_notify(memcg); + + if (locked && !memcg->oom_kill_disable) { + mem_cgroup_unmark_under_oom(memcg); + finish_wait(&memcg_oom_waitq, &owait.wait); + mem_cgroup_out_of_memory(memcg, current->memcg_oom.gfp_mask, + current->memcg_oom.order); + } else { schedule(); - finish_wait(&memcg_oom_waitq, &owait.wait); -out_memcg: - mem_cgroup_unmark_under_oom(memcg); - if (current->memcg_oom.oom_locked) { + mem_cgroup_unmark_under_oom(memcg); + finish_wait(&memcg_oom_waitq, &owait.wait); + } + + if (locked) { mem_cgroup_oom_unlock(memcg); /* * There is no guarantee that an OOM-lock contender @@ -2318,10 +2279,9 @@ out_memcg: */ memcg_oom_recover(memcg); } +cleanup: + current->memcg_oom.memcg = NULL; css_put(&memcg->css); - current->memcg_oom.wait_on_memcg = NULL; -out: - current->memcg_oom.in_memcg_oom = 0; return true; } @@ -2742,6 +2702,9 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm, || fatal_signal_pending(current))) goto bypass; + if (unlikely(task_in_memcg_oom(current))) + goto bypass; + /* * We always charge the cgroup the mm_struct belongs to. * The mm_struct's mem_cgroup changes on task migration if the diff --git a/mm/memory.c b/mm/memory.c index c4ce987745e4..0984f398d746 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3860,15 +3860,21 @@ int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, * space. Kernel faults are handled more gracefully. */ if (flags & FAULT_FLAG_USER) - mem_cgroup_enable_oom(); + mem_cgroup_oom_enable(); ret = __handle_mm_fault(mm, vma, address, flags); - if (flags & FAULT_FLAG_USER) - mem_cgroup_disable_oom(); - - if (WARN_ON(task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM))) - mem_cgroup_oom_synchronize(); + if (flags & FAULT_FLAG_USER) { + mem_cgroup_oom_disable(); + /* + * The task may have entered a memcg OOM situation but + * if the allocation error was handled gracefully (no + * VM_FAULT_OOM), there is no need to kill anything. + * Just clean up the OOM state peacefully. + */ + if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM)) + mem_cgroup_oom_synchronize(false); + } return ret; } diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 1a582e3aee3e..4d87d7c4ed2e 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -704,7 +704,7 @@ void pagefault_out_of_memory(void) { struct zonelist *zonelist; - if (mem_cgroup_oom_synchronize()) + if (mem_cgroup_oom_synchronize(true)) return; zonelist = node_zonelist(first_online_node, GFP_KERNEL); |