Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758104Ab3GYW0t (ORCPT ); Thu, 25 Jul 2013 18:26:49 -0400 Received: from zene.cmpxchg.org ([85.214.230.12]:50990 "EHLO zene.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757419Ab3GYW0D (ORCPT ); Thu, 25 Jul 2013 18:26:03 -0400 From: Johannes Weiner To: Andrew Morton Cc: Michal Hocko , David Rientjes , KAMEZAWA Hiroyuki , azurIt , linux-mm@kvack.org, cgroups@vger.kernel.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [patch 5/6] mm: memcg: enable memcg OOM killer only for user faults Date: Thu, 25 Jul 2013 18:25:37 -0400 Message-Id: <1374791138-15665-6-git-send-email-hannes@cmpxchg.org> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1374791138-15665-1-git-send-email-hannes@cmpxchg.org> References: <1374791138-15665-1-git-send-email-hannes@cmpxchg.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6300 Lines: 195 System calls and kernel faults (uaccess, gup) can handle an out of memory situation gracefully and just return -ENOMEM. Enable the memcg OOM killer only for user faults, where it's really the only option available. Signed-off-by: Johannes Weiner --- include/linux/memcontrol.h | 23 +++++++++++++++++++++++ include/linux/sched.h | 3 +++ mm/filemap.c | 11 ++++++++++- mm/memcontrol.c | 2 +- mm/memory.c | 40 ++++++++++++++++++++++++++++++---------- 5 files changed, 67 insertions(+), 12 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 7b4d9d7..9bb5eeb 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -125,6 +125,24 @@ 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_xchg_may_oom - toggle the memcg OOM killer for a task + * @p: 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. + */ +static inline bool mem_cgroup_xchg_may_oom(struct task_struct *p, bool new) +{ + bool old; + + old = p->memcg_oom.may_oom; + p->memcg_oom.may_oom = new; + + return old; +} + #ifdef CONFIG_MEMCG_SWAP extern int do_swap_account; #endif @@ -348,6 +366,11 @@ static inline void mem_cgroup_end_update_page_stat(struct page *page, { } +static inline bool mem_cgroup_xchg_may_oom(struct task_struct *p, bool new) +{ + return !new; +} + static inline void mem_cgroup_inc_page_stat(struct page *page, enum mem_cgroup_page_stat_item idx) { diff --git a/include/linux/sched.h b/include/linux/sched.h index fc09d21..4b3effc 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1398,6 +1398,9 @@ struct task_struct { unsigned long memsw_nr_pages; /* uncharged mem+swap usage */ } memcg_batch; unsigned int memcg_kmem_skip_account; + struct memcg_oom_info { + unsigned int may_oom:1; + } memcg_oom; #endif #ifdef CONFIG_UPROBES struct uprobe_task *utask; diff --git a/mm/filemap.c b/mm/filemap.c index a6981fe..2932810 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1617,6 +1617,7 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) struct file_ra_state *ra = &file->f_ra; struct inode *inode = mapping->host; pgoff_t offset = vmf->pgoff; + unsigned int may_oom; struct page *page; pgoff_t size; int ret = 0; @@ -1626,7 +1627,11 @@ 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? + * 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. */ page = find_get_page(mapping, offset); if (likely(page) && !(vmf->flags & FAULT_FLAG_TRIED)) { @@ -1634,10 +1639,14 @@ 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. */ + may_oom = mem_cgroup_xchg_may_oom(current, 0); do_async_mmap_readahead(vma, ra, file, page, offset); + mem_cgroup_xchg_may_oom(current, may_oom); } else if (!page) { /* No page in the page cache at all */ + may_oom = mem_cgroup_xchg_may_oom(current, 0); do_sync_mmap_readahead(vma, ra, file, offset); + mem_cgroup_xchg_may_oom(current, may_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 00a7a66..30ae46a 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2614,7 +2614,7 @@ static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, return CHARGE_RETRY; /* If we don't need to call oom-killer at el, return immediately */ - if (!oom_check) + if (!oom_check || !current->memcg_oom.may_oom) return CHARGE_NOMEM; /* check OOM */ if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask, get_order(csize))) diff --git a/mm/memory.c b/mm/memory.c index f2ab2a8..5ea7b47 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3752,22 +3752,14 @@ unlock: /* * By the time we get here, we already hold the mm semaphore */ -int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long address, unsigned int flags) +static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long address, unsigned int flags) { pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t *pte; - __set_current_state(TASK_RUNNING); - - count_vm_event(PGFAULT); - mem_cgroup_count_vm_event(mm, PGFAULT); - - /* do counter updates before entering really critical section. */ - check_sync_rss_stat(current); - if (unlikely(is_vm_hugetlb_page(vma))) return hugetlb_fault(mm, vma, address, flags); @@ -3851,6 +3843,34 @@ retry: return handle_pte_fault(mm, vma, address, pte, pmd, flags); } +int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long address, unsigned int flags) +{ + int ret; + + __set_current_state(TASK_RUNNING); + + count_vm_event(PGFAULT); + mem_cgroup_count_vm_event(mm, PGFAULT); + + /* do counter updates before entering really critical section. */ + check_sync_rss_stat(current); + + /* + * Enable the memcg OOM handling for faults triggered in user + * space. Kernel faults are handled more gracefully. + */ + if (flags & FAULT_FLAG_USER) + WARN_ON(mem_cgroup_xchg_may_oom(current, true) == true); + + ret = __handle_mm_fault(mm, vma, address, flags); + + if (flags & FAULT_FLAG_USER) + WARN_ON(mem_cgroup_xchg_may_oom(current, false) == false); + + return ret; +} + #ifndef __PAGETABLE_PUD_FOLDED /* * Allocate page upper directory. -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/