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[202.181.97.72]) by mx.google.com with ESMTPS id t185si2980784oib.8.2019.03.08.02.22.09 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Mar 2019 02:22:09 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of penguin-kernel@i-love.sakura.ne.jp designates 202.181.97.72 as permitted sender) client-ip=202.181.97.72; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of penguin-kernel@i-love.sakura.ne.jp designates 202.181.97.72 as permitted sender) smtp.mailfrom=penguin-kernel@i-love.sakura.ne.jp Received: from fsav106.sakura.ne.jp (fsav106.sakura.ne.jp [27.133.134.233]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id x28AM2gi001113; Fri, 8 Mar 2019 19:22:02 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav106.sakura.ne.jp (F-Secure/fsigk_smtp/530/fsav106.sakura.ne.jp); Fri, 08 Mar 2019 19:22:02 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/530/fsav106.sakura.ne.jp) Received: from ccsecurity.localdomain (softbank126126163036.bbtec.net [126.126.163.36]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id x28ALwdI001079 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 8 Mar 2019 19:22:02 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) From: Tetsuo Handa To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, Tetsuo Handa Subject: [PATCH] mm,oom: Teach lockdep about oom_lock. Date: Fri, 8 Mar 2019 19:22:02 +0900 Message-Id: <1552040522-9085-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> X-Mailer: git-send-email 1.8.3.1 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Since we are not allowed to depend on blocking memory allocations when oom_lock is already held, teach lockdep to consider that blocking memory allocations might wait for oom_lock at as early location as possible, and teach lockdep to consider that oom_lock is held by mutex_lock() than by mutex_trylock(). Also, since the OOM killer is disabled until the OOM reaper or exit_mmap() sets MMF_OOM_SKIP, teach lockdep to consider that oom_lock is held when __oom_reap_task_mm() is called. This patch should not cause lockdep splats unless there is somebody doing dangerous things (e.g. from OOM notifiers, from the OOM reaper). Signed-off-by: Tetsuo Handa --- mm/oom_kill.c | 9 ++++++++- mm/page_alloc.c | 13 +++++++++++++ 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 3a24848..759aa4e 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -513,6 +513,7 @@ bool __oom_reap_task_mm(struct mm_struct *mm) */ set_bit(MMF_UNSTABLE, &mm->flags); + mutex_acquire(&oom_lock.dep_map, 0, 0, _THIS_IP_); for (vma = mm->mmap ; vma; vma = vma->vm_next) { if (!can_madv_dontneed_vma(vma)) continue; @@ -544,6 +545,7 @@ bool __oom_reap_task_mm(struct mm_struct *mm) tlb_finish_mmu(&tlb, range.start, range.end); } } + mutex_release(&oom_lock.dep_map, 1, _THIS_IP_); return ret; } @@ -1120,8 +1122,13 @@ void pagefault_out_of_memory(void) if (mem_cgroup_oom_synchronize(true)) return; - if (!mutex_trylock(&oom_lock)) + if (!mutex_trylock(&oom_lock)) { + mutex_acquire(&oom_lock.dep_map, 0, 0, _THIS_IP_); + mutex_release(&oom_lock.dep_map, 1, _THIS_IP_); return; + } + mutex_release(&oom_lock.dep_map, 1, _THIS_IP_); + mutex_acquire(&oom_lock.dep_map, 0, 0, _THIS_IP_); out_of_memory(&oc); mutex_unlock(&oom_lock); } diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 6d0fa5b..25533214 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3793,6 +3793,8 @@ void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...) schedule_timeout_uninterruptible(1); return NULL; } + mutex_release(&oom_lock.dep_map, 1, _THIS_IP_); + mutex_acquire(&oom_lock.dep_map, 0, 0, _THIS_IP_); /* * Go through the zonelist yet one more time, keep very high watermark @@ -4651,6 +4653,17 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order, fs_reclaim_acquire(gfp_mask); fs_reclaim_release(gfp_mask); + /* + * Allocation requests which can call __alloc_pages_may_oom() might + * fail to bail out due to waiting for oom_lock. + */ + if ((gfp_mask & __GFP_DIRECT_RECLAIM) && !(gfp_mask & __GFP_NORETRY) && + (!(gfp_mask & __GFP_RETRY_MAYFAIL) || + order <= PAGE_ALLOC_COSTLY_ORDER)) { + mutex_acquire(&oom_lock.dep_map, 0, 0, _THIS_IP_); + mutex_release(&oom_lock.dep_map, 1, _THIS_IP_); + } + might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM); if (should_fail_alloc_page(gfp_mask, order)) -- 1.8.3.1