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From: David Rientjes <rientjes@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Thelen <gthelen@google.com>,
	Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
	Davidlohr Bueso <dave@stgolabs.net>,
	"Kirill A. Shutemov" <kirill@shutemov.name>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: [patch v3] mm, hugetlb: abort __get_user_pages if current has been oom killed
Date: Mon, 9 Mar 2015 13:07:39 -0700 (PDT)	[thread overview]
Message-ID: <alpine.DEB.2.10.1503091307130.10307@chino.kir.corp.google.com> (raw)
In-Reply-To: <xr93r3synzqu.fsf@gthelen.mtv.corp.google.com>

If __get_user_pages() is faulting a significant number of hugetlb pages,
usually as the result of mmap(MAP_LOCKED), it can potentially allocate a
very large amount of memory.

If the process has been oom killed, this will cause a lot of memory to
potentially deplete memory reserves.

In the same way that commit 4779280d1ea4 ("mm: make get_user_pages() 
interruptible") aborted for pending SIGKILLs when faulting non-hugetlb
memory, based on the premise of commit 462e00cc7151 ("oom: stop
allocating user memory if TIF_MEMDIE is set"), hugetlb page faults now
terminate when the process has been oom killed.

Cc: Greg Thelen <gthelen@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: David Rientjes <rientjes@google.com>
---
 v3: tweak changelog per Greg

 mm/hugetlb.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3276,6 +3276,15 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
 		struct page *page;
 
 		/*
+		 * If we have a pending SIGKILL, don't keep faulting pages and
+		 * potentially allocating memory.
+		 */
+		if (unlikely(fatal_signal_pending(current))) {
+			remainder = 0;
+			break;
+		}
+
+		/*
 		 * Some archs (sparc64, sh*) have multiple pte_ts to
 		 * each hugepage.  We have to make sure we get the
 		 * first, for the page indexing below to work.

  reply	other threads:[~2015-03-09 20:07 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-08 23:12 [patch] " David Rientjes
2015-03-09  4:30 ` Kirill A. Shutemov
2015-03-09  7:42   ` [patch v2] " David Rientjes
2015-03-09 11:24     ` Kirill A. Shutemov
2015-03-09 12:04     ` Greg Thelen
2015-03-09 20:07       ` David Rientjes [this message]
2015-03-09 20:53         ` [patch v3] " Rik van Riel
2015-03-10  0:47         ` Greg Thelen
2015-03-10 19:26         ` Davidlohr Bueso

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