Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1281893 > unrolled thread

[PATCH v2] mm, oom: Give __GFP_NOFAIL allocations access to memory reserves

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  [PATCH v2] mm, oom: Give __GFP_NOFAIL allocations access to memory reserves Michal Hocko <mhocko@kernel.org> - 2015-12-02 16:20 +0100
    Re: [PATCH v2] mm, oom: Give __GFP_NOFAIL allocations access to  memory reserves David Rientjes <rientjes@google.com> - 2015-12-03 01:10 +0100

#1281893 — [PATCH v2] mm, oom: Give __GFP_NOFAIL allocations access to memory reserves

From: Michal Hocko <mhocko@suse.com>

__GFP_NOFAIL is a big hammer used to ensure that the allocation
request can never fail. This is a strong requirement and as such
it also deserves a special treatment when the system is OOM. The
primary problem here is that the allocation request might have
come with some locks held and the oom victim might be blocked
on the same locks. This is basically an OOM deadlock situation.

This patch tries to reduce the risk of such a deadlocks by giving
__GFP_NOFAIL allocations a special treatment and let them dive into
memory reserves after oom killer invocation. This should help them
to make a progress and release resources they are holding. The OOM
victim should compensate for the reserves consumption.

Suggested-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
---
 mm/page_alloc.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8034909faad2..367523b2948b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2766,8 +2766,21 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
 			goto out;
 	}
 	/* Exhausted what can be done so it's blamo time */
-	if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL))
+	if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
 		*did_some_progress = 1;
+
+		if (gfp_mask & __GFP_NOFAIL) {
+			page = get_page_from_freelist(gfp_mask, order,
+					ALLOC_NO_WATERMARKS|ALLOC_CPUSET, ac);
+			/*
+			 * fallback to ignore cpuset restriction if our nodes
+			 * are depleted
+			 */
+			if (!page)
+				page = get_page_from_freelist(gfp_mask, order,
+					ALLOC_NO_WATERMARKS, ac);
+		}
+	}
 out:
 	mutex_unlock(&oom_lock);
 	return page;
-- 
2.6.2

--
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/

[toc] | [next] | [standalone]

#1282610 — Re: [PATCH v2] mm, oom: Give __GFP_NOFAIL allocations access to memory reserves

On Wed, 2 Dec 2015, Michal Hocko wrote:

> From: Michal Hocko <mhocko@suse.com>
> 
> __GFP_NOFAIL is a big hammer used to ensure that the allocation
> request can never fail. This is a strong requirement and as such
> it also deserves a special treatment when the system is OOM. The
> primary problem here is that the allocation request might have
> come with some locks held and the oom victim might be blocked
> on the same locks. This is basically an OOM deadlock situation.
> 
> This patch tries to reduce the risk of such a deadlocks by giving
> __GFP_NOFAIL allocations a special treatment and let them dive into
> memory reserves after oom killer invocation. This should help them
> to make a progress and release resources they are holding. The OOM
> victim should compensate for the reserves consumption.
> 
> Suggested-by: Andrea Arcangeli <aarcange@redhat.com>
> Signed-off-by: Michal Hocko <mhocko@suse.com>

Acked-by: David Rientjes <rientjes@google.com>
--
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/

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web