From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: mhocko@kernel.org
Cc: akpm@linux-foundation.org, vbabka@suse.cz, hannes@cmpxchg.org,
mgorman@suse.de, rientjes@google.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] mm, oom: do not enfore OOM killer for __GFP_NOFAIL automatically
Date: Sun, 11 Dec 2016 22:53:55 +0900 [thread overview]
Message-ID: <201612112253.GGH60933.tOMHJQOFSOFFVL@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <201612112023.HBB57332.QOFFtJLOOMFSVH@I-love.SAKURA.ne.jp>
Tetsuo Handa wrote:
> Michal Hocko wrote:
> > On Thu 08-12-16 21:53:44, Tetsuo Handa wrote:
> > > If we could agree
> > > with calling __alloc_pages_nowmark() before out_of_memory() if __GFP_NOFAIL
> > > is given, we can avoid locking up while minimizing possibility of invoking
> > > the OOM killer...
> >
> > I do not understand. We do __alloc_pages_nowmark even when oom is called
> > for GFP_NOFAIL.
>
> Where is that? I can find __alloc_pages_nowmark() after out_of_memory()
> if __GFP_NOFAIL is given, but I can't find __alloc_pages_nowmark() before
> out_of_memory() if __GFP_NOFAIL is given.
>
> What I mean is below patch folded into
> "[PATCH 1/2] mm: consolidate GFP_NOFAIL checks in the allocator slowpath".
>
Oops, I wrongly implemented "__alloc_pages_nowmark() before out_of_memory() if
__GFP_NOFAIL is given." case. Updated version is shown below.
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3116,23 +3116,27 @@ void warn_alloc(gfp_t gfp_mask, const char *fmt, ...)
/* The OOM killer may not free memory on a specific node */
if (gfp_mask & __GFP_THISNODE)
goto out;
+ } else {
+ /*
+ * Help non-failing allocations by giving them access to memory
+ * reserves
+ */
+ 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);
+ if (page)
+ 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))
*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;
@@ -3738,6 +3742,11 @@ bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
*/
WARN_ON_ONCE(order > PAGE_ALLOC_COSTLY_ORDER);
+ /* Try memory reserves and then start killing things. */
+ page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
+ if (page)
+ goto got_pg;
+
cond_resched();
goto retry;
}
I'm calling __alloc_pages_may_oom() from nopage: because we reach without
calling __alloc_pages_may_oom(), for PATCH 1/2 is not for stop enforcing
the OOM killer for __GFP_NOFAIL.
next prev parent reply other threads:[~2016-12-11 13:54 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-01 15:25 [PATCH 0/2] GFP_NOFAIL cleanups Michal Hocko
2016-12-01 15:25 ` [PATCH 1/2] mm: consolidate GFP_NOFAIL checks in the allocator slowpath Michal Hocko
2016-12-01 15:25 ` [PATCH 2/2] mm, oom: do not enfore OOM killer for __GFP_NOFAIL automatically Michal Hocko
2016-12-02 7:23 ` Vlastimil Babka
2016-12-05 13:45 ` Tetsuo Handa
2016-12-05 14:10 ` Michal Hocko
2016-12-06 8:27 ` Michal Hocko
2016-12-06 10:38 ` Tetsuo Handa
2016-12-06 11:03 ` Vlastimil Babka
2016-12-06 19:25 ` Michal Hocko
2016-12-06 19:22 ` Michal Hocko
2016-12-08 12:53 ` Tetsuo Handa
2016-12-08 13:47 ` Michal Hocko
2016-12-11 11:23 ` Tetsuo Handa
2016-12-11 13:53 ` Tetsuo Handa [this message]
2016-12-12 8:52 ` Michal Hocko
2016-12-12 8:48 ` Michal Hocko
2016-12-14 10:34 ` Michal Hocko
2016-12-16 7:39 OOM: Better, but still there on 4.9 Michal Hocko
2016-12-16 15:58 ` OOM: Better, but still there on Michal Hocko
2016-12-16 15:58 ` [PATCH 2/2] mm, oom: do not enfore OOM killer for __GFP_NOFAIL automatically Michal Hocko
2016-12-16 17:31 ` Johannes Weiner
2016-12-16 22:12 ` Michal Hocko
2016-12-17 11:17 ` Tetsuo Handa
2016-12-18 16:37 ` Michal Hocko
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