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From: Matthew Wilcox <willy@infradead.org>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-mm <linux-mm@kvack.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>,
	Vladimir Davydov <vdavydov.dev@gmail.com>
Subject: Re: [PATCH] mm:memcg: add __GFP_NOWARN in __memcg_schedule_kmem_cache_create
Date: Tue, 17 Apr 2018 20:08:24 -0700	[thread overview]
Message-ID: <20180418030824.GA7320@bombadil.infradead.org> (raw)
In-Reply-To: <20180418022912.248417-1-minchan@kernel.org>

On Wed, Apr 18, 2018 at 11:29:12AM +0900, Minchan Kim wrote:
> If there are heavy memory pressure, page allocation with __GFP_NOWAIT
> fails easily although it's order-0 request.
> I got below warning 9 times for normal boot.
> 
> [   17.072747] c0 0      <snip >: page allocation failure: order:0, mode:0x2200000(GFP_NOWAIT|__GFP_NOTRACK)
> 
> Let's not make user scared.
>  
> -	cw = kmalloc(sizeof(*cw), GFP_NOWAIT);
> +	cw = kmalloc(sizeof(*cw), GFP_NOWAIT | __GFP_NOWARN);
>  	if (!cw)

Not arguing against this patch.  But how many places do we want to use
GFP_NOWAIT without __GFP_NOWARN?  Not many, and the few which do do this
seem like they simply haven't added it yet.  Maybe this would be a good idea?

-#define GFP_NOWAIT      (__GFP_KSWAPD_RECLAIM)
+#define GFP_NOWAIT      (__GFP_KSWAPD_RECLAIM | __GFP_NOWARN)

  parent reply	other threads:[~2018-04-18  3:08 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-18  2:29 Minchan Kim
2018-04-18  2:56 ` David Rientjes
2018-04-18  3:08 ` Matthew Wilcox [this message]
2018-04-18  4:16   ` David Rientjes
2018-04-18  7:09   ` Michal Hocko
2018-04-18  7:20 ` Michal Hocko
2018-04-18  7:41   ` Minchan Kim
2018-04-18  7:54     ` Michal Hocko
2018-04-18 13:23       ` Minchan Kim
2018-04-18 13:27         ` Michal Hocko
2018-04-18 18:58           ` David Rientjes
2018-04-19  6:40             ` Michal Hocko
2018-04-20  5:42               ` Minchan Kim
2018-04-20  8:09                 ` Michal Hocko
2018-04-18 13:31 ` Matthew Wilcox
2018-04-18 13:39   ` Michal Hocko
2018-04-18 19:05 ` Johannes Weiner

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