Date: Sat, 21 Nov 2015 11:15:43 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Kyeongdon Kim <kyeongdon.kim@lge.com>
Cc: minchan@kernel.org, akpm@linux-foundation.org, ngupta@vflare.org,
        linux-kernel@vger.kernel.org, sergey.senozhatsky@gmail.com,
        sergey.senozhatsky.work@gmail.com
Subject: Re: [PATCH v2] zram: Prevent page allocation failure during
 zcomp_strm_alloc
Message-ID: <20151121021542.GB3121@swordfish>
References: <1448013764-21899-1-git-send-email-kyeongdon.kim@lge.com>
 <20151121021059.GA3121@swordfish>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20151121021059.GA3121@swordfish>
User-Agent: Mutt/1.5.24 (2015-08-30)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1317
Lines: 31

On (11/21/15 11:10), Sergey Senozhatsky wrote:
> Cc Andrew
> 
> On (11/20/15 19:02), Kyeongdon Kim wrote:
> > When we're using LZ4 multi compression streams for zram swap,
> > we found out page allocation failure message in system running test.
> > That was not only once, but a few(2 - 5 times per test).
> > Also, some failure cases were continually occurring to try allocation
> > order 3.
> > 
> > In order to make parallel compression private data, we should call
> > kzalloc() with order 2/3 in runtime(lzo/lz4). But if there is no order
> >  2/3 size memory in that time, page allocation fails.
> > This patch makes to use vmalloc() as fallback of kmalloc(), this
> > prevents page alloc failure warning.
> > 
> > After this, we never found warning message in running test, also
> > It could reduce process startup latency about 60-120ms in each case.
> 
> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> 

with the only nit that the subject should be "try kmalloc() before vmalloc()"
or similar, not "prevent page allocation failure", I think.

	-ss
--
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/