linux-kernel - Re: [PATCH v3 2/2] zram: try vmalloc() after kmalloc()

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Date:	Tue, 1 Dec 2015 09:33:47 +0900
From:	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:	Minchan Kim <minchan@...nel.org>
Cc:	"kyeongdon.kim" <kyeongdon.kim@....com>,
	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Subject: Re: [PATCH v3 2/2] zram: try vmalloc() after kmalloc()

On (12/01/15 08:18), Minchan Kim wrote:
[..]
> > As you know, if there is 'null' return, this function is called again to
> > get a memory in while() loop. I just checked this one with printk().
> > 
> > If you guys don't mind, I'll test more with trace log to check time delay.
> 
> No problem.
> 
> > 
> > However, If this is fully expectable status to you.
> > I think I don't need to do it.
> 
> It's not what I expected. Actually, I thought failure of vmalloc
> in that place should be *really really* rare. I think it's caused by
> __GFP_NOMEMALLOC so I want to see test result without the flag.

hm, agree. otherwise the whole vmalloc() fallback thing adds a
little value. additional streams are really not that important
to waste emergency memory. a stream, once allocated, stays
forever (until user decrease the ->max_strm).

> Thanks for the careful test!

yes, thank you Kyeongdon.

	-ss
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