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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Changli Gao <xiaosuo@gmail.com>
Cc: kosaki.motohiro@jp.fujitsu.com, akpm@linux-foundation.org,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Jiri Slaby <jslaby@suse.cz>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Ingo Molnar <mingo@elte.hu>,
	Peter Zijlstra <peterz@infradead.org>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	Avi Kivity <avi@redhat.com>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Subject: Re: [RFC] mm: generic adaptive large memory allocation APIs
Date: Thu, 13 May 2010 13:45:35 +0900 (JST)	[thread overview]
Message-ID: <20100513134124.2164.A69D9226@jp.fujitsu.com> (raw)
In-Reply-To: <1273105838-4441-1-git-send-email-xiaosuo@gmail.com>

Hi

> void *kvmalloc(size_t size)
> {
> 	void *ptr;
> 
> 	if (size < PAGE_SIZE)
> 		return kmalloc(PAGE_SIZE, GFP_KERNEL);
> 	ptr = alloc_pages_exact(size, GFP_KERNEL | __GFP_NOWARN);

low order GFP_KERNEL allocation never fail. then, this doesn't works
as you expected.

> 	if (ptr != NULL)
> 		return ptr;
> 
> 	return vmalloc(size);

On x86, vmalloc area is only 128MB address space. it is very rare 
resource than physical ram. vmalloc fallback is not good idea.



  parent reply	other threads:[~2010-05-13  4:45 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-06  0:30 Changli Gao
2010-05-06  0:37 ` Changli Gao
2010-05-06  1:25 ` Changli Gao
2010-05-06  3:12 ` Tetsuo Handa
2010-05-06  3:22   ` Changli Gao
2010-05-06 15:35 ` Jamie Lokier
2010-05-07  4:32 ` Changli Gao
2010-05-07 12:42   ` Tetsuo Handa
2010-05-07 12:52     ` Peter Zijlstra
2010-05-13  4:45 ` KOSAKI Motohiro [this message]
2010-05-13  8:43   ` Jiri Slaby
2010-05-13  9:05     ` KOSAKI Motohiro
2010-05-13  9:19       ` Jiri Slaby
2010-05-13  9:40         ` KOSAKI Motohiro
2010-05-13 10:16           ` Jiri Slaby
2010-05-13 10:43             ` KOSAKI Motohiro

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