From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx110.postini.com [74.125.245.110]) by kanga.kvack.org (Postfix) with SMTP id D75D76B0044 for ; Tue, 24 Apr 2012 17:30:17 -0400 (EDT) Date: Tue, 24 Apr 2012 14:30:15 -0700 From: Andrew Morton Subject: Re: [RFC] propagate gfp_t to page table alloc functions Message-Id: <20120424143015.99fd8d4a.akpm@linux-foundation.org> In-Reply-To: References: <1335171318-4838-1-git-send-email-minchan@kernel.org> <4F963742.2030607@jp.fujitsu.com> <4F963B8E.9030105@kernel.org> <4F965413.9010305@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Nick Piggin Cc: Minchan Kim , KAMEZAWA Hiroyuki , Ingo Molnar , x86@kernel.org, Hugh Dickins , Johannes Weiner , Rik van Riel , Mel Gorman , kosaki.motohiro@jp.fujitsu.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org On Tue, 24 Apr 2012 17:48:29 +1000 Nick Piggin wrote: > > Hmm, there are several places to use GFP_NOIO and GFP_NOFS even, GFP_ATOMIC. > > I believe it's not trivial now. > > They're all buggy then. Unfortunately not through any real fault of their own. There are gruesome problems in block/blk-throttle.c (thread "mempool, percpu, blkcg: fix percpu stat allocation and remove stats_lock"). It wants to do an alloc_percpu()->vmalloc() from the IO submission path, under GFP_NOIO. Changing vmalloc() to take a gfp_t does make lots of sense, although I worry a bit about making vmalloc() easier to use! I do wonder whether the whole scheme of explicitly passing a gfp_t was a mistake and that the allocation context should be part of the task context. ie: pass the allocation mode via *current. As a handy side-effect that would probably save quite some code where functions are receiving a gfp_t arg then simply passing it on to the next callee. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org