From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx156.postini.com [74.125.245.156]) by kanga.kvack.org (Postfix) with SMTP id 8066B6B0044 for ; Sun, 29 Apr 2012 21:25:38 -0400 (EDT) Message-ID: <4F9DEA0C.8040203@kernel.org> Date: Mon, 30 Apr 2012 10:25:32 +0900 From: Minchan Kim MIME-Version: 1.0 Subject: Re: [RFC] propagate gfp_t to page table alloc functions References: <1335171318-4838-1-git-send-email-minchan@kernel.org> <4F963742.2030607@jp.fujitsu.com> <4F963B8E.9030105@kernel.org> <4F965413.9010305@kernel.org> <20120424143015.99fd8d4a.akpm@linux-foundation.org> <4F973BF2.4080406@jp.fujitsu.com> <4F973FB8.6050103@jp.fujitsu.com> <20120424172554.c9c330dd.akpm@linux-foundation.org> <4F98914C.2060505@jp.fujitsu.com> <4F9A0360.3030900@kernel.org> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: KAMEZAWA Hiroyuki , Andrew Morton , KOSAKI Motohiro , Nick Piggin , Ingo Molnar , x86@kernel.org, Hugh Dickins , Johannes Weiner , Rik van Riel , Mel Gorman , linux-kernel@vger.kernel.org, linux-mm@kvack.org On 04/27/2012 07:43 PM, David Rientjes wrote: > On Fri, 27 Apr 2012, Minchan Kim wrote: > >>> Maybe a per-thread_info variant of gfp_allowed_mask? So Andrew's >>> set_current_gfp() becomes set_current_gfp_allowed() that does >>> >>> void set_current_gfp_allowed(gfp_t gfp_mask) >>> { >>> current->gfp_allowed = gfp_mask & gfp_allowed_mask; >>> } >>> >>> and then the page allocator does >>> >>> gfp_mask &= current->gfp_allowed; >>> >>> rather than how it currently does >>> >>> gfp_mask &= gfp_allowed_mask; >>> >>> and then the caller of set_current_gfp_allowed() cleans up with >>> set_current_gfp_allowed(__GFP_BITS_MASK). >> > > [trimmed the newsgroups from the reply, not sure what the point is?] > >> Caller should restore old gfp_mask instead of __GFP_BITS_MASK in case of >> nesting.And how do we care of atomic context? >> > > Eek, I'm hoping these aren't going to be nested but sure that seems > appropraite if they are. (I'm also hoping these will only be either > __GFP_HIGH or __GFP_BITS_MASK and no other combinations.) > > Forcing atomic context would just be set_current_gfp_allowed(__GFP_HIGH). I mean it's not legal to access _current_ in atomic context so that (gfp_mask &= current->gfp_allowed in page allocator) shouldn't. -- Kind regards, Minchan Kim -- 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