From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx171.postini.com [74.125.245.171]) by kanga.kvack.org (Postfix) with SMTP id 8988C6B0044 for ; Wed, 25 Apr 2012 20:20:36 -0400 (EDT) Received: by iajr24 with SMTP id r24so1138464iaj.14 for ; Wed, 25 Apr 2012 17:20:35 -0700 (PDT) Date: Wed, 25 Apr 2012 17:20:32 -0700 (PDT) From: David Rientjes Subject: Re: [RFC] propagate gfp_t to page table alloc functions In-Reply-To: <4F98914C.2060505@jp.fujitsu.com> Message-ID: 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> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: KAMEZAWA Hiroyuki Cc: Andrew Morton , KOSAKI Motohiro , Nick Piggin , Minchan Kim , Ingo Molnar , x86@kernel.org, Hugh Dickins , Johannes Weiner , Rik van Riel , Mel Gorman , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Thu, 26 Apr 2012, KAMEZAWA Hiroyuki wrote: > > Or do we instead do this: > > > > - some_function(foo, bar, GFP_NOIO); > > + old_gfp = set_current_gfp(GFP_NOIO); > > + some_function(foo, bar); > > + set_current_gfp(old_gfp); > > > > So the rule is "if the code was using an explicit GFP_foo then convert > > it to use set_current_gfp(). If the code was receiving a gfp_t > > variable from the caller then delete that arg". > > > > Or something like that. It's all too hopelessly impractical to bother > > discussing - 20 years too late! > > > > > > otoh, maybe a constrained version of this could be used to address the > > vmalloc() problem alone. > > > > Yes, I think it will be good start. > 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). -- 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