From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f47.google.com (mail-wm0-f47.google.com [74.125.82.47]) by kanga.kvack.org (Postfix) with ESMTP id B48FA6B0005 for ; Thu, 17 Mar 2016 09:21:41 -0400 (EDT) Received: by mail-wm0-f47.google.com with SMTP id l68so25984655wml.0 for ; Thu, 17 Mar 2016 06:21:41 -0700 (PDT) Received: from mail-wm0-x244.google.com (mail-wm0-x244.google.com. [2a00:1450:400c:c09::244]) by mx.google.com with ESMTPS id p3si10183921wjp.160.2016.03.17.06.21.40 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 17 Mar 2016 06:21:40 -0700 (PDT) Received: by mail-wm0-x244.google.com with SMTP id l124so8969699wmf.2 for ; Thu, 17 Mar 2016 06:21:40 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20160317125736.GT14143@nuc-i3427.alporthouse.com> References: <1458215982-13405-1-git-send-email-chris@chris-wilson.co.uk> <20160317125736.GT14143@nuc-i3427.alporthouse.com> Date: Thu, 17 Mar 2016 14:21:40 +0100 Message-ID: Subject: Re: [PATCH 1/2] mm/vmap: Add a notifier for when we run out of vmap address space From: Roman Peniaev Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Chris Wilson , Roman Peniaev , intel-gfx@lists.freedesktop.org, Andrew Morton , David Rientjes , Mel Gorman , linux-mm@kvack.org, "linux-kernel@vger.kernel.org" On Thu, Mar 17, 2016 at 1:57 PM, Chris Wilson wrote: > On Thu, Mar 17, 2016 at 01:37:06PM +0100, Roman Peniaev wrote: >> > + freed = 0; >> > + blocking_notifier_call_chain(&vmap_notify_list, 0, &freed); >> >> It seems to me that alloc_vmap_area() was designed not to sleep, >> at least on GFP_NOWAIT path (__GFP_DIRECT_RECLAIM is not set). >> >> But blocking_notifier_call_chain() might sleep. > > Indeed, I had not anticipated anybody using GFP_ATOMIC or equivalently > restrictive gfp_t for vmap and yes there are such callers. > > Would guarding the notifier with gfp & __GFP_DIRECT_RECLAIM and > !(gfp & __GFP_NORETRY) == be sufficient? Is that enough for GFP_NOFS? I would use gfpflags_allow_blocking() for that purpose. Roman -- 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/ . Don't email: email@kvack.org