From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752470AbbBBFhN (ORCPT ); Mon, 2 Feb 2015 00:37:13 -0500 Received: from ipmail06.adl2.internode.on.net ([150.101.137.129]:34210 "EHLO ipmail06.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751600AbbBBFhL (ORCPT ); Mon, 2 Feb 2015 00:37:11 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av4WAKQLz1R5LHOVPGdsb2JhbABbgwaBK4Iyg3mrcQEBAQEBAQaYKQICAQECgRZEAQEBAQEGAQEBATg7hAwBAQEEOhwjEAgDFQMJJQ8FJQMHLYgs0wABAQEHAgEfGIVsiRANVwcWhBMFmC2KNYgohCQqMYECAR+BIAEBAQ Date: Mon, 2 Feb 2015 16:37:08 +1100 From: Dave Chinner To: green@linuxhacker.ru Cc: Steven Whitehouse , cluster-devel@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] gfs2: use __vmalloc GFP_NOFS for fs-related allocations. Message-ID: <20150202053708.GG4251@dastard> References: <1422849594-15677-1-git-send-email-green@linuxhacker.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1422849594-15677-1-git-send-email-green@linuxhacker.ru> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Feb 01, 2015 at 10:59:54PM -0500, green@linuxhacker.ru wrote: > From: Oleg Drokin > > leaf_dealloc uses vzalloc as a fallback to kzalloc(GFP_NOFS), so > it clearly does not want any shrinker activity within the fs itself. > convert vzalloc into __vmalloc(GFP_NOFS|__GFP_ZERO) to better achieve > this goal. > > Signed-off-by: Oleg Drokin > --- > fs/gfs2/dir.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c > index c5a34f0..6371192 100644 > --- a/fs/gfs2/dir.c > +++ b/fs/gfs2/dir.c > @@ -1896,7 +1896,8 @@ static int leaf_dealloc(struct gfs2_inode *dip, u32 index, u32 len, > > ht = kzalloc(size, GFP_NOFS | __GFP_NOWARN); > if (ht == NULL) > - ht = vzalloc(size); > + ht = __vmalloc(size, GFP_NOFS | __GFP_NOWARN | __GFP_ZERO, > + PAGE_KERNEL); That, in the end, won't help as vmalloc still uses GFP_KERNEL allocations deep down in the PTE allocation code. See the hacks in the DM and XFS code to work around this. i.e. go look for callers of memalloc_noio_save(). It's ugly and grotesque, but we've got no other way to limit reclaim context because the MM devs won't pass the vmalloc gfp context down the stack to the PTE allocations.... Cheers, Dave. -- Dave Chinner david@fromorbit.com