From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: sk_lock: inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage Date: Tue, 14 Jul 2009 09:04:32 -0700 (PDT) Message-ID: <20090714.090432.13343695.davem@davemloft.net> References: <20090709.171355.09466097.davem@davemloft.net> <20090710080017.GA24168@localhost> <20090710080247.GA2693@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Cc: fengguang.wu@intel.com, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, netdev@vger.kernel.org To: herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:54465 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753351AbZGNQE2 (ORCPT ); Tue, 14 Jul 2009 12:04:28 -0400 In-Reply-To: <20090710080247.GA2693-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: From: Herbert Xu Date: Fri, 10 Jul 2009 16:02:47 +0800 > On Fri, Jul 10, 2009 at 04:00:17PM +0800, Wu Fengguang wrote: >> >> The (sk_allocation & ~__GFP_WAIT) cases should be rare, but I guess >> the networking code shall do it anyway, because sk_allocation defaults >> to GFP_KERNEL. It seems that currently the networking code simply uses >> a lot of GFP_ATOMIC, do they really mean "I cannot sleep"? > > Yep because they're done from softirq context. Yes, this is the core issue. All of Wu's talk about how "GFP_ATOMIC will wake up kswapd and therefore can succeed just as well as GFP_KERNEL" is not relevant, because GFP_ATOMIC means sleeping is not allowed.