From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH 06/33] mm: allow PF_MEMALLOC from softirq context Date: Wed, 31 Oct 2007 11:42:39 +0100 Message-ID: <1193827359.27652.129.camel@twins> References: <20071030160401.296770000@chello.nl> <20071030160911.540148000@chello.nl> <200710311451.56747.nickpiggin@yahoo.com.au> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-r7nMOlku9KeVdHIURXUD" Cc: Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, trond.myklebust@fys.uio.no To: Nick Piggin Return-path: Received: from viefep18-int.chello.at ([213.46.255.22]:64286 "EHLO viefep15-int.chello.at" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755547AbXJaKms (ORCPT ); Wed, 31 Oct 2007 06:42:48 -0400 In-Reply-To: <200710311451.56747.nickpiggin@yahoo.com.au> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org --=-r7nMOlku9KeVdHIURXUD Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Wed, 2007-10-31 at 14:51 +1100, Nick Piggin wrote: > On Wednesday 31 October 2007 03:04, Peter Zijlstra wrote: > > Allow PF_MEMALLOC to be set in softirq context. When running softirqs f= rom > > a borrowed context save current->flags, ksoftirqd will have its own > > task_struct. >=20 >=20 > What's this for? Why would ksoftirqd pick up PF_MEMALLOC? (I guess > that some networking thing must be picking it up in a subsequent patch, > but I'm too lazy to look!)... Again, can you have more of a rationale in > your patch headers, or ref the patch that uses it... thanks Right, I knew I was forgetting something in these changelogs. The network stack does quite a bit of packet processing from softirq context. Once you start swapping over network, some of the packets want to be processed under PF_MEMALLOC. See patch 23/33. --=-r7nMOlku9KeVdHIURXUD Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQBHKFwfXA2jU0ANEf4RAkgXAJ98pKdDwE2bTcSNPFtXgN9xp6eTXwCdFhg/ ATCE0SfG+kL0D0HkFDOIv3A= =xQNH -----END PGP SIGNATURE----- --=-r7nMOlku9KeVdHIURXUD--