From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH 1/2] r8169: allocate with GFP_KERNEL flag when able to sleep Date: Fri, 08 Oct 2010 17:04:07 +0200 Message-ID: <1286550247.2959.444.camel@edumazet-laptop> References: <1286547901-10782-1-git-send-email-sgruszka@redhat.com> <20101008145256.GB10393@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Francois Romieu , netdev@vger.kernel.org To: Stanislaw Gruszka Return-path: Received: from mail-wy0-f174.google.com ([74.125.82.174]:45249 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758355Ab0JHPER (ORCPT ); Fri, 8 Oct 2010 11:04:17 -0400 Received: by wyb28 with SMTP id 28so1177328wyb.19 for ; Fri, 08 Oct 2010 08:04:15 -0700 (PDT) In-Reply-To: <20101008145256.GB10393@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: Le vendredi 08 octobre 2010 =C3=A0 16:52 +0200, Stanislaw Gruszka a =C3= =A9crit : > On Fri, Oct 08, 2010 at 04:25:00PM +0200, Stanislaw Gruszka wrote: > > We have fedora bug report where driver fail to initialize after > > suspend/resume because of memory allocation errors: > > https://bugzilla.redhat.com/show_bug.cgi?id=3D629158 >=20 > There is also one more thing to do regarding above. Calltraces from b= ug > reports, shows that order 3 allocation fail. On arch with 4kB pages, > order 3 mean 32kB allocation. We want to alloc 16kB, but there is als= o > internal sk_buff data what make that we exceed the boundary and take > 32kB from allocator, getting almost 50% wastage. >=20 Or its only an 1460+overhead allocation, and SLUB uses order-3 pages to satisfy 2048 bytes allocations. # grep 2048 /proc/slabinfo=20 kmalloc-2048 8664 8752 2048 16 8 : tunables 0 0 0 : slabdata 547 547 0 8 in the column just says that : order-3 pages, even for small allocations. Switch to SLAB -> no more problem ;) > To fix we can use similar method as in niu or iwlwifi drivers, alloc > pages directly form buddy allocator and attach them to skb (by > skb_add_rx_frag for example). I'm going to prepare such patch, but > I have one doubt, what happens if page size in system is bigger > than 16kB, should I care about such case?=20 Seems tricky. Should we patch all drivers to do something like that ?