From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Mason Subject: Re: Root-causing kswapd spinning on Sandy Bridge laptops? Date: Fri, 24 Jun 2011 14:54:11 -0400 Message-ID: <1308941289-sup-5157@shiny> References: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Return-path: In-reply-to: Sender: owner-linux-mm@kvack.org To: Andi Kleen Cc: Andrew Lutomirski , Minchan Kim , linux-mm , intel-gfx List-Id: intel-gfx@lists.freedesktop.org Excerpts from Andi Kleen's message of 2011-06-24 14:44:12 -0400: > Andrew Lutomirski writes: >=20 > [Putting the Intel graphics driver developers in cc.] >=20 > > I'm back :-/ > > > > I just triggered the kswapd bug on 2.6.39.1, which has the > > cond_resched in shrink_slab. This time my system's still usable (I'm > > tying this email on it), but kswapd0 is taking 100% cpu. It *does* > > schedule (tested by setting its affinity the same as another CPU hog > > and confirming that each one gets 50%). > > > > It appears to be calling i915_gem_inactive_shrink in a loop. I have > > probes on entry and return of i915_gem_inactive_shrink and on return > > of shrink_slab. I see: > > > > kswapd0 47 [000] 59599.956573: mm_vmscan_kswapd_wake: nid= =3D0 order=3D0 > > kswapd0 47 [000] 59599.956575: shrink_zone: > > (ffffffff810c848c) priority=3D12 zone=3Dffff8801005fe000 > > kswapd0 47 [000] 59599.956576: shrink_zone_return: > > (ffffffff810c848c <- ffffffff810c96c6) arg1=3D0 > > kswapd0 47 [000] 59599.956578: i915_gem_inactive_shrink: A similar trace came up a bunch of times in Jejb's NMI softlockup/kswapd consumes the machine thread. That one was tracked down to slub high order allocations. I'm sure that one is burned in on Mel's memory, but after a while the individual traces fell out of the thread, and I'm not sure the i915 part stuck out. -chris -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter= .ca/ Don't email: email@kvack.org