Re: [Intel-gfx] linux-next: build failure after merge of the tip tree (from the drm-intel tree)

2016-07-05 Thread Paul E. McKenney
On Tue, Jul 05, 2016 at 10:25:12AM +0200, Peter Zijlstra wrote: > On Tue, Jul 05, 2016 at 01:53:03PM +1000, Stephen Rothwell wrote: > > diff --git a/drivers/gpu/drm/i915/i915_gem.c > > b/drivers/gpu/drm/i915/i915_gem.c > > index d3502c0603e5..1f91f187b2a8 100644 > > --- a/drivers/gpu/drm/i915/i915

Re: [Intel-gfx] [PATCH 1/2] Revert "drm/fb-helper: Reduce READ_ONCE(master) to lockless_dereference"

2016-08-11 Thread Paul E. McKenney
On Thu, Aug 11, 2016 at 12:38:59PM +0200, Daniel Vetter wrote: > On Thu, Aug 11, 2016 at 11:50:21AM +0200, Johannes Berg wrote: > > From: Johannes Berg > > > > This reverts commit fa7d81bb3c269a2ee38b6e4d569d9eb8be1a78ad. > > > > As Peter explained: > > [...] lockless_dereference() is _stronge

Re: [Intel-gfx] drm/fb-helper: Reduce READ_ONCE(master) to lockless_dereference

2016-08-11 Thread Paul E. McKenney
On Thu, Aug 11, 2016 at 11:44:08AM +0200, Peter Zijlstra wrote: > On Wed, Jun 22, 2016 at 08:46:12AM +0100, Chris Wilson wrote: > > We are only documenting that the read is outside of the lock, and do not > > require strict ordering on the operation. In this case the more relaxed > > lockless_deref

Re: [Intel-gfx] [PATCH 1/2] Revert "drm/fb-helper: Reduce READ_ONCE(master) to lockless_dereference"

2016-08-12 Thread Paul E. McKenney
On Fri, Aug 12, 2016 at 08:25:43PM +0200, Peter Zijlstra wrote: > On Thu, Aug 11, 2016 at 11:26:47AM -0700, Paul E. McKenney wrote: > > If my upcoming testing of the two changes together pans out, I will > > give you a Tested-by -- I am guessing that you don't want to wait >

Re: [Intel-gfx] [PATCH v2 1/3] drm/i915: Enable lockless lookup of request tracking via RCU

2016-01-06 Thread Paul E. McKenney
On Wed, Jan 06, 2016 at 09:38:30AM +0100, Peter Zijlstra wrote: > On Wed, Jan 06, 2016 at 09:06:58AM +0100, Daniel Vetter wrote: > > This pretty much went over my head ;-) What I naively hoped for is that > > kfree() on an rcu-freeing slab could be tought to magically stall a bit > > (or at least e

Re: [Intel-gfx] [PATCH v2 1/3] drm/i915: Enable lockless lookup of request tracking via RCU

2016-01-06 Thread Paul E. McKenney
On Tue, Jan 05, 2016 at 04:06:48PM +0100, Peter Zijlstra wrote: > On Tue, Jan 05, 2016 at 04:02:13PM +0100, Peter Zijlstra wrote: > > > Shouldn't the slab subsystem do this for us if we request it delays the > > > actual kfree? Seems like a core bug to me ... Adding more folks. > > > > note that s

Re: [Intel-gfx] linux-next: build failure after merge of the rcu tree

2017-03-08 Thread Paul E. McKenney
On Wed, Mar 08, 2017 at 11:13:38AM +0100, Daniel Vetter wrote: > On Wed, Mar 08, 2017 at 12:16:45PM +1100, Stephen Rothwell wrote: > > Hi Paul, > > > > After merging the rcu tree, today's linux-next build (x86_64 allmodconfig) > > failed like this: > > > > In file included from include/linux/reso

Re: [Intel-gfx] [BUG?] INFO: rcu_sched detected expedited stalls on CPUs/tasks: { 0-.... } 3 jiffies s: 309 root: 0x1/.

2023-04-21 Thread Paul E. McKenney
On Thu, Apr 13, 2023 at 04:32:32PM +0100, Rui Salvaterra wrote: > Hi, Paul, > > On Thu, 13 Apr 2023 at 15:43, Paul E. McKenney wrote: > > > > My guess would be that you have CONFIG_RCU_EXP_CPU_STALL_TIMEOUT set to > > some small non-zero number, for example, you

Re: [Intel-gfx] [BUG?] INFO: rcu_sched detected expedited stalls on CPUs/tasks: { 0-.... } 3 jiffies s: 309 root: 0x1/.

2023-04-21 Thread Paul E. McKenney
On Thu, Apr 13, 2023 at 08:30:02AM +0100, Rui Salvaterra wrote: > Hi again, everyone. > > So, while preparing to file the bug report with the requested > information, I got a trace completely unrelated to DRM (on a swapon > call, it seems). > > [4.868340] rcu: INFO: rcu_sched detected expedit

Re: [Intel-gfx] [PATCH 24/29] mm: vmscan: make global slab shrink lockless

2023-07-06 Thread Paul E. McKenney
On Fri, Jun 23, 2023 at 04:29:39PM +1000, Dave Chinner wrote: > On Thu, Jun 22, 2023 at 05:12:02PM +0200, Vlastimil Babka wrote: > > On 6/22/23 10:53, Qi Zheng wrote: > > > @@ -1067,33 +1068,27 @@ static unsigned long shrink_slab(gfp_t gfp_mask, > > > int nid, > > > if (!mem_cgroup_disabled() &&

Re: [Intel-gfx] [PATCH tip/core/rcu 11/15] drm/i915: Cleanup PREEMPT_COUNT leftovers

2020-10-01 Thread Paul E. McKenney
On Thu, Oct 01, 2020 at 10:25:06AM +0200, Thomas Gleixner wrote: > On Thu, Oct 01 2020 at 10:17, Joonas Lahtinen wrote: > > Quoting paul...@kernel.org (2020-09-29 02:30:58) > >> CONFIG_PREEMPT_COUNT is now unconditionally enabled and will be > >> removed. Cleanup the leftovers before doing so. > >

Re: [Intel-gfx] [PATCH 04/65] mm: Extract might_alloc() debug check

2020-10-23 Thread Paul E. McKenney
> equivalent for GFP_NOWAIT, hence this check can't go wrong due to > memalloc_no*_save/restore contexts. > > Cc: Paul E. McKenney > Cc: Christoph Lameter > Cc: Pekka Enberg > Cc: David Rientjes > Cc: Joonsoo Kim > Cc: Andrew Morton > Cc: Peter Zijlstra &g

Re: [Intel-gfx] [PATCH tip/core/rcu 03/10] drivers/gpu: Replace rcu_swap_protected() with rcu_replace()

2019-10-28 Thread Paul E. McKenney
On Mon, Oct 28, 2019 at 02:57:26PM +0200, Joonas Lahtinen wrote: > Quoting paul...@kernel.org (2019-10-22 22:12:08) > > From: "Paul E. McKenney" > > > > This commit replaces the use of rcu_swap_protected() with the more > > intuitively appealing rcu

Re: [Intel-gfx] rcu_barrier() no longer allowed within mmap_sem?

2020-03-30 Thread Paul E. McKenney
On Mon, Mar 30, 2020 at 03:00:35PM +0200, Daniel Vetter wrote: > Hi all, for all = rcu, cpuhotplug and perf maintainers > > We've hit an interesting new lockdep splat in our drm/i915 CI: > > https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17096/shard-tglb7/igt@kms_frontbuffer_track...@fbcpsr-r

Re: [Intel-gfx] [patch 00/13] preempt: Make preempt count unconditional

2020-09-15 Thread Paul E. McKenney
On Mon, Sep 14, 2020 at 01:59:15PM -0700, Linus Torvalds wrote: > On Mon, Sep 14, 2020 at 1:45 PM Thomas Gleixner wrote: > > > > Recently merged code does: > > > > gfp = preemptible() ? GFP_KERNEL : GFP_ATOMIC; > > > > Looks obviously correct, except for the fact that preemptible() is > >

Re: [Intel-gfx] [patch 00/13] preempt: Make preempt count unconditional

2020-09-16 Thread Paul E. McKenney
On Wed, Sep 16, 2020 at 08:23:52PM +0100, Matthew Wilcox wrote: > On Mon, Sep 14, 2020 at 11:55:24PM +0200, Thomas Gleixner wrote: > > But just look at any check which uses preemptible(), especially those > > which check !preemptible(): > > hmm. > > +++ b/include/linux/preempt.h > @@ -180,7 +180,

Re: [Intel-gfx] [patch 00/13] preempt: Make preempt count unconditional

2020-09-16 Thread Paul E. McKenney
On Wed, Sep 16, 2020 at 09:37:17AM +0200, Daniel Vetter wrote: > On Tue, Sep 15, 2020 at 7:35 PM Linus Torvalds > wrote: > > > > On Tue, Sep 15, 2020 at 1:39 AM Thomas Gleixner wrote: > > > > > > OTOH, having a working 'preemptible()' or maybe better named > > > 'can_schedule()' check makes tons

Re: [Intel-gfx] [patch 00/13] preempt: Make preempt count unconditional

2020-09-16 Thread Paul E. McKenney
On Wed, Sep 16, 2020 at 11:32:00AM -0700, Linus Torvalds wrote: > On Wed, Sep 16, 2020 at 8:29 AM Paul E. McKenney wrote: > > > > All fair, but some of us need to write code that must handle being > > invoked from a wide variety of contexts. > > Note that I think

Re: [Intel-gfx] [patch 00/13] preempt: Make preempt count unconditional

2020-09-16 Thread Paul E. McKenney
On Wed, Sep 16, 2020 at 10:29:06PM +0200, Daniel Vetter wrote: > On Wed, Sep 16, 2020 at 5:29 PM Paul E. McKenney wrote: > > > > On Wed, Sep 16, 2020 at 09:37:17AM +0200, Daniel Vetter wrote: > > > On Tue, Sep 15, 2020 at 7:35 PM Linus Torvalds > > > wrote: >

Re: [Intel-gfx] [patch 00/13] preempt: Make preempt count unconditional

2020-09-18 Thread Paul E. McKenney
On Wed, Sep 16, 2020 at 11:43:02PM +0200, Daniel Vetter wrote: > On Wed, Sep 16, 2020 at 10:58 PM Paul E. McKenney wrote: > > > > On Wed, Sep 16, 2020 at 10:29:06PM +0200, Daniel Vetter wrote: > > > On Wed, Sep 16, 2020 at 5:29 PM Paul E. McKenney > > > wrot

Re: [Intel-gfx] [patch 00/13] preempt: Make preempt count unconditional

2020-09-18 Thread Paul E. McKenney
On Thu, Sep 17, 2020 at 09:52:30AM +0200, Daniel Vetter wrote: > On Thu, Sep 17, 2020 at 12:39 AM Paul E. McKenney wrote: > > > > On Wed, Sep 16, 2020 at 11:43:02PM +0200, Daniel Vetter wrote: > > > On Wed, Sep 16, 2020 at 10:58 PM Paul E. McKenney > > > wrot

Re: [Intel-gfx] [PATCH] list: Prevent compiler reloads inside 'safe' list iteration

2020-03-10 Thread Paul E. McKenney
On Tue, Mar 10, 2020 at 03:05:57PM +, David Laight wrote: > From: Marco Elver > > Sent: 10 March 2020 14:10 > ... > > FWIW, for writes we're already being quite generous, in that plain > > aligned writes up to word-size are assumed to be "atomic" with the > > default (conservative) config, i.e.

Re: [Intel-gfx] [PATCH] list: Prevent compiler reloads inside 'safe' list iteration

2020-03-10 Thread Paul E. McKenney
On Tue, Mar 10, 2020 at 12:23:34PM +, David Laight wrote: > From: Chris Wilson > > Sent: 10 March 2020 11:50 > > > > Quoting David Laight (2020-03-10 11:36:41) > > > From: Chris Wilson > > > > Sent: 10 March 2020 09:21 > > > > Instruct the compiler to read the next element in the list iteratio

[Intel-gfx] [tip: core/rcu] drm/i915: Replace rcu_swap_protected() with rcu_replace_pointer()

2019-10-31 Thread tip-bot2 for Paul E. McKenney
The following commit has been merged into the core/rcu branch of tip: Commit-ID: 1feace5d6a4a1acf44dde2bfb5c36cc0b1cf559c Gitweb: https://git.kernel.org/tip/1feace5d6a4a1acf44dde2bfb5c36cc0b1cf559c Author:Paul E. McKenney AuthorDate:Mon, 23 Sep 2019 15:22:15 -07:00