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2015-09-13sched/fair: Initialize task load and utilization before placing task on rqMorten Rasmussen1-2/+2
Task load or utilization is not currently considered in select_task_rq_fair(), but if we want that in the future we should make sure it is not zero for new tasks. cc: Ingo Molnar <mingo@redhat.com> cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Dietmar Eggemann <Dietmar.Eggemann@arm.com> Cc: Juri Lelli <Juri.Lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: daniel.lezcano@linaro.org Cc: mturquette@baylibre.com Cc: pang.xunlei@zte.com.cn Cc: rjw@rjwysocki.net Cc: sgurrappadi@nvidia.com Cc: vincent.guittot@linaro.org Cc: yuyang.du@intel.com Link: http://lkml.kernel.org/r/1439569394-11974-7-git-send-email-morten.rasmussen@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/fair: Get rid of scaling utilization by capacity_origDietmar Eggemann1-16/+22
Utilization is currently scaled by capacity_orig, but since we now have frequency and cpu invariant cfs_rq.avg.util_avg, frequency and cpu scaling now happens as part of the utilization tracking itself. So cfs_rq.avg.util_avg should no longer be scaled in cpu_util(). Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Juri Lelli <Juri.Lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steve Muckle <steve.muckle@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: daniel.lezcano@linaro.org <daniel.lezcano@linaro.org> Cc: mturquette@baylibre.com <mturquette@baylibre.com> Cc: pang.xunlei@zte.com.cn <pang.xunlei@zte.com.cn> Cc: rjw@rjwysocki.net <rjw@rjwysocki.net> Cc: sgurrappadi@nvidia.com <sgurrappadi@nvidia.com> Cc: vincent.guittot@linaro.org <vincent.guittot@linaro.org> Cc: yuyang.du@intel.com <yuyang.du@intel.com> Link: http://lkml.kernel.org/r/55EDAF43.30500@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/fair: Name utilization related data and functions consistentlyDietmar Eggemann1-18/+19
Use the advent of the per-entity load tracking rewrite to streamline the naming of utilization related data and functions by using {prefix_}util{_suffix} consistently. Moreover call both signals ({se,cfs}.avg.util_avg) utilization. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Dietmar Eggemann <Dietmar.Eggemann@arm.com> Cc: Juri Lelli <Juri.Lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: daniel.lezcano@linaro.org Cc: mturquette@baylibre.com Cc: pang.xunlei@zte.com.cn Cc: rjw@rjwysocki.net Cc: sgurrappadi@nvidia.com Cc: vincent.guittot@linaro.org Cc: yuyang.du@intel.com Link: http://lkml.kernel.org/r/1439569394-11974-5-git-send-email-morten.rasmussen@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/fair: Make utilization tracking CPU scale-invariantDietmar Eggemann3-5/+6
Besides the existing frequency scale-invariance correction factor, apply CPU scale-invariance correction factor to utilization tracking to compensate for any differences in compute capacity. This could be due to micro-architectural differences (i.e. instructions per seconds) between cpus in HMP systems (e.g. big.LITTLE), and/or differences in the current maximum frequency supported by individual cpus in SMP systems. In the existing implementation utilization isn't comparable between cpus as it is relative to the capacity of each individual CPU. Each segment of the sched_avg.util_sum geometric series is now scaled by the CPU performance factor too so the sched_avg.util_avg of each sched entity will be invariant from the particular CPU of the HMP/SMP system on which the sched entity is scheduled. With this patch, the utilization of a CPU stays relative to the max CPU performance of the fastest CPU in the system. In contrast to utilization (sched_avg.util_sum), load (sched_avg.load_sum) should not be scaled by compute capacity. The utilization metric is based on running time which only makes sense when cpus are _not_ fully utilized (utilization cannot go beyond 100% even if more tasks are added), where load is runnable time which isn't limited by the capacity of the CPU and therefore is a better metric for overloaded scenarios. If we run two nice-0 busy loops on two cpus with different compute capacity their load should be similar since their compute demands are the same. We have to assume that the compute demand of any task running on a fully utilized CPU (no spare cycles = 100% utilization) is high and the same no matter of the compute capacity of its current CPU, hence we shouldn't scale load by CPU capacity. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/55CE7409.1000700@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/fair: Convert arch_scale_cpu_capacity() from weak function to #defineMorten Rasmussen3-26/+12
Bring arch_scale_cpu_capacity() in line with the recent change of its arch_scale_freq_capacity() sibling in commit dfbca41f3479 ("sched: Optimize freq invariant accounting") from weak function to #define to allow inlining of the function. While at it, remove the ARCH_CAPACITY sched_feature as well. With the change to #define there isn't a straightforward way to allow runtime switch between an arch implementation and the default implementation of arch_scale_cpu_capacity() using sched_feature. The default was to use the arch-specific implementation, but only the arm architecture provides one and that is essentially equivalent to the default implementation. Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Dietmar Eggemann <Dietmar.Eggemann@arm.com> Cc: Juri Lelli <Juri.Lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: daniel.lezcano@linaro.org Cc: mturquette@baylibre.com Cc: pang.xunlei@zte.com.cn Cc: rjw@rjwysocki.net Cc: sgurrappadi@nvidia.com Cc: vincent.guittot@linaro.org Cc: yuyang.du@intel.com Link: http://lkml.kernel.org/r/1439569394-11974-3-git-send-email-morten.rasmussen@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/fair: Make load tracking frequency scale-invariantDietmar Eggemann2-13/+20
Apply frequency scaling correction factor to per-entity load tracking to make it frequency invariant. Currently, load appears bigger when the CPU is running slower which affects load-balancing decisions. Each segment of the sched_avg.load_sum geometric series is now scaled by the current frequency so that the sched_avg.load_avg of each sched entity will be invariant from frequency scaling. Moreover, cfs_rq.runnable_load_sum is scaled by the current frequency as well. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Vincent Guittot <vincent.guittot@linaro.org> Cc: Dietmar Eggemann <Dietmar.Eggemann@arm.com> Cc: Juri Lelli <Juri.Lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: daniel.lezcano@linaro.org Cc: mturquette@baylibre.com Cc: pang.xunlei@zte.com.cn Cc: rjw@rjwysocki.net Cc: sgurrappadi@nvidia.com Cc: yuyang.du@intel.com Link: http://lkml.kernel.org/r/1439569394-11974-2-git-send-email-morten.rasmussen@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/numa: Convert sched_numa_balancing to a static_branchSrikar Dronamraju3-11/+11
Variable sched_numa_balancing toggles numa_balancing feature. Hence moving from a simple read mostly variable to a more apt static_branch. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Mike Galbraith <efault@gmx.de> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1439310261-16124-1-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/numa: Remove the NUMA sched_featureSrikar Dronamraju2-22/+0
Variable sched_numa_balancing is available for both CONFIG_SCHED_DEBUG and !CONFIG_SCHED_DEBUG. All code paths now check for sched_numa_balancing. Hence remove sched_feat(NUMA). Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1439290813-6683-4-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/numa: Disable sched_numa_balancing on UMA systemsSrikar Dronamraju3-17/+7
Commit 2a1ed24 ("sched/numa: Prefer NUMA hotness over cache hotness") sets sched feature NUMA to true. However this can enable NUMA hinting faults on a UMA system. This commit ensures that NUMA hinting faults occur only on a NUMA system by setting/resetting sched_numa_balancing. This commit: - Makes sched_numa_balancing common to CONFIG_SCHED_DEBUG and !CONFIG_SCHED_DEBUG. Earlier it was only in !CONFIG_SCHED_DEBUG. - Checks for sched_numa_balancing instead of sched_feat(NUMA). Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1439290813-6683-3-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/numa: Rename numabalancing_enabled to sched_numa_balancingSrikar Dronamraju3-8/+8
Simple rename of the 'numabalancing_enabled' variable to 'sched_numa_balancing'. No functional changes. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1439290813-6683-2-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/fair: Fix nohz.next_balance updateVincent Guittot1-4/+30
Since commit: d4573c3e1c99 ("sched: Improve load balancing in the presence of idle CPUs") the ILB CPU starts with the idle load balancing of other idle CPUs and finishes with itself in order to speed up the spread of tasks in all idle CPUs. The this_rq->next_balance is still used in nohz_idle_balance() as an intermediate step to gather the shortest next balance before updating nohz.next_balance. But the former has not been updated yet and is likely to be set with the current jiffies. As a result, the nohz.next_balance will be set with current jiffies instead of the real next balance date. This generates spurious kicks of nohz ilde balance. nohz_idle_balance() must set the nohz.next_balance without taking into account this_rq->next_balance which is not updated yet. Then, this_rq will update nohz.next_update with its next_balance once updated and if necessary. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Jason Low <jason.low2@hp.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: preeti@linux.vnet.ibm.com Link: http://lkml.kernel.org/r/1438595750-20455-1-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/core: Delete PF_EXITING checks from cpu_cgroup_exit() callbackKirill Tkhai1-8/+0
cgroup_exit() is not called from copy_process() after commit: e8604cb43690 ("cgroup: fix spurious lockdep warning in cgroup_exit()") from do_exit(). So this check is useless and the comment is obsolete. Signed-off-by: Kirill Tkhai <ktkhai@odin.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/55E444C8.3020402@odin.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/core: Remove unused argument from sched_class::task_move_groupPeter Zijlstra3-3/+3
The previous patches made the second argument go unused, remove it. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Byungchul Park <byungchul.park@lge.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/fair: Unify switched_{from,to}_fair() and task_move_group_fair()Byungchul Park1-77/+52
By observing that switched_from_fair() detaches from a runqueue, and switched_to_fair() attaches to a runqueue, we can see that task_move_group_fair() is one followed by the other with flipping the runqueue in between. Therefore extract all the common bits and implement all three functions in terms of them. This should fix a few corner cases wrt. vruntime normalization; where, when we take a task off of a runqueue we convert to an approximation of lag by subtracting min_vruntime, and when placing a task on the a runqueue to the reverse. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Byungchul Park <byungchul.park@lge.com> [peterz: Changelog] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: yuyang.du@intel.com Link: http://lkml.kernel.org/r/1440069720-27038-6-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/fair: Make the entity load aging on attaching tunablePeter Zijlstra2-0/+6
In case there are problems with the aging on attach, provide a debug knob to turn it off. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Byungchul Park <byungchul.park@lge.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Cc: yuyang.du@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/fair: Fix switched_to_fair()'s per entity load trackingByungchul Park1-0/+23
Where switched_from_fair() will remove the entity's load from the runqueue, switched_to_fair() does not currently add it back. This means that when a task leaves the fair class for a short duration; say because of PI; we loose its load contribution. This can ripple forward and disturb the load tracking because other operations (enqueue, dequeue) assume its factored in. Only once the runqueue empties will the load tracking recover. When we add it back in, age the per entity average to match up with the runqueue age. This has the obvious problem that if the task leaves the fair class for a significant time, the load will age to 0. Employ the normal migration rule for inter-runqueue moves in task_move_group_fair(). Again, there is the obvious problem of the task migrating while not in the fair class. The alternative solution would be to to omit the chunk in attach_entity_load_avg(), which would effectively reset the timestamp and use whatever avg there was. Signed-off-by: Byungchul Park <byungchul.park@lge.com> [ Rewrote the changelog and comments. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: yuyang.du@intel.com Link: http://lkml.kernel.org/r/1440069720-27038-5-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/fair: Have task_move_group_fair() also detach entity load from the old runqueueByungchul Park1-1/+5
Since we attach the entity load to the new runqueue, we should also detatch the entity load from the old runqueue, otherwise load can accumulate. Signed-off-by: Byungchul Park <byungchul.park@lge.com> [ Rewrote the changelog. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: yuyang.du@intel.com Link: http://lkml.kernel.org/r/1440069720-27038-4-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/fair: Have task_move_group_fair() unconditionally add the entity load to the runqueueByungchul Park1-5/+4
Currently we conditionally add the entity load to the rq when moving the task between cgroups. This doesn't make sense as we always 'migrate' the task between cgroups, so we should always migrate the load too. [ The history here is that we used to only migrate the blocked load which was only meaningfull when !queued. ] Signed-off-by: Byungchul Park <byungchul.park@lge.com> [ Rewrote the changelog. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: yuyang.du@intel.com Link: http://lkml.kernel.org/r/1440069720-27038-3-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/fair: Factor out the {at,de}taching of the per entity load {to,from} the runqueueByungchul Park1-39/+38
Currently we open-code the addition/subtraction of the per entity load to/from the runqueue, factor this out into helper functions. Signed-off-by: Byungchul Park <byungchul.park@lge.com> [ Rewrote the changelog. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: yuyang.du@intel.com Link: http://lkml.kernel.org/r/1440069720-27038-2-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-12Linux 4.3-rc1Linus Torvalds1-2/+2
2015-09-12blk: rq_data_dir() should not return a booleanLinus Torvalds1-1/+1
rq_data_dir() returns either READ or WRITE (0 == READ, 1 == WRITE), not a boolean value. Now, admittedly the "!= 0" doesn't really change the value (0 stays as zero, 1 stays as one), but it's not only redundant, it confuses gcc, and causes gcc to warn about the construct switch (rq_data_dir(req)) { case READ: ... case WRITE: ... that we have in a few drivers. Now, the gcc warning is silly and stupid (it seems to warn not about the switch value having a different type from the case statements, but about _any_ boolean switch value), but in this case the code itself is silly and stupid too, so let's just change it, and get rid of warnings like this: drivers/block/hd.c: In function ‘hd_request’: drivers/block/hd.c:630:11: warning: switch condition has boolean value [-Wswitch-bool] switch (rq_data_dir(req)) { The odd '!= 0' came in when "cmd_flags" got turned into a "u64" in commit 5953316dbf90 ("block: make rq->cmd_flags be 64-bit") and is presumably because the old code (that just did a logical 'and' with 1) would then end up making the type of rq_data_dir() be u64 too. But if we want to retain the old regular integer type, let's just cast the result to 'int' rather than use that rather odd '!= 0'. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-12writeback: plug writeback in wb_writeback() and writeback_inodes_wb()Linus Torvalds1-0/+6
We had to revert the pluggin in writeback_sb_inodes() because the wb->list_lock is held, but we could easily plug at a higher level before taking that lock, and unplug after releasing it. This does that. Chris will run performance numbers, just to verify that this approach is comparable to the alternative (we could just drop and re-take the lock around the blk_finish_plug() rather than these two commits. I'd have preferred waiting for actual performance numbers before picking one approach over the other, but I don't want to release rc1 with the known "sleeping function called from invalid context" issue, so I'll pick this cleanup version for now. But if the numbers show that we really want to plug just at the writeback_sb_inodes() level, and we should just play ugly games with the spinlock, we'll switch to that. Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Neil Brown <neilb@suse.de> Cc: Jan Kara <jack@suse.cz> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-12cpu/hotplug: Read_lock(tasklist_lock) doesn't need to disable irqsOleg Nesterov1-4/+4
check_for_tasks() doesn't need to disable irqs, recursive read_lock() from interrupt is fine. While at it, s/do_each_thread/for_each_process_thread/. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Kirill Tkhai <ktkhai@odin.com> Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Kirill Tkhai <ktkhai@parallels.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150910130750.GA20055@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-11thermal: fix intel PCH thermal driver mismergeLinus Torvalds1-7/+4
I didn't notice this when merging the thermal code from Zhang, but his merge (commit 5a924a07f882: "Merge branches 'thermal-core' and 'thermal-intel' of .git into next") of the thermal-core and thermal-intel branches was wrong. In thermal-core, commit 17e8351a7739 ("thermal: consistently use int for temperatures") converted the thermal layer to use "int" for temperatures. But in parallel, in the thermal-intel branch commit d0a12625d2ff ("thermal: Add Intel PCH thermal driver") added support for the intel PCH thermal sensor using the old interfaces that used "unsigned long" pointers. This resulted in warnings like this: drivers/thermal/intel_pch_thermal.c:184:14: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types] .get_temp = pch_thermal_get_temp, ^ drivers/thermal/intel_pch_thermal.c:184:14: note: (near initialization for ‘tzd_ops.get_temp’) drivers/thermal/intel_pch_thermal.c:186:19: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types] .get_trip_temp = pch_get_trip_temp, ^ drivers/thermal/intel_pch_thermal.c:186:19: note: (near initialization for ‘tzd_ops.get_trip_temp’) This fixes it. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11ARCv2: [axs103_smp] Reduce clk for SMP FPGA configsVineet Gupta1-0/+2
Newer bitfiles needs the reduced clk even for SMP builds Cc: <stable@vger.kernel.org> #4.2 Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11revert "ocfs2/dlm: use list_for_each_entry instead of list_for_each"Andrew Morton1-2/+4
Revert commit f83c7b5e9fd6 ("ocfs2/dlm: use list_for_each_entry instead of list_for_each"). list_for_each_entry() will dereference its `pos' argument, which can be NULL in dlm_process_recovery_data(). Reported-by: Julia Lawall <julia.lawall@lip6.fr> Reported-by: Fengguang Wu <fengguang.wu@gmail.com> Cc: Joseph Qi <joseph.qi@huawei.com> Cc: Mark Fasheh <mfasheh@suse.de> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11mm/early_ioremap: add explicit #include of asm/early_ioremap.hArd Biesheuvel1-0/+1
Commit 6b0f68e32ea8 ("mm: add utility for early copy from unmapped ram") introduces a function copy_from_early_mem() into mm/early_ioremap.c which itself calls early_memremap()/early_memunmap(). However, since early_memunmap() has not been declared yet at this point in the .c file, nor by any explicitly included header files, we are depending on a transitive include of asm/early_ioremap.h to declare it, which is fragile. So instead, include this header explicitly. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Mark Salter <msalter@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11fs/seq_file: convert int seq_vprint/seq_printf/etc... returns to voidJoe Perches4-50/+45
The seq_<foo> function return values were frequently misused. See: commit 1f33c41c03da ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") All uses of these return values have been removed, so convert the return types to void. Miscellanea: o Move seq_put_decimal_<type> and seq_escape prototypes closer the other seq_vprintf prototypes o Reorder seq_putc and seq_puts to return early on overflow o Add argument names to seq_vprintf and seq_printf o Update the seq_escape kernel-doc o Convert a couple of leading spaces to tabs in seq_escape Signed-off-by: Joe Perches <joe@perches.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mark Brown <broonie@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Joerg Roedel <jroedel@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11selftests: enhance membarrier syscall testMathieu Desnoyers1-25/+75
Update the membarrier syscall self-test to match the membarrier interface. Extend coverage of the interface. Consider ENOSYS as a "SKIP" test, since it is a valid configuration, but does not allow testing the system call. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Pranith Kumar <bobby.prani@gmail.com> Cc: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11selftests: add membarrier syscall testPranith Kumar4-0/+84
Add a self test for the membarrier system call. Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11sys_membarrier(): system-wide memory barrier (generic, x86)Mathieu Desnoyers11-1/+151
Here is an implementation of a new system call, sys_membarrier(), which executes a memory barrier on all threads running on the system. It is implemented by calling synchronize_sched(). It can be used to distribute the cost of user-space memory barriers asymmetrically by transforming pairs of memory barriers into pairs consisting of sys_membarrier() and a compiler barrier. For synchronization primitives that distinguish between read-side and write-side (e.g. userspace RCU [1], rwlocks), the read-side can be accelerated significantly by moving the bulk of the memory barrier overhead to the write-side. The existing applications of which I am aware that would be improved by this system call are as follows: * Through Userspace RCU library (http://urcu.so) - DNS server (Knot DNS) https://www.knot-dns.cz/ - Network sniffer (http://netsniff-ng.org/) - Distributed object storage (https://sheepdog.github.io/sheepdog/) - User-space tracing (http://lttng.org) - Network storage system (https://www.gluster.org/) - Virtual routers (https://events.linuxfoundation.org/sites/events/files/slides/DPDK_RCU_0MQ.pdf) - Financial software (https://lkml.org/lkml/2015/3/23/189) Those projects use RCU in userspace to increase read-side speed and scalability compared to locking. Especially in the case of RCU used by libraries, sys_membarrier can speed up the read-side by moving the bulk of the memory barrier cost to synchronize_rcu(). * Direct users of sys_membarrier - core dotnet garbage collector (https://github.com/dotnet/coreclr/issues/198) Microsoft core dotnet GC developers are planning to use the mprotect() side-effect of issuing memory barriers through IPIs as a way to implement Windows FlushProcessWriteBuffers() on Linux. They are referring to sys_membarrier in their github thread, specifically stating that sys_membarrier() is what they are looking for. To explain the benefit of this scheme, let's introduce two example threads: Thread A (non-frequent, e.g. executing liburcu synchronize_rcu()) Thread B (frequent, e.g. executing liburcu rcu_read_lock()/rcu_read_unlock()) In a scheme where all smp_mb() in thread A are ordering memory accesses with respect to smp_mb() present in Thread B, we can change each smp_mb() within Thread A into calls to sys_membarrier() and each smp_mb() within Thread B into compiler barriers "barrier()". Before the change, we had, for each smp_mb() pairs: Thread A Thread B previous mem accesses previous mem accesses smp_mb() smp_mb() following mem accesses following mem accesses After the change, these pairs become: Thread A Thread B prev mem accesses prev mem accesses sys_membarrier() barrier() follow mem accesses follow mem accesses As we can see, there are two possible scenarios: either Thread B memory accesses do not happen concurrently with Thread A accesses (1), or they do (2). 1) Non-concurrent Thread A vs Thread B accesses: Thread A Thread B prev mem accesses sys_membarrier() follow mem accesses prev mem accesses barrier() follow mem accesses In this case, thread B accesses will be weakly ordered. This is OK, because at that point, thread A is not particularly interested in ordering them with respect to its own accesses. 2) Concurrent Thread A vs Thread B accesses Thread A Thread B prev mem accesses prev mem accesses sys_membarrier() barrier() follow mem accesses follow mem accesses In this case, thread B accesses, which are ensured to be in program order thanks to the compiler barrier, will be "upgraded" to full smp_mb() by synchronize_sched(). * Benchmarks On Intel Xeon E5405 (8 cores) (one thread is calling sys_membarrier, the other 7 threads are busy looping) 1000 non-expedited sys_membarrier calls in 33s =3D 33 milliseconds/call. * User-space user of this system call: Userspace RCU library Both the signal-based and the sys_membarrier userspace RCU schemes permit us to remove the memory barrier from the userspace RCU rcu_read_lock() and rcu_read_unlock() primitives, thus significantly accelerating them. These memory barriers are replaced by compiler barriers on the read-side, and all matching memory barriers on the write-side are turned into an invocation of a memory barrier on all active threads in the process. By letting the kernel perform this synchronization rather than dumbly sending a signal to every process threads (as we currently do), we diminish the number of unnecessary wake ups and only issue the memory barriers on active threads. Non-running threads do not need to execute such barrier anyway, because these are implied by the scheduler context switches. Results in liburcu: Operations in 10s, 6 readers, 2 writers: memory barriers in reader: 1701557485 reads, 2202847 writes signal-based scheme: 9830061167 reads, 6700 writes sys_membarrier: 9952759104 reads, 425 writes sys_membarrier (dyn. check): 7970328887 reads, 425 writes The dynamic sys_membarrier availability check adds some overhead to the read-side compared to the signal-based scheme, but besides that, sys_membarrier slightly outperforms the signal-based scheme. However, this non-expedited sys_membarrier implementation has a much slower grace period than signal and memory barrier schemes. Besides diminishing the number of wake-ups, one major advantage of the membarrier system call over the signal-based scheme is that it does not need to reserve a signal. This plays much more nicely with libraries, and with processes injected into for tracing purposes, for which we cannot expect that signals will be unused by the application. An expedited version of this system call can be added later on to speed up the grace period. Its implementation will likely depend on reading the cpu_curr()->mm without holding each CPU's rq lock. This patch adds the system call to x86 and to asm-generic. [1] http://urcu.so membarrier(2) man page: MEMBARRIER(2) Linux Programmer's Manual MEMBARRIER(2) NAME membarrier - issue memory barriers on a set of threads SYNOPSIS #include <linux/membarrier.h> int membarrier(int cmd, int flags); DESCRIPTION The cmd argument is one of the following: MEMBARRIER_CMD_QUERY Query the set of supported commands. It returns a bitmask of supported commands. MEMBARRIER_CMD_SHARED Execute a memory barrier on all threads running on the system. Upon return from system call, the caller thread is ensured that all running threads have passed through a state where all memory accesses to user-space addresses match program order between entry to and return from the system call (non-running threads are de facto in such a state). This covers threads from all pro=E2=80=90 cesses running on the system. This command returns 0. The flags argument needs to be 0. For future extensions. All memory accesses performed in program order from each targeted thread is guaranteed to be ordered with respect to sys_membarrier(). If we use the semantic "barrier()" to represent a compiler barrier forcing memory accesses to be performed in program order across the barrier, and smp_mb() to represent explicit memory barriers forcing full memory ordering across the barrier, we have the following ordering table for each pair of barrier(), sys_membarrier() and smp_mb(): The pair ordering is detailed as (O: ordered, X: not ordered): barrier() smp_mb() sys_membarrier() barrier() X X O smp_mb() X O O sys_membarrier() O O O RETURN VALUE On success, these system calls return zero. On error, -1 is returned, and errno is set appropriately. For a given command, with flags argument set to 0, this system call is guaranteed to always return the same value until reboot. ERRORS ENOSYS System call is not implemented. EINVAL Invalid arguments. Linux 2015-04-15 MEMBARRIER(2) Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Nicholas Miell <nmiell@comcast.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Pranith Kumar <bobby.prani@gmail.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11MODSIGN: fix a compilation warning in extract-certDavid Howells1-1/+1
Fix the following warning when compiling extract-cert: scripts/extract-cert.c: In function `write_cert': scripts/extract-cert.c:89:2: warning: format not a string literal and no format arguments [-Wformat-security] ERR(!i2d_X509_bio(wb, x509), cert_dst); ^ whereby the ERR() macro is taking cert_dst as the format string. "%s" should be used as the format string as the path could contain special characters. Signed-off-by: David Howells <dhowells@redhat.com> Reported-by: Jim Davis <jim.epost@gmail.com> Acked-by : David Woodhouse <david.woodhouse@intel.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11Revert "writeback: plug writeback at a high level"Linus Torvalds1-3/+4
This reverts commit d353d7587d02116b9732d5c06615aed75a4d3a47. Doing the block layer plug/unplug inside writeback_sb_inodes() is broken, because that function is actually called with a spinlock held: wb->list_lock, as pointed out by Chris Mason. Chris suggested just dropping and re-taking the spinlock around the blk_finish_plug() call (the plgging itself can happen under the spinlock), and that would technically work, but is just disgusting. We do something fairly similar - but not quite as disgusting because we at least have a better reason for it - in writeback_single_inode(), so it's not like the caller can depend on the lock being held over the call, but in this case there just isn't any good reason for that "release and re-take the lock" pattern. [ In general, we should really strive to avoid the "release and retake" pattern for locks, because in the general case it can easily cause subtle bugs when the caller caches any state around the call that might be invalidated by dropping the lock even just temporarily. ] But in this case, the plugging should be easy to just move up to the callers before the spinlock is taken, which should even improve the effectiveness of the plug. So there is really no good reason to play games with locking here. I'll send off a test-patch so that Dave Chinner can verify that that plug movement works. In the meantime this just reverts the problematic commit and adds a comment to the function so that we hopefully don't make this mistake again. Reported-by: Chris Mason <clm@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Neil Brown <neilb@suse.de> Cc: Jan Kara <jack@suse.cz> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11scsi_dh: fix randconfig build errorChristoph Hellwig1-1/+1
It looks like the Kconfig check that was meant to fix this (commit fe9233fb6914a0eb20166c967e3020f7f0fba2c9 [SCSI] scsi_dh: fix kconfig related build errors) was actually reversed, but no-one noticed until the new set of patches which separated DM and SCSI_DH). Fixes: fe9233fb6914a0eb20166c967e3020f7f0fba2c9 Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-09-11target: use stringify.h instead of own definitionDavid Disseldorp2-5/+2
Signed-off-by: David Disseldorp <ddiss@suse.de> Acked-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-09-11target/user: Fix UFLAG_UNKNOWN_OP handlingAndy Grover1-8/+2
Calling transport_generic_request_failure() from here causes list corruption. We should be using target_complete_cmd() instead. Which we do in all other cases, so the UNKNOWN_OP case can become just another member of the big else/if chain in tcmu_handle_completion(). Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-09-11target: Remove no-op conditionalAndy Grover1-2/+1
This does nothing, and there are many other places where transport_cmd_check_stop_to_fabric()'s retval is not checked>, If we wanted to check it here, we should probably do it those other places too. Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-09-11target/user: Remove unused variableAndy Grover1-1/+0
We don't use it any more. Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-09-11target: Fix max_cmd_sn increment w/o cmdsn mutex regressionsRoland Dreier2-4/+5
Current for-next iscsi target is broken: commit 109e2381749c1cfd94a0d22b2b54142539024973 Author: Roland Dreier <roland@purestorage.com> Date: Thu Jul 23 14:53:32 2015 -0700 target: Drop iSCSI use of mutex around max_cmd_sn increment This patch fixes incorrect pr_debug() + atomic_inc_return() usage within iscsit_increment_maxcmdsn() code. Also fix funny iscsit_determine_maxcmdsn() usage and update iscsi_target_do_tx_login_io() code. Reported-by: Sagi Grimberg <sagig@mellanox.com> Cc: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Roland Dreier <roland@purestorage.com> Cc: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-09-11target: Attach EXTENDED_COPY local I/O descriptors to xcopy_pt_sessNicholas Bellinger1-2/+4
This patch is a >= v4.1 regression bug-fix where control CDB emulation logic in commit 38b57f82 now expects a se_cmd->se_sess pointer to exist when determining T10-PI support is to be exposed for initiator host ports. To address this bug, go ahead and add locally generated se_cmd descriptors for copy-offload block-copy to it's own stand-alone se_session nexus, while the parent EXTENDED_COPY se_cmd descriptor remains associated with it's originating se_cmd->se_sess nexus. Note a valid se_cmd->se_sess is also required for future support of WRITE_INSERT and READ_STRIP software emulation when submitting backend I/O to se_device that exposes T10-PI suport. Reported-by: Alex Gorbachev <ag@iss-integration.com> Tested-by: Alex Gorbachev <ag@iss-integration.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Doug Gilbert <dgilbert@interlog.com> Cc: <stable@vger.kernel.org> # v4.1+ Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-09-11target/qla2xxx: Honor max_data_sg_nents I/O transfer limitNicholas Bellinger4-4/+78
This patch adds an optional fabric driver provided SGL limit that target-core will honor as it's own internal I/O maximum transfer length limit, as exposed by EVPD=0xb0 block limits parameters. This is required for handling cases when host I/O transfer length exceeds the requested EVPD block limits maximum transfer length. The initial user of this logic is qla2xxx, so that we can avoid having to reject I/Os from some legacy FC hosts where EVPD=0xb0 parameters are not honored. When se_cmd payload length exceeds the provided limit in target_check_max_data_sg_nents() code, se_cmd->data_length + se_cmd->prot_length are reset with se_cmd->residual_count plus underflow bit for outgoing TFO response callbacks. It also checks for existing CDB level underflow + overflow and recalculates final residual_count as necessary. Note this patch currently assumes 1:1 mapping of PAGE_SIZE per struct scatterlist entry. Reported-by: Craig Watson <craig.watson@vanguard-rugged.com> Cc: Craig Watson <craig.watson@vanguard-rugged.com> Tested-by: Himanshu Madhani <himanshu.madhani@qlogic.com> Cc: Roland Dreier <roland@purestorage.com> Cc: Arun Easi <arun.easi@qlogic.com> Cc: Giridhar Malavali <giridhar.malavali@qlogic.com> Cc: Andrew Vasquez <andrew.vasquez@qlogic.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-09-11sched: 'Annotate' migrate_tasks()Wanpeng Li1-3/+26
Kernel testing triggered this warning: | WARNING: CPU: 0 PID: 13 at kernel/sched/core.c:1156 do_set_cpus_allowed+0x7e/0x80() | Modules linked in: | CPU: 0 PID: 13 Comm: migration/0 Not tainted 4.2.0-rc1-00049-g25834c7 #2 | Call Trace: | dump_stack+0x4b/0x75 | warn_slowpath_common+0x8b/0xc0 | warn_slowpath_null+0x22/0x30 | do_set_cpus_allowed+0x7e/0x80 | cpuset_cpus_allowed_fallback+0x7c/0x170 | select_fallback_rq+0x221/0x280 | migration_call+0xe3/0x250 | notifier_call_chain+0x53/0x70 | __raw_notifier_call_chain+0x1e/0x30 | cpu_notify+0x28/0x50 | take_cpu_down+0x22/0x40 | multi_cpu_stop+0xd5/0x140 | cpu_stopper_thread+0xbc/0x170 | smpboot_thread_fn+0x174/0x2f0 | kthread+0xc4/0xe0 | ret_from_kernel_thread+0x21/0x30 As Peterz pointed out: | So the normal rules for changing task_struct::cpus_allowed are holding | both pi_lock and rq->lock, such that holding either stabilizes the mask. | | This is so that wakeup can happen without rq->lock and load-balance | without pi_lock. | | From this we already get the relaxation that we can omit acquiring | rq->lock if the task is not on the rq, because in that case | load-balancing will not apply to it. | | ** these are the rules currently tested in do_set_cpus_allowed() ** | | Now, since __set_cpus_allowed_ptr() uses task_rq_lock() which | unconditionally acquires both locks, we could get away with holding just | rq->lock when on_rq for modification because that'd still exclude | __set_cpus_allowed_ptr(), it would also work against | __kthread_bind_mask() because that assumes !on_rq. | | That said, this is all somewhat fragile. | | Now, I don't think dropping rq->lock is quite as disastrous as it | usually is because !cpu_active at this point, which means load-balance | will not interfere, but that too is somewhat fragile. | | So we end up with a choice of two fragile.. This patch fixes it by following the rules for changing task_struct::cpus_allowed with both pi_lock and rq->lock held. Reported-by: kernel test robot <ying.huang@intel.com> Reported-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> [ Modified changelog and patch. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/BLU436-SMTP1660820490DE202E3934ED3806E0@phx.gbl Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-11drm/nouveau/device: enable c800 quirk for tecra w50Ben Skeggs1-0/+1
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2015-09-11drm/nouveau/clk/gt215: Unbreak engine pausing for GT21x/MCP7xRoy Spliet1-1/+1
Typo that snuck in with commit 6979c6303a4abf263753cd9d577d79f05c6e8c47 Signed-off-by: Roy Spliet <rspliet@eclipso.eu> Reported-by: Pierre Moreau <pierre.morrow@free.fr> Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2015-09-11drm/nouveau/gr/nv04: fix big endian setting on gr contextIlia Mirkin1-3/+3
Broken since "gr: convert user classes to new-style nvkm_object" Tested on a PPC64 G5 + NV34 Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu> Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2015-09-11drm/qxl: validate monitors config modesJonathon Jongsma2-26/+42
Due to some recent changes in drm_helper_probe_single_connector_modes_merge_bits(), old custom modes were not being pruned properly. In current kernels, drm_mode_validate_basic() is called to sanity-check each mode in the list. If the sanity-check passes, the mode's status gets set to to MODE_OK. In older kernels this check was not done, so old custom modes would still have a status of MODE_UNVERIFIED at this point, and would therefore be pruned later in the function. As a result of this new behavior, the list of modes for a device always includes every custom mode ever configured for the device, with the largest one listed first. Since desktop environments usually choose the first preferred mode when a hotplug event is emitted, this had the result of making it very difficult for the user to reduce the size of the display. The qxl driver did implement the mode_valid connector function, but it was empty. In order to restore the old behavior where old custom modes are pruned, we implement a proper mode_valid function for the qxl driver. This function now checks each mode against the last configured custom mode and the list of standard modes. If the mode doesn't match any of these, its status is set to MODE_BAD so that it will be pruned as expected. Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Dave Airlie <airlied@redhat.com>
2015-09-10dma-mapping: consolidate dma_set_maskChristoph Hellwig24-169/+28
Almost everyone implements dma_set_mask the same way, although some time that's hidden in ->set_dma_mask methods. This patch consolidates those into a common implementation that either calls ->set_dma_mask if present or otherwise uses the default implementation. Some architectures used to only call ->set_dma_mask after the initial checks, and those instance have been fixed to do the full work. h8300 implemented dma_set_mask bogusly as a no-ops and has been fixed. Unfortunately some architectures overload unrelated semantics like changing the dma_ops into it so we still need to allow for an architecture override for now. [jcmvbkbc@gmail.com: fix xtensa] Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Russell King <linux@arm.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Michal Simek <monstr@monstr.eu> Cc: Jonas Bonn <jonas@southpole.se> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10dma-mapping: consolidate dma_supportedChristoph Hellwig18-98/+25
Most architectures just call into ->dma_supported, but some also return 1 if the method is not present, or 0 if no dma ops are present (although that should never happeb). Consolidate this more broad version into common code. Also fix h8300 which inorrectly always returned 0, which would have been a problem if it's dma_set_mask implementation wasn't a similarly buggy noop. As a few architectures have much more elaborate implementations, we still allow for arch overrides. [jcmvbkbc@gmail.com: fix xtensa] Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Russell King <linux@arm.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Michal Simek <monstr@monstr.eu> Cc: Jonas Bonn <jonas@southpole.se> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10dma-mapping: cosolidate dma_mapping_errorChristoph Hellwig18-146/+19
Currently there are three valid implementations of dma_mapping_error: (1) call ->mapping_error (2) check for a hardcoded error code (3) always return 0 This patch provides a common implementation that calls ->mapping_error if present, then checks for DMA_ERROR_CODE if defined or otherwise returns 0. [jcmvbkbc@gmail.com: fix xtensa] Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Russell King <linux@arm.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Michal Simek <monstr@monstr.eu> Cc: Jonas Bonn <jonas@southpole.se> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10dma-mapping: consolidate dma_{alloc,free}_noncoherentChristoph Hellwig19-99/+39
Most architectures do not support non-coherent allocations and either define dma_{alloc,free}_noncoherent to their coherent versions or stub them out. Openrisc uses dma_{alloc,free}_attrs to implement them, and only Mips implements them directly. This patch moves the Openrisc version to common code, and handles the DMA_ATTR_NON_CONSISTENT case in the mips dma_map_ops instance. Note that actual non-coherent allocations require a dma_cache_sync implementation, so if non-coherent allocations didn't work on an architecture before this patch they still won't work after it. [jcmvbkbc@gmail.com: fix xtensa] Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Russell King <linux@arm.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Michal Simek <monstr@monstr.eu> Cc: Jonas Bonn <jonas@southpole.se> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>