linux/include
Paul E. McKenney ac1bea8578 sched,rcu: Make cond_resched() report RCU quiescent states
Given a CPU running a loop containing cond_resched(), with no
other tasks runnable on that CPU, RCU will eventually report RCU
CPU stall warnings due to lack of quiescent states.  Fortunately,
every call to cond_resched() is a perfectly good quiescent state.
Unfortunately, invoking rcu_note_context_switch() is a bit heavyweight
for cond_resched(), especially given the need to disable preemption,
and, for RCU-preempt, interrupts as well.

This commit therefore maintains a per-CPU counter that causes
cond_resched(), cond_resched_lock(), and cond_resched_softirq() to call
rcu_note_context_switch(), but only about once per 256 invocations.
This ratio was chosen in keeping with the relative time constants of
RCU grace periods.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:11 -07:00
..
acpi IOMMU Upates for Linux v3.15 2014-04-05 18:46:26 -07:00
asm-generic LLVMLinux Patches for v3.15 2014-04-12 17:00:40 -07:00
clocksource
crypto
drm Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-04-11 12:04:15 -07:00
dt-bindings The clock framework changes for 3.15 look similar to past pull requests. 2014-04-05 18:39:18 -07:00
keys
kvm
linux sched,rcu: Make cond_resched() report RCU quiescent states 2014-05-14 09:46:11 -07:00
math-emu
media [media] rc-core: remove generic scancode filter 2014-04-06 11:30:29 -03:00
memory
misc
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2014-04-12 17:31:22 -07:00
pcmcia
ras
rdma Merge branches 'core', 'cxgb4', 'ip-roce', 'iser', 'misc', 'mlx4', 'nes', 'ocrdma', 'qib', 'sgwrapper', 'srp' and 'usnic' into for-next 2014-04-03 08:30:17 -07:00
rxrpc
scsi scsi: Make sure cmd_flags are 64-bit 2014-04-09 20:26:20 -06:00
sound ALSA: cs8427: separate HW initialization 2014-04-03 14:59:48 +02:00
target target/sbc: Add sbc_dif_read_strip software emulation 2014-04-07 01:48:57 -07:00
trace This includes the final patch to clean up and fix the issue with the 2014-04-12 13:06:10 -07:00
uapi Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media 2014-04-12 16:18:17 -07:00
video fbdev changes for 3.15 (OMAP) 2014-04-07 10:47:51 -07:00
xen
Kbuild