[GIT PULL] CSD-lock changes for v6.13

From: Paul E. McKenney
Date: Sun Nov 17 2024 - 13:37:42 EST


Hello, Linus,

When the v6.13 merge window opens, please pull this CSD-lock update from:

git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git tags/csd-lock.2024.11.16a
# HEAD: 9861f7f66f98a6358c944c17a5d4acd07abcb1a7: locking/csd-lock: Switch from sched_clock() to ktime_get_mono_fast_ns() (2024-10-11 09:31:21 -0700)

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CSD-lock diagnostic updates for v6.13

This commit switches from sched_clock() to ktime_get_mono_fast_ns(), which
on x86 switches from the rdtsc instruction to the rdtscp instruction,
thus avoiding instruction reorderings that cause false-positive reports
of CSD-lock stalls of almost 2^46 nanoseconds. These false positives
are rare, but really are seen in the wild.

----------------------------------------------------------------
Paul E. McKenney (1):
locking/csd-lock: Switch from sched_clock() to ktime_get_mono_fast_ns()

kernel/smp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)