twx-linux/kernel
John Stultz d179ebed94 locking/rwsem: Add __always_inline annotation to __down_write_common() and inlined callers
[ Upstream commit e81859fe64ad42dccefe134d1696e0635f78d763 ]

Apparently despite it being marked inline, the compiler
may not inline __down_write_common() which makes it difficult
to identify the cause of lock contention, as the wchan of the
blocked function will always be listed as __down_write_common().

So add __always_inline annotation to the common function (as
well as the inlined helper callers) to force it to be inlined
so a more useful blocking function will be listed (via wchan).

This mirrors commit 92cc5d00a431 ("locking/rwsem: Add
__always_inline annotation to __down_read_common() and inlined
callers") which did the same for __down_read_common.

I sort of worry that I'm playing wack-a-mole here, and talking
with compiler people, they tell me inline means nothing, which
makes me want to cry a little. So I'm wondering if we need to
replace all the inlines with __always_inline, or remove them
because either we mean something by it, or not.

Fixes: c995e638ccbb ("locking/rwsem: Fold __down_{read,write}*()")
Reported-by: Tim Murray <timmurray@google.com>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lkml.kernel.org/r/20240709060831.495366-1-jstultz@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-03 08:53:42 +02:00
..
bpf bpf: Fail bpf_timer_cancel when callback is being cancelled 2024-07-18 13:21:14 +02:00
cgroup cgroup/cpuset: Prevent UAF in proc_cpuset_show() 2024-08-03 08:53:22 +02:00
configs
debug
dma
entry
events perf: Fix default aux_watermark calculation 2024-08-03 08:53:41 +02:00
futex
gcov
irq
kcsan
livepatch
locking locking/rwsem: Add __always_inline annotation to __down_write_common() and inlined callers 2024-08-03 08:53:42 +02:00
module
power
printk
rcu rcu/tasks: Fix stale task snaphot for Tasks Trace 2024-08-03 08:53:20 +02:00
sched rcu/tasks: Fix stale task snaphot for Tasks Trace 2024-08-03 08:53:20 +02:00
time
trace
.gitignore
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