Re: [PATCH v13 09/14] unwind deferred: Use SRCU unwind_deferred_task_work()
From: Peter Zijlstra <peterz@infradead.org>
Date: 2025-07-14 13:56:49
Also in:
bpf, lkml
On Mon, Jul 07, 2025 at 09:22:48PM -0400, Steven Rostedt wrote:
quoted hunk ↗ jump to hunk
@@ -143,6 +144,7 @@ static void unwind_deferred_task_work(struct callback_head *head) struct unwind_stacktrace trace; struct unwind_work *work; u64 cookie; + int idx; if (WARN_ON_ONCE(!local_read(&info->pending))) return;@@ -161,13 +163,15 @@ static void unwind_deferred_task_work(struct callback_head *head) cookie = info->id.id; - guard(mutex)(&callback_mutex); - list_for_each_entry(work, &callbacks, list) { + idx = srcu_read_lock(&unwind_srcu); + list_for_each_entry_srcu(work, &callbacks, list, + srcu_read_lock_held(&unwind_srcu)) { if (test_bit(work->bit, &info->unwind_mask)) { work->func(work, &trace, cookie); clear_bit(work->bit, &info->unwind_mask); } } + srcu_read_unlock(&unwind_srcu, idx); }
Please; something like so:
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h@@ -524,4 +524,9 @@ DEFINE_LOCK_GUARD_1(srcu, struct srcu_st srcu_read_unlock(_T->lock, _T->idx), int idx) +DEFINE_LOCK_GUARD_1(srcu_lite, struct srcu_struct, + _T->idx = srcu_read_lock_lite(_T->lock), + srcu_read_unlock_lite(_T->lock, _T->idx), + int idx) + #endif --- a/kernel/unwind/deferred.c +++ b/kernel/unwind/deferred.c
@@ -165,7 +165,7 @@ static void unwind_deferred_task_work(st cookie = info->id.id; - guard(mutex)(&callback_mutex); + guard(srcu_lite)(&unwind_srcu); list_for_each_entry(work, &callbacks, list) { work->func(work, &trace, cookie); }