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| author | Alexei Starovoitov <ast@kernel.org> | 2020-09-23 19:32:09 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-09-23 19:32:09 -0700 |
| commit | 182bf3f3ddb607a0715b73a8396af1fce0945c14 (patch) | |
| tree | d882c33f47f1aff70a14ffd4ce9a997e0d710d40 /include/linux/rcupdate_trace.h | |
| parent | f00f2f7fe86036a586e26bd55ad86310477199a3 (diff) | |
| parent | f747c7e15d7bc71a967a94ceda686cf2460b69e8 (diff) | |
| download | lwn-182bf3f3ddb607a0715b73a8396af1fce0945c14.tar.gz lwn-182bf3f3ddb607a0715b73a8396af1fce0945c14.zip | |
Merge branch 'rtt-speedup.2020.09.16a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into bpf-next
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include/linux/rcupdate_trace.h')
| -rw-r--r-- | include/linux/rcupdate_trace.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/rcupdate_trace.h b/include/linux/rcupdate_trace.h index aaaac8ac927c..3e7919fc5f34 100644 --- a/include/linux/rcupdate_trace.h +++ b/include/linux/rcupdate_trace.h @@ -50,6 +50,7 @@ static inline void rcu_read_lock_trace(void) struct task_struct *t = current; WRITE_ONCE(t->trc_reader_nesting, READ_ONCE(t->trc_reader_nesting) + 1); + barrier(); if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB) && t->trc_reader_special.b.need_mb) smp_mb(); // Pairs with update-side barriers @@ -72,6 +73,9 @@ static inline void rcu_read_unlock_trace(void) rcu_lock_release(&rcu_trace_lock_map); nesting = READ_ONCE(t->trc_reader_nesting) - 1; + barrier(); // Critical section before disabling. + // Disable IPI-based setting of .need_qs. + WRITE_ONCE(t->trc_reader_nesting, INT_MIN); if (likely(!READ_ONCE(t->trc_reader_special.s)) || nesting) { WRITE_ONCE(t->trc_reader_nesting, nesting); return; // We assume shallow reader nesting. |