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rcu: Eliminate check_cpu_stall() duplicate code

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The code and comments of self-detected and other-detected RCU CPU stall
warnings are identical except the output function.  This commit therefore
refactors so as to consolidate the duplicate code.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This commit is contained in:
Zhen Lei 2023-07-24 10:26:51 +08:00 committed by Frederic Weisbecker
parent f3efe02fd5
commit 243d5ab344
1 changed files with 15 additions and 27 deletions
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42
kernel/rcu/tree_stall.h
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@ -711,7 +711,7 @@ static void print_cpu_stall(unsigned long gps)
static void check_cpu_stall(struct rcu_data *rdp)
{
bool didstall = false;
bool self_detected;
unsigned long gs1;
unsigned long gs2;
unsigned long gps;
@ -758,10 +758,10 @@ static void check_cpu_stall(struct rcu_data *rdp)
return; /* No stall or GP completed since entering function. */
rnp = rdp->mynode;
jn = jiffies + ULONG_MAX / 2;
self_detected = READ_ONCE(rnp->qsmask) & rdp->grpmask;
if (rcu_gp_in_progress() &&
(READ_ONCE(rnp->qsmask) & rdp->grpmask) &&
(self_detected || ULONG_CMP_GE(j, js + RCU_STALL_RAT_DELAY)) &&
cmpxchg(&rcu_state.jiffies_stall, js, jn) == js) {
/*
* If a virtual machine is stopped by the host it can look to
* the watchdog like an RCU stall. Check to see if the host
@ -770,33 +770,21 @@ static void check_cpu_stall(struct rcu_data *rdp)
if (kvm_check_and_clear_guest_paused())
return;
/* We haven't checked in, so go dump stack. */
print_cpu_stall(gps);
if (self_detected) {
/* We haven't checked in, so go dump stack. */
print_cpu_stall(gps);
} else {
/* They had a few time units to dump stack, so complain. */
print_other_cpu_stall(gs2, gps);
}
if (READ_ONCE(rcu_cpu_stall_ftrace_dump))
rcu_ftrace_dump(DUMP_ALL);
didstall = true;
} else if (rcu_gp_in_progress() &&
ULONG_CMP_GE(j, js + RCU_STALL_RAT_DELAY) &&
cmpxchg(&rcu_state.jiffies_stall, js, jn) == js) {
/*
* If a virtual machine is stopped by the host it can look to
* the watchdog like an RCU stall. Check to see if the host
* stopped the vm.
*/
if (kvm_check_and_clear_guest_paused())
return;
/* They had a few time units to dump stack, so complain. */
print_other_cpu_stall(gs2, gps);
if (READ_ONCE(rcu_cpu_stall_ftrace_dump))
rcu_ftrace_dump(DUMP_ALL);
didstall = true;
}
if (didstall && READ_ONCE(rcu_state.jiffies_stall) == jn) {
jn = jiffies + 3 * rcu_jiffies_till_stall_check() + 3;
WRITE_ONCE(rcu_state.jiffies_stall, jn);
if (READ_ONCE(rcu_state.jiffies_stall) == jn) {
jn = jiffies + 3 * rcu_jiffies_till_stall_check() + 3;
WRITE_ONCE(rcu_state.jiffies_stall, jn);
}
}
}