tmakin/ack-tegra
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

UPSTREAM: cpuidle, dt: Push RCU-idle into driver

Browse Source 
Doing RCU-idle outside the driver, only to then temporarily enable it
again before going idle is suboptimal.

Notably: this converts all dt_init_idle_driver() and
__CPU_PM_CPU_IDLE_ENTER() users for they are inextrably intertwined.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195540.068981667@infradead.org

Bug: 272060410
(cherry picked from commit 0c5ffc3d7b)
[alexey: bringing back the upstream change now that the root
problem for it being reverted is workarounded in exynos-cpupm
driver. The issue was that one of cpu pm notifiers via cpu_pm_enter()
didn't allow a CPU to transition into deeper idle state during reboot
which enabled the kernel to spin in a "loop" trying to put CPU in
this idle state continuously. This flow is no longer covered by
ct_cpuidle_{enter,exit}() section and RCU, if required, was waiting
for synchronization from these CPUs during reboot for a long time
using rcu_barrier().]
Signed-off-by: Alexey Klimov <klimova@google.com>

Change-Id: I452cc3c8779b76237b04a0afd5919d3e3d01809c
This commit is contained in:
Alexey Klimov
2023-03-27 13:17:36 +00:00
parent 98d1a250d3
commit bb9b96d96f
3 changed files with 11 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/acpi/processor_idle.c
+2
View File
@@ -1223,6 +1223,8 @@ static int acpi_processor_setup_lpi_states(struct acpi_processor *pr)
state->target_residency = lpi->min_residency;
if (lpi->arch_flags)
state->flags |= CPUIDLE_FLAG_TIMER_STOP;
if (i != 0 && lpi->entry_method == ACPI_CSTATE_FFH)
state->flags |= CPUIDLE_FLAG_RCU_IDLE;
state->enter = acpi_idle_lpi_enter;
drv->safe_state_index = i;
}
drivers/cpuidle/cpuidle-big_little.c
+8 -4
View File
@@ -64,7 +64,8 @@ static struct cpuidle_driver bl_idle_little_driver = {
.enter = bl_enter_powerdown,
.exit_latency = 700,
.target_residency = 2500,
.flags = CPUIDLE_FLAG_TIMER_STOP,
.flags = CPUIDLE_FLAG_TIMER_STOP |
CPUIDLE_FLAG_RCU_IDLE,
.name = "C1",
.desc = "ARM little-cluster power down",
},
@@ -85,7 +86,8 @@ static struct cpuidle_driver bl_idle_big_driver = {
.enter = bl_enter_powerdown,
.exit_latency = 500,
.target_residency = 2000,
.flags = CPUIDLE_FLAG_TIMER_STOP,
.flags = CPUIDLE_FLAG_TIMER_STOP |
CPUIDLE_FLAG_RCU_IDLE,
.name = "C1",
.desc = "ARM big-cluster power down",
},
@@ -120,15 +122,17 @@ static int notrace bl_powerdown_finisher(unsigned long arg)
* Called from the CPUidle framework to program the device to the
* specified target state selected by the governor.
*/
static int bl_enter_powerdown(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int idx)
static __cpuidle int bl_enter_powerdown(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int idx)
{
cpu_pm_enter();
ct_cpuidle_enter();
cpu_suspend(0, bl_powerdown_finisher);
/* signals the MCPM core that CPU is out of low power state */
mcpm_cpu_powered_up();
ct_cpuidle_exit();
cpu_pm_exit();
drivers/cpuidle/dt_idle_states.c
+1 -1
View File
@@ -77,7 +77,7 @@ static int init_state_node(struct cpuidle_state *idle_state,
if (err)
desc = state_node->name;
idle_state->flags = 0;
idle_state->flags = CPUIDLE_FLAG_RCU_IDLE;
if (of_property_read_bool(state_node, "local-timer-stop"))
idle_state->flags |= CPUIDLE_FLAG_TIMER_STOP;
/*