This patch will now use the previously introduced CPU-specific variable
namely vmstat_dirty to indicate if a vmstat differential/or imbalance is
present for a given CPU. So, at the appropriate time, vmstat processing can
be initiated. The hope is that this particular approach is "cheaper" when
compared to need_update(). The idea is based on Marcelo's patch [1].
[1]: https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Aaron Tomlin <[email protected]>
---
mm/vmstat.c | 48 ++++++++++++++----------------------------------
1 file changed, 14 insertions(+), 34 deletions(-)
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 24c67b2e58fd..472175642bd9 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -383,6 +383,7 @@ void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
x = 0;
}
__this_cpu_write(*p, x);
+ vmstat_mark_dirty();
if (IS_ENABLED(CONFIG_PREEMPT_RT))
preempt_enable();
@@ -421,6 +422,7 @@ void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
x = 0;
}
__this_cpu_write(*p, x);
+ vmstat_mark_dirty();
if (IS_ENABLED(CONFIG_PREEMPT_RT))
preempt_enable();
@@ -619,6 +621,7 @@ static inline void mod_zone_state(struct zone *zone,
if (z)
zone_page_state_add(z, zone, item);
+ vmstat_mark_dirty();
}
void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
@@ -687,6 +690,7 @@ static inline void mod_node_state(struct pglist_data *pgdat,
if (z)
node_page_state_add(z, pgdat, item);
+ vmstat_mark_dirty();
}
void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
@@ -841,6 +845,14 @@ static int refresh_cpu_vm_stats(bool do_pagesets)
int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
int changes = 0;
+ /*
+ * Clear vmstat_dirty before clearing the percpu vmstats.
+ * If interrupts are enabled, it is possible that an interrupt
+ * or another task modifies a percpu vmstat, which will
+ * set vmstat_dirty to true.
+ */
+ vmstat_clear_dirty();
+
for_each_populated_zone(zone) {
struct per_cpu_zonestat __percpu *pzstats = zone->per_cpu_zonestats;
#ifdef CONFIG_NUMA
@@ -1971,35 +1983,6 @@ static void vmstat_update(struct work_struct *w)
}
}
-/*
- * Check if the diffs for a certain cpu indicate that
- * an update is needed.
- */
-static bool need_update(int cpu)
-{
- pg_data_t *last_pgdat = NULL;
- struct zone *zone;
-
- for_each_populated_zone(zone) {
- struct per_cpu_zonestat *pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
- struct per_cpu_nodestat *n;
-
- /*
- * The fast way of checking if there are any vmstat diffs.
- */
- if (memchr_inv(pzstats->vm_stat_diff, 0, sizeof(pzstats->vm_stat_diff)))
- return true;
-
- if (last_pgdat == zone->zone_pgdat)
- continue;
- last_pgdat = zone->zone_pgdat;
- n = per_cpu_ptr(zone->zone_pgdat->per_cpu_nodestats, cpu);
- if (memchr_inv(n->vm_node_stat_diff, 0, sizeof(n->vm_node_stat_diff)))
- return true;
- }
- return false;
-}
-
/*
* Switch off vmstat processing and then fold all the remaining differentials
* until the diffs stay at zero. The function is used by NOHZ and can only be
@@ -2010,10 +1993,7 @@ void quiet_vmstat(void)
if (system_state != SYSTEM_RUNNING)
return;
- if (!delayed_work_pending(this_cpu_ptr(&vmstat_work)))
- return;
-
- if (!need_update(smp_processor_id()))
+ if (!is_vmstat_dirty())
return;
/*
@@ -2044,7 +2024,7 @@ static void vmstat_shepherd(struct work_struct *w)
for_each_online_cpu(cpu) {
struct delayed_work *dw = &per_cpu(vmstat_work, cpu);
- if (!delayed_work_pending(dw) && need_update(cpu))
+ if (!delayed_work_pending(dw) && per_cpu(vmstat_dirty, cpu))
queue_delayed_work_on(cpu, mm_percpu_wq, dw, 0);
cond_resched();
--
2.37.1
Hi Aaron,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[also build test WARNING on v6.0-rc7]
[cannot apply to tip/timers/nohz]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Aaron-Tomlin/Ensure-quiet_vmstat-is-called-when-the-idle-tick-was-stopped-too/20220924-232617
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git a63f2e7cb1107ab124f80407e5eb8579c04eb7a9
config: loongarch-randconfig-s031-20220925
compiler: loongarch64-linux-gcc (GCC) 12.1.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# apt-get install sparse
# sparse version: v0.6.4-39-gce1a6720-dirty
# https://github.com/intel-lab-lkp/linux/commit/7228847514aa665d6745a03c37dbf180b7ac8743
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Aaron-Tomlin/Ensure-quiet_vmstat-is-called-when-the-idle-tick-was-stopped-too/20220924-232617
git checkout 7228847514aa665d6745a03c37dbf180b7ac8743
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=loongarch SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
sparse warnings: (new ones prefixed by >>)
>> mm/vmstat.c:202:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:202:9: sparse: expected void *ptr
mm/vmstat.c:202:9: sparse: got bool [noderef] __percpu *
>> mm/vmstat.c:202:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:202:9: sparse: expected void *ptr
mm/vmstat.c:202:9: sparse: got bool [noderef] __percpu *
>> mm/vmstat.c:202:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:202:9: sparse: expected void *ptr
mm/vmstat.c:202:9: sparse: got bool [noderef] __percpu *
>> mm/vmstat.c:202:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:202:9: sparse: expected void *ptr
mm/vmstat.c:202:9: sparse: got bool [noderef] __percpu *
>> mm/vmstat.c:202:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:202:9: sparse: expected void *ptr
mm/vmstat.c:202:9: sparse: got bool [noderef] __percpu *
>> mm/vmstat.c:202:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:202:9: sparse: expected void *ptr
mm/vmstat.c:202:9: sparse: got bool [noderef] __percpu *
>> mm/vmstat.c:202:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:202:9: sparse: expected void *ptr
mm/vmstat.c:202:9: sparse: got bool [noderef] __percpu *
>> mm/vmstat.c:202:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:202:9: sparse: expected void *ptr
mm/vmstat.c:202:9: sparse: got bool [noderef] __percpu *
mm/vmstat.c:207:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:207:9: sparse: expected void *ptr
mm/vmstat.c:207:9: sparse: got bool [noderef] __percpu *
mm/vmstat.c:207:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:207:9: sparse: expected void *ptr
mm/vmstat.c:207:9: sparse: got bool [noderef] __percpu *
mm/vmstat.c:207:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:207:9: sparse: expected void *ptr
mm/vmstat.c:207:9: sparse: got bool [noderef] __percpu *
mm/vmstat.c:207:9: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:207:9: sparse: expected void *ptr
mm/vmstat.c:207:9: sparse: got bool [noderef] __percpu *
mm/vmstat.c:1493:47: sparse: sparse: context imbalance in 'walk_zones_in_node' - unexpected unlock
mm/vmstat.c:212:16: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:212:16: sparse: expected void *ptr
mm/vmstat.c:212:16: sparse: got bool [noderef] __percpu *
mm/vmstat.c:212:16: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:212:16: sparse: expected void *ptr
mm/vmstat.c:212:16: sparse: got bool [noderef] __percpu *
mm/vmstat.c:212:16: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:212:16: sparse: expected void *ptr
mm/vmstat.c:212:16: sparse: got bool [noderef] __percpu *
mm/vmstat.c:212:16: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void *ptr @@ got bool [noderef] __percpu * @@
mm/vmstat.c:212:16: sparse: expected void *ptr
mm/vmstat.c:212:16: sparse: got bool [noderef] __percpu *
vim +202 mm/vmstat.c
83bc5e1c6ef29d Aaron Tomlin 2022-09-24 199
83bc5e1c6ef29d Aaron Tomlin 2022-09-24 200 static inline void vmstat_mark_dirty(void)
83bc5e1c6ef29d Aaron Tomlin 2022-09-24 201 {
83bc5e1c6ef29d Aaron Tomlin 2022-09-24 @202 this_cpu_write(vmstat_dirty, true);
83bc5e1c6ef29d Aaron Tomlin 2022-09-24 203 }
83bc5e1c6ef29d Aaron Tomlin 2022-09-24 204
--
0-DAY CI Kernel Test Service
https://01.org/lkp