diff options
Diffstat (limited to 'mm/vmstat.c')
| -rw-r--r-- | mm/vmstat.c | 73 |
1 files changed, 56 insertions, 17 deletions
diff --git a/mm/vmstat.c b/mm/vmstat.c index a7ed56ac4c0b..8ce2620344b2 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -204,7 +204,7 @@ int calculate_normal_threshold(struct zone *zone) * * Some sample thresholds: * - * Threshold Processors (fls) Zonesize fls(mem+1) + * Threshold Processors (fls) Zonesize fls(mem)+1 * ------------------------------------------------------------------ * 8 1 1 0.9-1 GB 4 * 16 2 2 0.9-1 GB 4 @@ -319,6 +319,16 @@ void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item, long x; long t; + /* + * Accurate vmstat updates require a RMW. On !PREEMPT_RT kernels, + * atomicity is provided by IRQs being disabled -- either explicitly + * or via local_lock_irq. On PREEMPT_RT, local_lock_irq only disables + * CPU migrations and preemption potentially corrupts a counter so + * disable preemption. + */ + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_disable(); + x = delta + __this_cpu_read(*p); t = __this_cpu_read(pcp->stat_threshold); @@ -328,6 +338,9 @@ void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item, x = 0; } __this_cpu_write(*p, x); + + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_enable(); } EXPORT_SYMBOL(__mod_zone_page_state); @@ -350,6 +363,10 @@ void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item, delta >>= PAGE_SHIFT; } + /* See __mod_node_page_state */ + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_disable(); + x = delta + __this_cpu_read(*p); t = __this_cpu_read(pcp->stat_threshold); @@ -359,6 +376,9 @@ void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item, x = 0; } __this_cpu_write(*p, x); + + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_enable(); } EXPORT_SYMBOL(__mod_node_page_state); @@ -391,6 +411,10 @@ void __inc_zone_state(struct zone *zone, enum zone_stat_item item) s8 __percpu *p = pcp->vm_stat_diff + item; s8 v, t; + /* See __mod_node_page_state */ + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_disable(); + v = __this_cpu_inc_return(*p); t = __this_cpu_read(pcp->stat_threshold); if (unlikely(v > t)) { @@ -399,6 +423,9 @@ void __inc_zone_state(struct zone *zone, enum zone_stat_item item) zone_page_state_add(v + overstep, zone, item); __this_cpu_write(*p, -overstep); } + + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_enable(); } void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item) @@ -409,6 +436,10 @@ void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item) VM_WARN_ON_ONCE(vmstat_item_in_bytes(item)); + /* See __mod_node_page_state */ + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_disable(); + v = __this_cpu_inc_return(*p); t = __this_cpu_read(pcp->stat_threshold); if (unlikely(v > t)) { @@ -417,6 +448,9 @@ void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item) node_page_state_add(v + overstep, pgdat, item); __this_cpu_write(*p, -overstep); } + + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_enable(); } void __inc_zone_page_state(struct page *page, enum zone_stat_item item) @@ -437,6 +471,10 @@ void __dec_zone_state(struct zone *zone, enum zone_stat_item item) s8 __percpu *p = pcp->vm_stat_diff + item; s8 v, t; + /* See __mod_node_page_state */ + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_disable(); + v = __this_cpu_dec_return(*p); t = __this_cpu_read(pcp->stat_threshold); if (unlikely(v < - t)) { @@ -445,6 +483,9 @@ void __dec_zone_state(struct zone *zone, enum zone_stat_item item) zone_page_state_add(v - overstep, zone, item); __this_cpu_write(*p, overstep); } + + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_enable(); } void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item) @@ -455,6 +496,10 @@ void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item) VM_WARN_ON_ONCE(vmstat_item_in_bytes(item)); + /* See __mod_node_page_state */ + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_disable(); + v = __this_cpu_dec_return(*p); t = __this_cpu_read(pcp->stat_threshold); if (unlikely(v < - t)) { @@ -463,6 +508,9 @@ void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item) node_page_state_add(v - overstep, pgdat, item); __this_cpu_write(*p, overstep); } + + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_enable(); } void __dec_zone_page_state(struct page *page, enum zone_stat_item item) @@ -1217,6 +1265,8 @@ const char * const vmstat_text[] = { "pgreuse", "pgsteal_kswapd", "pgsteal_direct", + "pgdemote_kswapd", + "pgdemote_direct", "pgscan_kswapd", "pgscan_direct", "pgscan_direct_throttle", @@ -1452,7 +1502,7 @@ static void pagetypeinfo_showfree_print(struct seq_file *m, } /* Print out the free pages at each order for each migatetype */ -static int pagetypeinfo_showfree(struct seq_file *m, void *arg) +static void pagetypeinfo_showfree(struct seq_file *m, void *arg) { int order; pg_data_t *pgdat = (pg_data_t *)arg; @@ -1464,8 +1514,6 @@ static int pagetypeinfo_showfree(struct seq_file *m, void *arg) seq_putc(m, '\n'); walk_zones_in_node(m, pgdat, true, false, pagetypeinfo_showfree_print); - - return 0; } static void pagetypeinfo_showblockcount_print(struct seq_file *m, @@ -1501,7 +1549,7 @@ static void pagetypeinfo_showblockcount_print(struct seq_file *m, } /* Print out the number of pageblocks for each migratetype */ -static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg) +static void pagetypeinfo_showblockcount(struct seq_file *m, void *arg) { int mtype; pg_data_t *pgdat = (pg_data_t *)arg; @@ -1512,8 +1560,6 @@ static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg) seq_putc(m, '\n'); walk_zones_in_node(m, pgdat, true, false, pagetypeinfo_showblockcount_print); - - return 0; } /* @@ -1874,11 +1920,6 @@ static void vmstat_update(struct work_struct *w) } /* - * 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 - * invoked when tick processing is not active. - */ -/* * Check if the diffs for a certain cpu indicate that * an update is needed. */ @@ -1894,17 +1935,15 @@ static bool need_update(int cpu) /* * The fast way of checking if there are any vmstat diffs. */ - if (memchr_inv(pzstats->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS * - sizeof(pzstats->vm_stat_diff[0]))) + 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, NR_VM_NODE_STAT_ITEMS * - sizeof(n->vm_node_stat_diff[0]))) - return true; + if (memchr_inv(n->vm_node_stat_diff, 0, sizeof(n->vm_node_stat_diff))) + return true; } return false; } |