Messages in this thread Patch in this message | | | Date | Fri, 04 Feb 2022 14:35:44 -0300 | From | Marcelo Tosatti <> | Subject | [patch v11 07/13] task isolation: sync vmstats conditional on changes |
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Rather than syncing VM-stats on every return to userspace (or VM-entry), keep track of changes through a per-CPU bool.
This improves performance when enabling task isolated for vcpu VMs.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
--- v11: - Add TIF_TASK_ISOL bit to thread info flags and use it to decide whether to perform task isolation work on return to userspace
include/linux/vmstat.h | 13 ++++++++++++- mm/vmstat.c | 29 ++++++++++++++++++++++++++++- 2 files changed, 40 insertions(+), 2 deletions(-)
Index: linux-2.6/include/linux/vmstat.h =================================================================== --- linux-2.6.orig/include/linux/vmstat.h +++ linux-2.6/include/linux/vmstat.h @@ -22,7 +22,18 @@ int sysctl_vm_numa_stat_handler(struct c #endif #if defined(CONFIG_SMP) && defined(CONFIG_TASK_ISOLATION) -void sync_vmstat(void); +DECLARE_PER_CPU_ALIGNED(bool, vmstat_dirty); + +extern struct static_key vmstat_sync_enabled; + +void __sync_vmstat(void); +static inline void sync_vmstat(void) +{ + if (static_key_false(&vmstat_sync_enabled)) + __sync_vmstat(); +} + +void init_sync_vmstat(void); #else static inline void sync_vmstat(void) { Index: linux-2.6/mm/vmstat.c =================================================================== --- linux-2.6.orig/mm/vmstat.c +++ linux-2.6/mm/vmstat.c @@ -334,6 +334,31 @@ void set_pgdat_percpu_threshold(pg_data_ } } +#ifdef CONFIG_TASK_ISOLATION +struct static_key vmstat_sync_enabled; +DEFINE_PER_CPU_ALIGNED(bool, vmstat_dirty); + +static inline void mark_vmstat_dirty(void) +{ + if (!static_key_false(&vmstat_sync_enabled)) + return; + + raw_cpu_write(vmstat_dirty, true); + set_thread_flag(TIF_TASK_ISOL); +} + +void init_sync_vmstat(void) +{ + raw_cpu_write(vmstat_dirty, true); + set_thread_flag(TIF_TASK_ISOL); +} +EXPORT_SYMBOL_GPL(vmstat_dirty); +#else +static inline void mark_vmstat_dirty(void) +{ +} +#endif + /* * For use when we know that interrupts are disabled, * or when we know that preemption is disabled and that @@ -366,6 +391,7 @@ void __mod_zone_page_state(struct zone * x = 0; } __this_cpu_write(*p, x); + mark_vmstat_dirty(); if (IS_ENABLED(CONFIG_PREEMPT_RT)) preempt_enable(); @@ -404,6 +430,7 @@ void __mod_node_page_state(struct pglist x = 0; } __this_cpu_write(*p, x); + mark_vmstat_dirty(); if (IS_ENABLED(CONFIG_PREEMPT_RT)) preempt_enable(); @@ -602,6 +629,7 @@ static inline void mod_zone_state(struct if (z) zone_page_state_add(z, zone, item); + mark_vmstat_dirty(); } void mod_zone_page_state(struct zone *zone, enum zone_stat_item item, @@ -670,6 +698,7 @@ static inline void mod_node_state(struct if (z) node_page_state_add(z, pgdat, item); + mark_vmstat_dirty(); } void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item, @@ -1087,6 +1116,7 @@ static void fill_contig_page_info(struct info->free_blocks_suitable += blocks << (order - suitable_order); } + mark_vmstat_dirty(); } /* @@ -1443,6 +1473,7 @@ static void walk_zones_in_node(struct se if (!nolock) spin_unlock_irqrestore(&zone->lock, flags); } + mark_vmstat_dirty(); } #endif @@ -1512,6 +1543,7 @@ static void pagetypeinfo_showfree_print( } seq_putc(m, '\n'); } + mark_vmstat_dirty(); } /* Print out the free pages at each order for each migatetype */ @@ -1932,6 +1964,7 @@ static void vmstat_update(struct work_st this_cpu_ptr(&vmstat_work), round_jiffies_relative(sysctl_stat_interval)); } + mark_vmstat_dirty(); } /* @@ -2019,13 +2052,14 @@ static void vmstat_shepherd(struct work_ } #ifdef CONFIG_TASK_ISOLATION -void sync_vmstat(void) +void __sync_vmstat(void) { int cpu; cpu = get_cpu(); refresh_cpu_vm_stats(false); + raw_cpu_write(vmstat_dirty, false); put_cpu(); /*
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