diff options
Diffstat (limited to 'debian/patches-rt/0003-mm-swap-Access-struct-pagevec-remotely.patch')
| -rw-r--r-- | debian/patches-rt/0003-mm-swap-Access-struct-pagevec-remotely.patch | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/debian/patches-rt/0003-mm-swap-Access-struct-pagevec-remotely.patch b/debian/patches-rt/0003-mm-swap-Access-struct-pagevec-remotely.patch new file mode 100644 index 000000000..5bc3c0f19 --- /dev/null +++ b/debian/patches-rt/0003-mm-swap-Access-struct-pagevec-remotely.patch @@ -0,0 +1,137 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 18 Apr 2019 11:09:06 +0200 +Subject: [PATCH 3/4] mm/swap: Access struct pagevec remotely +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.4/older/patches-5.4.3-rt1.tar.xz + +When the newly introduced static key would be enabled, struct pagevec is +locked during access. So it is possible to access it from a remote CPU. The +advantage is that the work can be done from the "requesting" CPU without +firing a worker on a remote CPU and waiting for it to complete the work. + +No functional change because static key is not enabled. + +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + mm/page_alloc.c | 19 ++++++++------ + mm/swap.c | 75 +++++++++++++++++++++++++++++++++----------------------- + 2 files changed, 57 insertions(+), 37 deletions(-) + +--- a/mm/page_alloc.c ++++ b/mm/page_alloc.c +@@ -2999,15 +2999,20 @@ void drain_all_pages(struct zone *zone) + cpumask_clear_cpu(cpu, &cpus_with_pcps); + } + +- for_each_cpu(cpu, &cpus_with_pcps) { +- struct pcpu_drain *drain = per_cpu_ptr(&pcpu_drain, cpu); ++ if (static_branch_likely(&use_pvec_lock)) { ++ for_each_cpu(cpu, &cpus_with_pcps) ++ drain_cpu_pages(cpu, zone); ++ } else { ++ for_each_cpu(cpu, &cpus_with_pcps) { ++ struct pcpu_drain *drain = per_cpu_ptr(&pcpu_drain, cpu); + +- drain->zone = zone; +- INIT_WORK(&drain->work, drain_local_pages_wq); +- queue_work_on(cpu, mm_percpu_wq, &drain->work); ++ drain->zone = zone; ++ INIT_WORK(&drain->work, drain_local_pages_wq); ++ queue_work_on(cpu, mm_percpu_wq, &drain->work); ++ } ++ for_each_cpu(cpu, &cpus_with_pcps) ++ flush_work(&per_cpu_ptr(&pcpu_drain, cpu)->work); + } +- for_each_cpu(cpu, &cpus_with_pcps) +- flush_work(&per_cpu_ptr(&pcpu_drain, cpu)->work); + + mutex_unlock(&pcpu_drain_mutex); + } +--- a/mm/swap.c ++++ b/mm/swap.c +@@ -834,39 +834,54 @@ static void lru_add_drain_per_cpu(struct + */ + void lru_add_drain_all(void) + { +- static DEFINE_MUTEX(lock); +- static struct cpumask has_work; +- int cpu; +- +- /* +- * Make sure nobody triggers this path before mm_percpu_wq is fully +- * initialized. +- */ +- if (WARN_ON(!mm_percpu_wq)) +- return; +- +- mutex_lock(&lock); +- cpumask_clear(&has_work); +- +- for_each_online_cpu(cpu) { +- struct work_struct *work = &per_cpu(lru_add_drain_work, cpu); +- +- if (pagevec_count(&per_cpu(lru_add_pvec.pvec, cpu)) || +- pagevec_count(&per_cpu(lru_rotate_pvecs.pvec, cpu)) || +- pagevec_count(&per_cpu(lru_deactivate_file_pvecs.pvec, cpu)) || +- pagevec_count(&per_cpu(lru_deactivate_pvecs.pvec, cpu)) || +- pagevec_count(&per_cpu(lru_lazyfree_pvecs.pvec, cpu)) || +- need_activate_page_drain(cpu)) { +- INIT_WORK(work, lru_add_drain_per_cpu); +- queue_work_on(cpu, mm_percpu_wq, work); +- cpumask_set_cpu(cpu, &has_work); ++ if (static_branch_likely(&use_pvec_lock)) { ++ int cpu; ++ ++ for_each_online_cpu(cpu) { ++ if (pagevec_count(&per_cpu(lru_add_pvec.pvec, cpu)) || ++ pagevec_count(&per_cpu(lru_rotate_pvecs.pvec, cpu)) || ++ pagevec_count(&per_cpu(lru_deactivate_file_pvecs.pvec, cpu)) || ++ pagevec_count(&per_cpu(lru_deactivate_pvecs.pvec, cpu)) || ++ pagevec_count(&per_cpu(lru_lazyfree_pvecs.pvec, cpu)) || ++ need_activate_page_drain(cpu)) { ++ lru_add_drain_cpu(cpu); ++ } ++ } ++ } else { ++ static DEFINE_MUTEX(lock); ++ static struct cpumask has_work; ++ int cpu; ++ ++ /* ++ * Make sure nobody triggers this path before mm_percpu_wq ++ * is fully initialized. ++ */ ++ if (WARN_ON(!mm_percpu_wq)) ++ return; ++ ++ mutex_lock(&lock); ++ cpumask_clear(&has_work); ++ ++ for_each_online_cpu(cpu) { ++ struct work_struct *work = &per_cpu(lru_add_drain_work, cpu); ++ ++ if (pagevec_count(&per_cpu(lru_add_pvec.pvec, cpu)) || ++ pagevec_count(&per_cpu(lru_rotate_pvecs.pvec, cpu)) || ++ pagevec_count(&per_cpu(lru_deactivate_file_pvecs.pvec, cpu)) || ++ pagevec_count(&per_cpu(lru_deactivate_pvecs.pvec, cpu)) || ++ pagevec_count(&per_cpu(lru_lazyfree_pvecs.pvec, cpu)) || ++ need_activate_page_drain(cpu)) { ++ INIT_WORK(work, lru_add_drain_per_cpu); ++ queue_work_on(cpu, mm_percpu_wq, work); ++ cpumask_set_cpu(cpu, &has_work); ++ } + } +- } + +- for_each_cpu(cpu, &has_work) +- flush_work(&per_cpu(lru_add_drain_work, cpu)); ++ for_each_cpu(cpu, &has_work) ++ flush_work(&per_cpu(lru_add_drain_work, cpu)); + +- mutex_unlock(&lock); ++ mutex_unlock(&lock); ++ } + } + #else + void lru_add_drain_all(void) |