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-rw-r--r--debian/patches-rt/0203-mm-page_alloc-rt-friendly-per-cpu-pages.patch197
1 files changed, 197 insertions, 0 deletions
diff --git a/debian/patches-rt/0203-mm-page_alloc-rt-friendly-per-cpu-pages.patch b/debian/patches-rt/0203-mm-page_alloc-rt-friendly-per-cpu-pages.patch
new file mode 100644
index 000000000..8102e89d2
--- /dev/null
+++ b/debian/patches-rt/0203-mm-page_alloc-rt-friendly-per-cpu-pages.patch
@@ -0,0 +1,197 @@
+From 9f33cce55eb2594c4602653658103381064572d7 Mon Sep 17 00:00:00 2001
+From: Ingo Molnar <mingo@elte.hu>
+Date: Fri, 3 Jul 2009 08:29:37 -0500
+Subject: [PATCH 203/323] mm: page_alloc: rt-friendly per-cpu pages
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+rt-friendly per-cpu pages: convert the irqs-off per-cpu locking
+method into a preemptible, explicit-per-cpu-locks method.
+
+Contains fixes from:
+ Peter Zijlstra <a.p.zijlstra@chello.nl>
+ Thomas Gleixner <tglx@linutronix.de>
+
+Signed-off-by: Ingo Molnar <mingo@elte.hu>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ mm/page_alloc.c | 47 ++++++++++++++++++++++++++++-------------------
+ 1 file changed, 28 insertions(+), 19 deletions(-)
+
+diff --git a/mm/page_alloc.c b/mm/page_alloc.c
+index 508650843235..c5eb7d6844ae 100644
+--- a/mm/page_alloc.c
++++ b/mm/page_alloc.c
+@@ -61,6 +61,7 @@
+ #include <linux/hugetlb.h>
+ #include <linux/sched/rt.h>
+ #include <linux/sched/mm.h>
++#include <linux/local_lock.h>
+ #include <linux/page_owner.h>
+ #include <linux/kthread.h>
+ #include <linux/memcontrol.h>
+@@ -386,6 +387,13 @@ EXPORT_SYMBOL(nr_node_ids);
+ EXPORT_SYMBOL(nr_online_nodes);
+ #endif
+
++struct pa_lock {
++ local_lock_t l;
++};
++static DEFINE_PER_CPU(struct pa_lock, pa_lock) = {
++ .l = INIT_LOCAL_LOCK(l),
++};
++
+ int page_group_by_mobility_disabled __read_mostly;
+
+ #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+@@ -1543,11 +1551,11 @@ static void __free_pages_ok(struct page *page, unsigned int order,
+ return;
+
+ migratetype = get_pfnblock_migratetype(page, pfn);
+- local_irq_save(flags);
++ local_lock_irqsave(&pa_lock.l, flags);
+ __count_vm_events(PGFREE, 1 << order);
+ free_one_page(page_zone(page), page, pfn, order, migratetype,
+ fpi_flags);
+- local_irq_restore(flags);
++ local_unlock_irqrestore(&pa_lock.l, flags);
+ }
+
+ void __free_pages_core(struct page *page, unsigned int order)
+@@ -2961,13 +2969,13 @@ void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
+ int to_drain, batch;
+ LIST_HEAD(dst);
+
+- local_irq_save(flags);
++ local_lock_irqsave(&pa_lock.l, flags);
+ batch = READ_ONCE(pcp->batch);
+ to_drain = min(pcp->count, batch);
+ if (to_drain > 0)
+ isolate_pcp_pages(to_drain, pcp, &dst);
+
+- local_irq_restore(flags);
++ local_unlock_irqrestore(&pa_lock.l, flags);
+
+ if (to_drain > 0)
+ free_pcppages_bulk(zone, &dst, false);
+@@ -2989,7 +2997,7 @@ static void drain_pages_zone(unsigned int cpu, struct zone *zone)
+ LIST_HEAD(dst);
+ int count;
+
+- local_irq_save(flags);
++ local_lock_irqsave(&pa_lock.l, flags);
+ pset = per_cpu_ptr(zone->pageset, cpu);
+
+ pcp = &pset->pcp;
+@@ -2997,7 +3005,7 @@ static void drain_pages_zone(unsigned int cpu, struct zone *zone)
+ if (count)
+ isolate_pcp_pages(count, pcp, &dst);
+
+- local_irq_restore(flags);
++ local_unlock_irqrestore(&pa_lock.l, flags);
+
+ if (count)
+ free_pcppages_bulk(zone, &dst, false);
+@@ -3248,9 +3256,9 @@ void free_unref_page(struct page *page)
+ if (!free_unref_page_prepare(page, pfn))
+ return;
+
+- local_irq_save(flags);
++ local_lock_irqsave(&pa_lock.l, flags);
+ free_unref_page_commit(page, pfn, &dst);
+- local_irq_restore(flags);
++ local_unlock_irqrestore(&pa_lock.l, flags);
+ if (!list_empty(&dst))
+ free_pcppages_bulk(zone, &dst, false);
+ }
+@@ -3277,7 +3285,7 @@ void free_unref_page_list(struct list_head *list)
+ set_page_private(page, pfn);
+ }
+
+- local_irq_save(flags);
++ local_lock_irqsave(&pa_lock.l, flags);
+ list_for_each_entry_safe(page, next, list, lru) {
+ unsigned long pfn = page_private(page);
+ enum zone_type type;
+@@ -3292,12 +3300,12 @@ void free_unref_page_list(struct list_head *list)
+ * a large list of pages to free.
+ */
+ if (++batch_count == SWAP_CLUSTER_MAX) {
+- local_irq_restore(flags);
++ local_unlock_irqrestore(&pa_lock.l, flags);
+ batch_count = 0;
+- local_irq_save(flags);
++ local_lock_irqsave(&pa_lock.l, flags);
+ }
+ }
+- local_irq_restore(flags);
++ local_unlock_irqrestore(&pa_lock.l, flags);
+
+ for (i = 0; i < __MAX_NR_ZONES; ) {
+ struct page *page;
+@@ -3468,7 +3476,7 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone,
+ struct page *page;
+ unsigned long flags;
+
+- local_irq_save(flags);
++ local_lock_irqsave(&pa_lock.l, flags);
+ pcp = &this_cpu_ptr(zone->pageset)->pcp;
+ list = &pcp->lists[migratetype];
+ page = __rmqueue_pcplist(zone, migratetype, alloc_flags, pcp, list);
+@@ -3476,7 +3484,7 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone,
+ __count_zid_vm_events(PGALLOC, page_zonenum(page), 1);
+ zone_statistics(preferred_zone, zone);
+ }
+- local_irq_restore(flags);
++ local_unlock_irqrestore(&pa_lock.l, flags);
+ return page;
+ }
+
+@@ -3510,7 +3518,8 @@ struct page *rmqueue(struct zone *preferred_zone,
+ * allocate greater than order-1 page units with __GFP_NOFAIL.
+ */
+ WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
+- spin_lock_irqsave(&zone->lock, flags);
++ local_lock_irqsave(&pa_lock.l, flags);
++ spin_lock(&zone->lock);
+
+ do {
+ page = NULL;
+@@ -3536,7 +3545,7 @@ struct page *rmqueue(struct zone *preferred_zone,
+
+ __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
+ zone_statistics(preferred_zone, zone);
+- local_irq_restore(flags);
++ local_unlock_irqrestore(&pa_lock.l, flags);
+
+ out:
+ /* Separate test+clear to avoid unnecessary atomics */
+@@ -3549,7 +3558,7 @@ struct page *rmqueue(struct zone *preferred_zone,
+ return page;
+
+ failed:
+- local_irq_restore(flags);
++ local_unlock_irqrestore(&pa_lock.l, flags);
+ return NULL;
+ }
+
+@@ -8892,7 +8901,7 @@ void zone_pcp_reset(struct zone *zone)
+ struct per_cpu_pageset *pset;
+
+ /* avoid races with drain_pages() */
+- local_irq_save(flags);
++ local_lock_irqsave(&pa_lock.l, flags);
+ if (zone->pageset != &boot_pageset) {
+ for_each_online_cpu(cpu) {
+ pset = per_cpu_ptr(zone->pageset, cpu);
+@@ -8901,7 +8910,7 @@ void zone_pcp_reset(struct zone *zone)
+ free_percpu(zone->pageset);
+ zone->pageset = &boot_pageset;
+ }
+- local_irq_restore(flags);
++ local_unlock_irqrestore(&pa_lock.l, flags);
+ }
+
+ #ifdef CONFIG_MEMORY_HOTREMOVE
+--
+2.43.0
+