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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2022-04-01 11:28:33 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-04-01 11:46:09 -0700
commitadb11e78c5dc5e26774acb05f983da36447f7911 (patch)
treebacf697b157f86712edffebbfd7c08aa7d83e966
parent577e9846f8a9e7b09cd356ae0d59a66e19402e8b (diff)
mm/munlock: protect the per-CPU pagevec by a local_lock_t
The access to mlock_pvec is protected by disabling preemption via get_cpu_var() or implicit by having preemption disabled by the caller (in mlock_page_drain() case). This breaks on PREEMPT_RT since folio_lruvec_lock_irq() acquires a sleeping lock in this section. Create struct mlock_pvec which consits of the local_lock_t and the pagevec. Acquire the local_lock() before accessing the per-CPU pagevec. Replace mlock_page_drain() with a _local() version which is invoked on the local CPU and acquires the local_lock_t and a _remote() version which uses the pagevec from a remote CPU which offline. Link: https://lkml.kernel.org/r/YjizWi9IY0mpvIfb@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Hugh Dickins <hughd@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox <willy@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/internal.h6
-rw-r--r--mm/migrate.c2
-rw-r--r--mm/mlock.c46
-rw-r--r--mm/page_alloc.c1
-rw-r--r--mm/rmap.c4
-rw-r--r--mm/swap.c4
6 files changed, 47 insertions, 16 deletions
diff --git a/mm/internal.h b/mm/internal.h
index 58dc6adc19c5..cf16280ce132 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -456,7 +456,8 @@ static inline void munlock_vma_page(struct page *page,
}
void mlock_new_page(struct page *page);
bool need_mlock_page_drain(int cpu);
-void mlock_page_drain(int cpu);
+void mlock_page_drain_local(void);
+void mlock_page_drain_remote(int cpu);
extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
@@ -539,7 +540,8 @@ static inline void munlock_vma_page(struct page *page,
struct vm_area_struct *vma, bool compound) { }
static inline void mlock_new_page(struct page *page) { }
static inline bool need_mlock_page_drain(int cpu) { return false; }
-static inline void mlock_page_drain(int cpu) { }
+static inline void mlock_page_drain_local(void) { }
+static inline void mlock_page_drain_remote(int cpu) { }
static inline void vunmap_range_noflush(unsigned long start, unsigned long end)
{
}
diff --git a/mm/migrate.c b/mm/migrate.c
index 3d60823afd2d..de175e2fdba5 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -246,7 +246,7 @@ static bool remove_migration_pte(struct folio *folio,
set_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte);
}
if (vma->vm_flags & VM_LOCKED)
- mlock_page_drain(smp_processor_id());
+ mlock_page_drain_local();
trace_remove_migration_pte(pvmw.address, pte_val(pte),
compound_order(new));
diff --git a/mm/mlock.c b/mm/mlock.c
index 529fbc1f27c8..716caf851043 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -28,7 +28,14 @@
#include "internal.h"
-static DEFINE_PER_CPU(struct pagevec, mlock_pvec);
+struct mlock_pvec {
+ local_lock_t lock;
+ struct pagevec vec;
+};
+
+static DEFINE_PER_CPU(struct mlock_pvec, mlock_pvec) = {
+ .lock = INIT_LOCAL_LOCK(lock),
+};
bool can_do_mlock(void)
{
@@ -203,18 +210,30 @@ static void mlock_pagevec(struct pagevec *pvec)
pagevec_reinit(pvec);
}
-void mlock_page_drain(int cpu)
+void mlock_page_drain_local(void)
+{
+ struct pagevec *pvec;
+
+ local_lock(&mlock_pvec.lock);
+ pvec = this_cpu_ptr(&mlock_pvec.vec);
+ if (pagevec_count(pvec))
+ mlock_pagevec(pvec);
+ local_unlock(&mlock_pvec.lock);
+}
+
+void mlock_page_drain_remote(int cpu)
{
struct pagevec *pvec;
- pvec = &per_cpu(mlock_pvec, cpu);
+ WARN_ON_ONCE(cpu_online(cpu));
+ pvec = &per_cpu(mlock_pvec.vec, cpu);
if (pagevec_count(pvec))
mlock_pagevec(pvec);
}
bool need_mlock_page_drain(int cpu)
{
- return pagevec_count(&per_cpu(mlock_pvec, cpu));
+ return pagevec_count(&per_cpu(mlock_pvec.vec, cpu));
}
/**
@@ -223,7 +242,10 @@ bool need_mlock_page_drain(int cpu)
*/
void mlock_folio(struct folio *folio)
{
- struct pagevec *pvec = &get_cpu_var(mlock_pvec);
+ struct pagevec *pvec;
+
+ local_lock(&mlock_pvec.lock);
+ pvec = this_cpu_ptr(&mlock_pvec.vec);
if (!folio_test_set_mlocked(folio)) {
int nr_pages = folio_nr_pages(folio);
@@ -236,7 +258,7 @@ void mlock_folio(struct folio *folio)
if (!pagevec_add(pvec, mlock_lru(&folio->page)) ||
folio_test_large(folio) || lru_cache_disabled())
mlock_pagevec(pvec);
- put_cpu_var(mlock_pvec);
+ local_unlock(&mlock_pvec.lock);
}
/**
@@ -245,9 +267,11 @@ void mlock_folio(struct folio *folio)
*/
void mlock_new_page(struct page *page)
{
- struct pagevec *pvec = &get_cpu_var(mlock_pvec);
+ struct pagevec *pvec;
int nr_pages = thp_nr_pages(page);
+ local_lock(&mlock_pvec.lock);
+ pvec = this_cpu_ptr(&mlock_pvec.vec);
SetPageMlocked(page);
mod_zone_page_state(page_zone(page), NR_MLOCK, nr_pages);
__count_vm_events(UNEVICTABLE_PGMLOCKED, nr_pages);
@@ -256,7 +280,7 @@ void mlock_new_page(struct page *page)
if (!pagevec_add(pvec, mlock_new(page)) ||
PageHead(page) || lru_cache_disabled())
mlock_pagevec(pvec);
- put_cpu_var(mlock_pvec);
+ local_unlock(&mlock_pvec.lock);
}
/**
@@ -265,8 +289,10 @@ void mlock_new_page(struct page *page)
*/
void munlock_page(struct page *page)
{
- struct pagevec *pvec = &get_cpu_var(mlock_pvec);
+ struct pagevec *pvec;
+ local_lock(&mlock_pvec.lock);
+ pvec = this_cpu_ptr(&mlock_pvec.vec);
/*
* TestClearPageMlocked(page) must be left to __munlock_page(),
* which will check whether the page is multiply mlocked.
@@ -276,7 +302,7 @@ void munlock_page(struct page *page)
if (!pagevec_add(pvec, page) ||
PageHead(page) || lru_cache_disabled())
mlock_pagevec(pvec);
- put_cpu_var(mlock_pvec);
+ local_unlock(&mlock_pvec.lock);
}
static int mlock_pte_range(pmd_t *pmd, unsigned long addr,
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6c6af8658775..2db95780e003 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8367,6 +8367,7 @@ static int page_alloc_cpu_dead(unsigned int cpu)
struct zone *zone;
lru_add_drain_cpu(cpu);
+ mlock_page_drain_remote(cpu);
drain_pages(cpu);
/*
diff --git a/mm/rmap.c b/mm/rmap.c
index 5cb970d51f0a..fedb82371efe 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1683,7 +1683,7 @@ discard:
*/
page_remove_rmap(subpage, vma, folio_test_hugetlb(folio));
if (vma->vm_flags & VM_LOCKED)
- mlock_page_drain(smp_processor_id());
+ mlock_page_drain_local();
folio_put(folio);
}
@@ -1961,7 +1961,7 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma,
*/
page_remove_rmap(subpage, vma, folio_test_hugetlb(folio));
if (vma->vm_flags & VM_LOCKED)
- mlock_page_drain(smp_processor_id());
+ mlock_page_drain_local();
folio_put(folio);
}
diff --git a/mm/swap.c b/mm/swap.c
index bceff0cb559c..7e320ec08c6a 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -624,7 +624,6 @@ void lru_add_drain_cpu(int cpu)
pagevec_lru_move_fn(pvec, lru_lazyfree_fn);
activate_page_drain(cpu);
- mlock_page_drain(cpu);
}
/**
@@ -706,6 +705,7 @@ void lru_add_drain(void)
local_lock(&lru_pvecs.lock);
lru_add_drain_cpu(smp_processor_id());
local_unlock(&lru_pvecs.lock);
+ mlock_page_drain_local();
}
/*
@@ -720,6 +720,7 @@ static void lru_add_and_bh_lrus_drain(void)
lru_add_drain_cpu(smp_processor_id());
local_unlock(&lru_pvecs.lock);
invalidate_bh_lrus_cpu();
+ mlock_page_drain_local();
}
void lru_add_drain_cpu_zone(struct zone *zone)
@@ -728,6 +729,7 @@ void lru_add_drain_cpu_zone(struct zone *zone)
lru_add_drain_cpu(smp_processor_id());
drain_local_pages(zone);
local_unlock(&lru_pvecs.lock);
+ mlock_page_drain_local();
}
#ifdef CONFIG_SMP