The patch titled
Subject: mm, slub: optionally save/restore irqs in slab_[un]lock()/
has been added to the -mm tree. Its filename is
mm-slub-optionally-save-restore-irqs-in-slab_lock.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-slub-optionally-save-restore-irqs-in-slab_lock.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-slub-optionally-save-restore-irqs-in-slab_lock.patch
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------------------------------------------------------
From: Vlastimil Babka <vbabka@xxxxxxx>
Subject: mm, slub: optionally save/restore irqs in slab_[un]lock()/
For PREEMPT_RT we will need to disable irqs for this bit spinlock. As a
preparation, add a flags parameter, and an internal version that takes
additional bool parameter to control irq saving/restoring (the flags
parameter is compile-time unused if the bool is a constant false).
Convert ___cmpxchg_double_slab(), which also comes with the same bool
parameter, to use the internal version.
Link: https://lkml.kernel.org/r/20210805152000.12817-32-vbabka@xxxxxxx
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slub.c | 52 +++++++++++++++++++++++++++++++++-------------------
1 file changed, 33 insertions(+), 19 deletions(-)
--- a/mm/slub.c~mm-slub-optionally-save-restore-irqs-in-slab_lock
+++ a/mm/slub.c
@@ -359,16 +359,33 @@ static inline unsigned int oo_objects(st
/*
* Per slab locking using the pagelock
*/
-static __always_inline void slab_lock(struct page *page)
+static __always_inline void
+__slab_lock(struct page *page, unsigned long *flags, bool disable_irqs)
{
VM_BUG_ON_PAGE(PageTail(page), page);
+ if (disable_irqs)
+ local_irq_save(*flags);
bit_spin_lock(PG_locked, &page->flags);
}
-static __always_inline void slab_unlock(struct page *page)
+static __always_inline void
+__slab_unlock(struct page *page, unsigned long *flags, bool disable_irqs)
{
VM_BUG_ON_PAGE(PageTail(page), page);
__bit_spin_unlock(PG_locked, &page->flags);
+ if (disable_irqs)
+ local_irq_restore(*flags);
+}
+
+static __always_inline void
+slab_lock(struct page *page, unsigned long *flags)
+{
+ __slab_lock(page, flags, false);
+}
+
+static __always_inline void slab_unlock(struct page *page, unsigned long *flags)
+{
+ __slab_unlock(page, flags, false);
}
static inline bool ___cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
@@ -388,23 +405,18 @@ static inline bool ___cmpxchg_double_sla
} else
#endif
{
- unsigned long flags;
+ /* init to 0 to prevent spurious warnings */
+ unsigned long flags = 0;
- if (disable_irqs)
- local_irq_save(flags);
- slab_lock(page);
+ __slab_lock(page, &flags, disable_irqs);
if (page->freelist == freelist_old &&
page->counters == counters_old) {
page->freelist = freelist_new;
page->counters = counters_new;
- slab_unlock(page);
- if (disable_irqs)
- local_irq_restore(flags);
+ __slab_unlock(page, &flags, disable_irqs);
return true;
}
- slab_unlock(page);
- if (disable_irqs)
- local_irq_restore(flags);
+ __slab_unlock(page, &flags, disable_irqs);
}
cpu_relax();
@@ -1255,11 +1267,11 @@ static noinline int free_debug_processin
struct kmem_cache_node *n = get_node(s, page_to_nid(page));
void *object = head;
int cnt = 0;
- unsigned long flags;
+ unsigned long flags, flags2;
int ret = 0;
spin_lock_irqsave(&n->list_lock, flags);
- slab_lock(page);
+ slab_lock(page, &flags2);
if (s->flags & SLAB_CONSISTENCY_CHECKS) {
if (!check_slab(s, page))
@@ -1292,7 +1304,7 @@ out:
slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n",
bulk_cnt, cnt);
- slab_unlock(page);
+ slab_unlock(page, &flags2);
spin_unlock_irqrestore(&n->list_lock, flags);
if (!ret)
slab_fix(s, "Object at 0x%p not freed", object);
@@ -4051,9 +4063,10 @@ static void list_slab_objects(struct kme
void *addr = page_address(page);
unsigned long *map;
void *p;
+ unsigned long flags;
slab_err(s, page, text, s->name);
- slab_lock(page);
+ slab_lock(page, &flags);
map = get_map(s, page);
for_each_object(p, s, addr, page->objects) {
@@ -4064,7 +4077,7 @@ static void list_slab_objects(struct kme
}
}
put_map(map);
- slab_unlock(page);
+ slab_unlock(page, &flags);
#endif
}
@@ -4789,8 +4802,9 @@ static void validate_slab(struct kmem_ca
{
void *p;
void *addr = page_address(page);
+ unsigned long flags;
- slab_lock(page);
+ slab_lock(page, &flags);
if (!check_slab(s, page) || !on_freelist(s, page, NULL))
goto unlock;
@@ -4805,7 +4819,7 @@ static void validate_slab(struct kmem_ca
break;
}
unlock:
- slab_unlock(page);
+ slab_unlock(page, &flags);
}
static int validate_slab_node(struct kmem_cache *s,
_
Patches currently in -mm which might be from vbabka@xxxxxxx are
mm-slub-fix-slub_debug-disablement-for-list-of-slabs.patch
mm-slub-dont-call-flush_all-from-slab_debug_trace_open.patch
mm-slub-allocate-private-object-map-for-debugfs-listings.patch
mm-slub-allocate-private-object-map-for-validate_slab_cache.patch
mm-slub-dont-disable-irq-for-debug_check_no_locks_freed.patch
mm-slub-remove-redundant-unfreeze_partials-from-put_cpu_partial.patch
mm-slub-unify-cmpxchg_double_slab-and-__cmpxchg_double_slab.patch
mm-slub-extract-get_partial-from-new_slab_objects.patch
mm-slub-dissolve-new_slab_objects-into-___slab_alloc.patch
mm-slub-return-slab-page-from-get_partial-and-set-c-page-afterwards.patch
mm-slub-restructure-new-page-checks-in-___slab_alloc.patch
mm-slub-simplify-kmem_cache_cpu-and-tid-setup.patch
mm-slub-move-disabling-enabling-irqs-to-___slab_alloc.patch
mm-slub-do-initial-checks-in-___slab_alloc-with-irqs-enabled.patch
mm-slub-move-disabling-irqs-closer-to-get_partial-in-___slab_alloc.patch
mm-slub-restore-irqs-around-calling-new_slab.patch
mm-slub-validate-slab-from-partial-list-or-page-allocator-before-making-it-cpu-slab.patch
mm-slub-check-new-pages-with-restored-irqs.patch
mm-slub-stop-disabling-irqs-around-get_partial.patch
mm-slub-move-reset-of-c-page-and-freelist-out-of-deactivate_slab.patch
mm-slub-make-locking-in-deactivate_slab-irq-safe.patch
mm-slub-call-deactivate_slab-without-disabling-irqs.patch
mm-slub-move-irq-control-into-unfreeze_partials.patch
mm-slub-discard-slabs-in-unfreeze_partials-without-irqs-disabled.patch
mm-slub-detach-whole-partial-list-at-once-in-unfreeze_partials.patch
mm-slub-separate-detaching-of-partial-list-in-unfreeze_partials-from-unfreezing.patch
mm-slub-only-disable-irq-with-spin_lock-in-__unfreeze_partials.patch
mm-slub-dont-disable-irqs-in-slub_cpu_dead.patch
mm-slab-make-flush_slab-possible-to-call-with-irqs-enabled.patch
mm-slub-optionally-save-restore-irqs-in-slab_lock.patch
mm-slub-make-slab_lock-disable-irqs-with-preempt_rt.patch
mm-slub-protect-put_cpu_partial-with-disabled-irqs-instead-of-cmpxchg.patch
mm-slub-use-migrate_disable-on-preempt_rt.patch
mm-slub-convert-kmem_cpu_slab-protection-to-local_lock.patch
