The patch titled
Subject: mm-kmemleak-optimise-kmemleak_lock-acquiring-during-kmemleak_scan-v2
has been added to the -mm tree. Its filename is
mm-kmemleak-optimise-kmemleak_lock-acquiring-during-kmemleak_scan-v2.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-kmemleak-optimise-kmemleak_lock-acquiring-during-kmemleak_scan-v2.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-kmemleak-optimise-kmemleak_lock-acquiring-during-kmemleak_scan-v2.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Catalin Marinas <catalin.marinas@xxxxxxx>
Subject: mm-kmemleak-optimise-kmemleak_lock-acquiring-during-kmemleak_scan-v2
- scan_block() allow_resched logic moved outside the function since the
interrupts inside kmemleak_lock region are disabled.
- introduced a scan_large_block() function to split large memory blocks
in MAX_SCAN_SIZE chunks
- redundant object->flags & OBJECT_NO_SCAN check removed
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/kmemleak.c | 66 ++++++++++++++++++++++++++----------------------
1 file changed, 37 insertions(+), 29 deletions(-)
diff -puN mm/kmemleak.c~mm-kmemleak-optimise-kmemleak_lock-acquiring-during-kmemleak_scan-v2 mm/kmemleak.c
--- a/mm/kmemleak.c~mm-kmemleak-optimise-kmemleak_lock-acquiring-during-kmemleak_scan-v2
+++ a/mm/kmemleak.c
@@ -1171,24 +1171,18 @@ static int scan_should_stop(void)
* found to the gray list.
*/
static void scan_block(void *_start, void *_end,
- struct kmemleak_object *scanned, int allow_resched)
+ struct kmemleak_object *scanned)
{
unsigned long *ptr;
unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
unsigned long *end = _end - (BYTES_PER_POINTER - 1);
- unsigned long klflags;
+ unsigned long flags;
- read_lock_irqsave(&kmemleak_lock, klflags);
+ read_lock_irqsave(&kmemleak_lock, flags);
for (ptr = start; ptr < end; ptr++) {
struct kmemleak_object *object;
- unsigned long flags;
unsigned long pointer;
- if (allow_resched && need_resched()) {
- read_unlock_irqrestore(&kmemleak_lock, klflags);
- cond_resched();
- read_lock_irqsave(&kmemleak_lock, klflags);
- }
if (scan_should_stop())
break;
@@ -1222,11 +1216,10 @@ static void scan_block(void *_start, voi
* previously acquired in scan_object(). These locks are
* enclosed by scan_mutex.
*/
- spin_lock_irqsave_nested(&object->lock, flags,
- SINGLE_DEPTH_NESTING);
+ spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
if (!color_white(object)) {
/* non-orphan, ignored or new */
- spin_unlock_irqrestore(&object->lock, flags);
+ spin_unlock(&object->lock);
continue;
}
@@ -1241,13 +1234,25 @@ static void scan_block(void *_start, voi
/* put_object() called when removing from gray_list */
WARN_ON(!get_object(object));
list_add_tail(&object->gray_list, &gray_list);
- spin_unlock_irqrestore(&object->lock, flags);
- continue;
}
+ spin_unlock(&object->lock);
+ }
+ read_unlock_irqrestore(&kmemleak_lock, flags);
+}
- spin_unlock_irqrestore(&object->lock, flags);
+/*
+ * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency.
+ */
+static void scan_large_block(void *start, void *end)
+{
+ void *next;
+
+ while (start < end) {
+ next = min(start + MAX_SCAN_SIZE, end);
+ scan_block(start, next, NULL);
+ start = next;
+ cond_resched();
}
- read_unlock_irqrestore(&kmemleak_lock, klflags);
}
/*
@@ -1272,22 +1277,25 @@ static void scan_object(struct kmemleak_
if (hlist_empty(&object->area_list)) {
void *start = (void *)object->pointer;
void *end = (void *)(object->pointer + object->size);
+ void *next;
- while (start < end && (object->flags & OBJECT_ALLOCATED) &&
- !(object->flags & OBJECT_NO_SCAN)) {
- scan_block(start, min(start + MAX_SCAN_SIZE, end),
- object, 0);
- start += MAX_SCAN_SIZE;
+ do {
+ next = min(start + MAX_SCAN_SIZE, end);
+ scan_block(start, next, object);
+
+ start = next;
+ if (start >= end)
+ break;
spin_unlock_irqrestore(&object->lock, flags);
cond_resched();
spin_lock_irqsave(&object->lock, flags);
- }
+ } while (object->flags & OBJECT_ALLOCATED);
} else
hlist_for_each_entry(area, &object->area_list, node)
scan_block((void *)area->start,
(void *)(area->start + area->size),
- object, 0);
+ object);
out:
spin_unlock_irqrestore(&object->lock, flags);
}
@@ -1364,14 +1372,14 @@ static void kmemleak_scan(void)
rcu_read_unlock();
/* data/bss scanning */
- scan_block(_sdata, _edata, NULL, 1);
- scan_block(__bss_start, __bss_stop, NULL, 1);
+ scan_large_block(_sdata, _edata);
+ scan_large_block(__bss_start, __bss_stop);
#ifdef CONFIG_SMP
/* per-cpu sections scanning */
for_each_possible_cpu(i)
- scan_block(__per_cpu_start + per_cpu_offset(i),
- __per_cpu_end + per_cpu_offset(i), NULL, 1);
+ scan_large_block(__per_cpu_start + per_cpu_offset(i),
+ __per_cpu_end + per_cpu_offset(i));
#endif
/*
@@ -1392,7 +1400,7 @@ static void kmemleak_scan(void)
/* only scan if page is in use */
if (page_count(page) == 0)
continue;
- scan_block(page, page + 1, NULL, 1);
+ scan_block(page, page + 1, NULL);
}
}
put_online_mems();
@@ -1406,7 +1414,7 @@ static void kmemleak_scan(void)
read_lock(&tasklist_lock);
do_each_thread(g, p) {
scan_block(task_stack_page(p), task_stack_page(p) +
- THREAD_SIZE, NULL, 0);
+ THREAD_SIZE, NULL);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
}
_
Patches currently in -mm which might be from catalin.marinas@xxxxxxx are
mm-hugetlb-reduce-arch-dependent-code-about-huge_pmd_unshare.patch
mm-kmemleak-allow-safe-memory-scanning-during-kmemleak-disabling.patch
mm-kmemleak-fix-delete_object_-race-when-called-on-the-same-memory-block.patch
mm-kmemleak-do-not-acquire-scan_mutex-in-kmemleak_do_cleanup.patch
mm-kmemleak-avoid-deadlock-on-the-kmemleak-object-insertion-error-path.patch
mm-kmemleak-optimise-kmemleak_lock-acquiring-during-kmemleak_scan.patch
mm-kmemleak-optimise-kmemleak_lock-acquiring-during-kmemleak_scan-v2.patch
linux-next.patch
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