* [PATCH 2/3] kmemleak: Introduce a default off mode for kmemleak
2010-07-15 15:08 [PATCH 0/3] Kmemleak patches for 2.6.36-rc1 Catalin Marinas
2010-07-15 15:09 ` [PATCH 1/3] kmemleak: Show more information for objects found by alias Catalin Marinas
@ 2010-07-15 15:09 ` Catalin Marinas
2010-07-16 9:00 ` Pekka Enberg
2010-07-15 15:09 ` [PATCH 3/3] kmemleak: Add DocBook style comments to kmemleak.c Catalin Marinas
2 siblings, 1 reply; 7+ messages in thread
From: Catalin Marinas @ 2010-07-15 15:09 UTC (permalink / raw)
To: linux-kernel; +Cc: Jason Baron, Pekka Enberg
From: Jason Baron <jbaron@redhat.com>
Introduce a new DEBUG_KMEMLEAK_DEFAULT_OFF config parameter that allows
kmemleak to be disabled by default, but enabled on the command line
via: kmemleak=on. Although a reboot is required to turn it on, its still
useful to not require a re-compile.
Signed-off-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
---
lib/Kconfig.debug | 7 +++++++
mm/kmemleak.c | 14 +++++++++++++-
2 files changed, 20 insertions(+), 1 deletions(-)
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index e722e9d..95ab402 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -400,6 +400,13 @@ config DEBUG_KMEMLEAK_TEST
If unsure, say N.
+config DEBUG_KMEMLEAK_DEFAULT_OFF
+ bool "Default kmemleak to off"
+ depends on DEBUG_KMEMLEAK
+ help
+ Say Y here to disable kmemleak by default. It can then be enabled
+ on the command line via kmemleak=on.
+
config DEBUG_PREEMPT
bool "Debug preemptible kernel"
depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index c2c9feb..d33e990 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -211,6 +211,9 @@ static signed long jiffies_scan_wait;
static int kmemleak_stack_scan = 1;
/* protects the memory scanning, parameters and debug/kmemleak file access */
static DEFINE_MUTEX(scan_mutex);
+/* setting kmemleak=on, will set this var, skipping the disable */
+static int kmemleak_skip_disable;
+
/*
* Early object allocation/freeing logging. Kmemleak is initialized after the
@@ -1604,7 +1607,9 @@ static int kmemleak_boot_config(char *str)
return -EINVAL;
if (strcmp(str, "off") == 0)
kmemleak_disable();
- else if (strcmp(str, "on") != 0)
+ else if (strcmp(str, "on") == 0)
+ kmemleak_skip_disable = 1;
+ else
return -EINVAL;
return 0;
}
@@ -1618,6 +1623,13 @@ void __init kmemleak_init(void)
int i;
unsigned long flags;
+#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
+ if (!kmemleak_skip_disable) {
+ kmemleak_disable();
+ return;
+ }
+#endif
+
jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
^ permalink raw reply [flat|nested] 7+ messages in thread* [PATCH 3/3] kmemleak: Add DocBook style comments to kmemleak.c
2010-07-15 15:08 [PATCH 0/3] Kmemleak patches for 2.6.36-rc1 Catalin Marinas
2010-07-15 15:09 ` [PATCH 1/3] kmemleak: Show more information for objects found by alias Catalin Marinas
2010-07-15 15:09 ` [PATCH 2/3] kmemleak: Introduce a default off mode for kmemleak Catalin Marinas
@ 2010-07-15 15:09 ` Catalin Marinas
2010-07-16 9:02 ` Pekka Enberg
2 siblings, 1 reply; 7+ messages in thread
From: Catalin Marinas @ 2010-07-15 15:09 UTC (permalink / raw)
To: linux-kernel; +Cc: Pekka Enberg
The description and parameters of the kmemleak API weren't obvious. This
patch adds comments clarifying the API usage.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
---
mm/kmemleak.c | 80 ++++++++++++++++++++++++++++++++++++++++++---------------
1 files changed, 59 insertions(+), 21 deletions(-)
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index d33e990..5f2eb5b 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -843,10 +843,19 @@ out:
rcu_read_unlock();
}
-/*
- * Memory allocation function callback. This function is called from the
- * kernel allocators when a new block is allocated (kmem_cache_alloc, kmalloc,
- * vmalloc etc.).
+/**
+ * kmemleak_alloc - register a newly allocated object
+ * @ptr: pointer to beginning of the object
+ * @size: size of the object
+ * @min_count: minimum number of references to this object. If during memory
+ * scanning a number of references less than @min_count is found,
+ * the object is reported as a memory leak. If @min_count is 0,
+ * the object is never reported as a leak. If @min_count is -1,
+ * the object is ignored (not scanned and not reported as a leak)
+ * @gfp: kmalloc() flags used for kmemleak internal memory allocations
+ *
+ * This function is called from the kernel allocators when a new object
+ * (memory block) is allocated (kmem_cache_alloc, kmalloc, vmalloc etc.).
*/
void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
gfp_t gfp)
@@ -860,9 +869,12 @@ void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
}
EXPORT_SYMBOL_GPL(kmemleak_alloc);
-/*
- * Memory freeing function callback. This function is called from the kernel
- * allocators when a block is freed (kmem_cache_free, kfree, vfree etc.).
+/**
+ * kmemleak_free - unregister a previously registered object
+ * @ptr: pointer to beginning of the object
+ *
+ * This function is called from the kernel allocators when an object (memory
+ * block) is freed (kmem_cache_free, kfree, vfree etc.).
*/
void __ref kmemleak_free(const void *ptr)
{
@@ -875,9 +887,14 @@ void __ref kmemleak_free(const void *ptr)
}
EXPORT_SYMBOL_GPL(kmemleak_free);
-/*
- * Partial memory freeing function callback. This function is usually called
- * from bootmem allocator when (part of) a memory block is freed.
+/**
+ * kmemleak_free_part - partially unregister a previously registered object
+ * @ptr: pointer to the beginning or inside the object. This also
+ * represents the start of the range to be freed
+ * @size: size to be unregistered
+ *
+ * This function is called when only a part of a memory block is freed
+ * (usually from the bootmem allocator).
*/
void __ref kmemleak_free_part(const void *ptr, size_t size)
{
@@ -890,9 +907,12 @@ void __ref kmemleak_free_part(const void *ptr, size_t size)
}
EXPORT_SYMBOL_GPL(kmemleak_free_part);
-/*
- * Mark an already allocated memory block as a false positive. This will cause
- * the block to no longer be reported as leak and always be scanned.
+/**
+ * kmemleak_not_leak - mark an allocated object as false positive
+ * @ptr: pointer to beginning of the object
+ *
+ * Calling this function on an object will cause the memory block to no longer
+ * be reported as leak and always be scanned.
*/
void __ref kmemleak_not_leak(const void *ptr)
{
@@ -905,10 +925,14 @@ void __ref kmemleak_not_leak(const void *ptr)
}
EXPORT_SYMBOL(kmemleak_not_leak);
-/*
- * Ignore a memory block. This is usually done when it is known that the
- * corresponding block is not a leak and does not contain any references to
- * other allocated memory blocks.
+/**
+ * kmemleak_ignore - ignore an allocated object
+ * @ptr: pointer to beginning of the object
+ *
+ * Calling this function on an object will cause the memory block to be
+ * ignored (not scanned and not reported as a leak). This is usually done when
+ * it is known that the corresponding block is not a leak and does not contain
+ * any references to other allocated memory blocks.
*/
void __ref kmemleak_ignore(const void *ptr)
{
@@ -921,8 +945,16 @@ void __ref kmemleak_ignore(const void *ptr)
}
EXPORT_SYMBOL(kmemleak_ignore);
-/*
- * Limit the range to be scanned in an allocated memory block.
+/**
+ * kmemleak_scan_area - limit the range to be scanned in an allocated object
+ * @ptr: pointer to beginning or inside the object. This also
+ * represents the start of the scan area
+ * @size: size of the scan area
+ * @gfp: kmalloc() flags used for kmemleak internal memory allocations
+ *
+ * This function is used when it is known that only certain parts of an object
+ * contain references to other objects. Kmemleak will only scan these areas
+ * reducing the number false negatives.
*/
void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
{
@@ -935,8 +967,14 @@ void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
}
EXPORT_SYMBOL(kmemleak_scan_area);
-/*
- * Inform kmemleak not to scan the given memory block.
+/**
+ * kmemleak_no_scan - do not scan an allocated object
+ * @ptr: pointer to beginning of the object
+ *
+ * This function notifies kmemleak not to scan the given memory block. Useful
+ * in situations where it is known that the given object does not contain any
+ * references to other objects. Kmemleak will not scan such objects reducing
+ * the number of false negatives.
*/
void __ref kmemleak_no_scan(const void *ptr)
{
^ permalink raw reply [flat|nested] 7+ messages in thread