[PATCH 1/2] mm/memblock: add more comments in code

From: Grygorii Strashko
Date: Wed Dec 11 2013 - 09:39:16 EST


Add additional description on:
- why warning is produced in case if slab is ready
- why kmemleak_alloc is called for each allocated memory block

Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
---

It's additional change on top of the memblock series
https://lkml.org/lkml/2013/12/9/715

mm/memblock.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/mm/memblock.c b/mm/memblock.c
index d03d50a..974f0d3 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -985,6 +985,11 @@ static void * __init memblock_virt_alloc_internal(
pr_warn("%s: usage of MAX_NUMNODES is depricated. Use NUMA_NO_NODE\n",
__func__);

+ /*
+ * Detect any accidental use of these APIs after slab is ready, as at
+ * this moment memblock may be deinitialized already and its
+ * internal data may be destroyed (after execution of free_all_bootmem)
+ */
if (WARN_ON_ONCE(slab_is_available()))
return kzalloc_node(size, GFP_NOWAIT, nid);

@@ -1021,7 +1026,9 @@ done:

/*
* The min_count is set to 0 so that bootmem allocated blocks
- * are never reported as leaks.
+ * are never reported as leaks. This is because many of these blocks
+ * are only referred via the physical address which is not
+ * looked up by kmemleak.
*/
kmemleak_alloc(ptr, size, 0, 0);

--
1.7.9.5

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