Thread (10 messages) 10 messages, 2 authors, 2021-10-11

Re: [PATCH v1] mm: page_alloc: Add debug log in free_reserved_area for static memory

From: David Hildenbrand <hidden>
Date: 2021-09-28 10:39:25
Also in: lkml

On 28.09.21 11:04, Faiyaz Mohammed wrote:
quoted hunk ↗ jump to hunk
For INITRD and initmem memory is reserved through "memblock_reserve"
during boot up but it is free via "free_reserved_area" instead
of "memblock_free".
For example:
[    0.294848] Freeing initrd memory: 12K.
[    0.696688] Freeing unused kernel memory: 4096K.

To get the start and end address of the above freed memory and to account
proper memblock added memblock_dbg log in "free_reserved_area".
After adding log:
[    0.294837] memblock_free: [0x00000083600000-0x00000083603000] free_initrd_mem+0x20/0x28
[    0.294848] Freeing initrd memory: 12K.
[    0.695246] memblock_free: [0x00000081600000-0x00000081a00000] free_initmem+0x70/0xc8
[    0.696688] Freeing unused kernel memory: 4096K.

Signed-off-by: Faiyaz Mohammed <redacted>
---
  mm/page_alloc.c | 5 +++++
  1 file changed, 5 insertions(+)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b37435c..f85c3b2 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8129,6 +8129,11 @@ unsigned long free_reserved_area(void *start, void *end, int poison, const char
  		pr_info("Freeing %s memory: %ldK\n",
  			s, pages << (PAGE_SHIFT - 10));
  
+#ifdef CONFIG_HAVE_MEMBLOCK
+		memblock_dbg("memblock_free: [%#016llx-%#016llx] %pS\n",
+			__pa(start), __pa(end), (void *)_RET_IP_);
+#endif
IMHO, the "memblock_free" part is misleading. Something was allocated 
early via memblock, then we transitioned to the buddy, now we're freeing 
that early allocation via the buddy.

I would not expect memblock_dbg once memblock might not actually be 
alive anymore.

-- 
Thanks,

David / dhildenb

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