On 29.09.21 10:58, Faiyaz Mohammed wrote:

On 9/28/2021 4:46 PM, David Hildenbrand wrote:

quoted

On 28.09.21 12:53, Faiyaz Mohammed wrote:

quoted

On 9/28/2021 4:09 PM, David Hildenbrand wrote:

quoted

On 28.09.21 11:04, Faiyaz Mohammed wrote:

quoted

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.
Yes, we're freeing the early allocation via buddy, but for proper

memblock accounting we need this debug print.

What do you mean with "accounting" ? These are debug statements.

Yes, these are debug statements, which help to know the a-b address
belongs to x callsite. This info is required when memblock=debug is
passed through command line and CONFIG_HAVE_MEMBLOCK is enabled.

The issue I'm having is talking in the name of memblock "memblock_dbg, 
memblock_free", when memblock might no longer be around. We have other 
places where we free early memblock allocations back to the buddy.

-- 
Thanks,

David / dhildenb