Re: [PATCH] hugetlb: document the new location of page subpool pointer

From: David Hildenbrand
Date: Wed Feb 24 2021 - 05:09:06 EST


On 24.02.21 05:04, Mike Kravetz wrote:
Expand comments, no functional change.

Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
---
include/linux/hugetlb.h | 3 +++
1 file changed, 3 insertions(+)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index cccd1aab69dd..c0467a7a1fe0 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -476,6 +476,9 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
* huegtlb page specific state flags. These flags are located in page.private
* of the hugetlb head page. Functions created via the below macros should be
* used to manipulate these flags.
+ * Note: The hugetlb page subpool pointer previously located at page.private
+ * was moved to page[1].private to make room for flags in the head page. See
+ * hugetlb_page_subpool().
*
* HPG_restore_reserve - Set when a hugetlb page consumes a reservation at
* allocation time. Cleared when page is fully instantiated. Free


Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>

--
Thanks,

David / dhildenb