The quilt patch titled
Subject: mm/hugetlb: pass correct order_per_bit to cma_declare_contiguous_nid
has been removed from the -mm tree. Its filename was
mm-hugetlb-pass-correct-order_per_bit-to-cma_declare_contiguous_nid.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Frank van der Linden <fvdl@xxxxxxxxxx>
Subject: mm/hugetlb: pass correct order_per_bit to cma_declare_contiguous_nid
Date: Thu, 4 Apr 2024 16:25:15 +0000
The hugetlb_cma code passes 0 in the order_per_bit argument to
cma_declare_contiguous_nid (the alignment, computed using the page order,
is correctly passed in).
This causes a bit in the cma allocation bitmap to always represent a 4k
page, making the bitmaps potentially very large, and slower.
It would create bitmaps that would be pretty big. E.g. for a 4k page
size on x86, hugetlb_cma=64G would mean a bitmap size of (64G / 4k) / 8
== 2M. With HUGETLB_PAGE_ORDER as order_per_bit, as intended, this
would be (64G / 2M) / 8 == 4k. So, that's quite a difference.
Also, this restricted the hugetlb_cma area to ((PAGE_SIZE <<
MAX_PAGE_ORDER) * 8) * PAGE_SIZE (e.g. 128G on x86) , since
bitmap_alloc uses normal page allocation, and is thus restricted by
MAX_PAGE_ORDER. Specifying anything about that would fail the CMA
initialization.
So, correctly pass in the order instead.
Link: https://lkml.kernel.org/r/20240404162515.527802-2-fvdl@xxxxxxxxxx
Fixes: cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Signed-off-by: Frank van der Linden <fvdl@xxxxxxxxxx>
Acked-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/mm/hugetlb.c~mm-hugetlb-pass-correct-order_per_bit-to-cma_declare_contiguous_nid
+++ a/mm/hugetlb.c
@@ -7794,9 +7794,9 @@ void __init hugetlb_cma_reserve(int orde
* huge page demotion.
*/
res = cma_declare_contiguous_nid(0, size, 0,
- PAGE_SIZE << HUGETLB_PAGE_ORDER,
- 0, false, name,
- &hugetlb_cma[nid], nid);
+ PAGE_SIZE << HUGETLB_PAGE_ORDER,
+ HUGETLB_PAGE_ORDER, false, name,
+ &hugetlb_cma[nid], nid);
if (res) {
pr_warn("hugetlb_cma: reservation failed: err %d, node %d",
res, nid);
_
Patches currently in -mm which might be from fvdl@xxxxxxxxxx are
