The patch titled
Subject: mm/hugetlb: avoid hardcoding while checking if cma is enabled
has been removed from the -mm tree. Its filename was
mm-hugetlb-avoid-hardcoding-while-checking-if-cma-is-enable.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
From: Barry Song <song.bao.hua@xxxxxxxxxxxxx>
Subject: mm/hugetlb: avoid hardcoding while checking if cma is enabled
hugetlb_cma[0] can be NULL due to various reasons, for example, node0 has
no memory. so NULL hugetlb_cma[0] doesn't necessarily mean cma is not
enabled. gigantic pages might have been reserved on other nodes.
Mike Kravetz said:
: Based on the code changes, I believe the following could happen:
: - Someone uses 'hugetlb_cma=' kernel command line parameter to reserve
: CMA for gigantic pages.
: - The system topology is such that no memory is on node 0. Therefore,
: no CMA can be reserved for gigantic pages on node 0. CMA is reserved
: on other nodes.
: - The user also specifies a number of gigantic pages to pre-allocate on
: the command line with hugepagesz=<gigantic_page_size> hugepages=<N>
: - The routine which allocates gigantic pages from the bootmem allocator
: will not detect CMA has been reserved as there is no memory on node 0.
: Therefore, pages will be pre-allocated from bootmem allocator as well
: as reserved in CMA.
:
: This double allocation (bootmem and CMA) is the worst case scenario. Not
: sure if this is what Barry saw, and I suspect this would rarely happen.
Link: http://lkml.kernel.org/r/20200707040204.30132-1-song.bao.hua@xxxxxxxxxxxxx
Fixes: cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Signed-off-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx>
Acked-by: Roman Gushchin <guro@xxxxxx>
Acked-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Jonathan Cameron <jonathan.cameron@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
--- a/mm/hugetlb.c~mm-hugetlb-avoid-hardcoding-while-checking-if-cma-is-enable
+++ a/mm/hugetlb.c
@@ -2546,6 +2546,20 @@ static void __init gather_bootmem_preall
}
}
+bool __init hugetlb_cma_enabled(void)
+{
+#ifdef CONFIG_CMA
+ int node;
+
+ for_each_online_node(node) {
+ if (hugetlb_cma[node])
+ return true;
+ }
+#endif
+
+ return false;
+}
+
static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
{
unsigned long i;
@@ -2571,7 +2585,7 @@ static void __init hugetlb_hstate_alloc_
for (i = 0; i < h->max_huge_pages; ++i) {
if (hstate_is_gigantic(h)) {
- if (IS_ENABLED(CONFIG_CMA) && hugetlb_cma[0]) {
+ if (hugetlb_cma_enabled()) {
pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
break;
}
_
Patches currently in -mm which might be from song.bao.hua@xxxxxxxxxxxxx are
mm-hugetlb-split-hugetlb_cma-in-nodes-with-memory.patch
mm-cma-fix-the-name-of-cma-areas.patch
mm-hugetlb-fix-the-name-of-hugetlb-cma.patch
mm-hugetlb-avoid-hardcoding-while-checking-if-cma-is-enabled.patch
