Originally, hugetlb_cgroup was the only hugetlb user of tail page
structure fields. So, the code defined and checked against
HUGETLB_CGROUP_MIN_ORDER to make sure pages weren't too small
to use.
However, by now, tail page #2 is used to store hugetlb
hwpoison and subpool information as well. In other words,
without that tail page hugetlb doesn't work.
Acknowledge this fact by getting rid of HUGETLB_CGROUP_MIN_ORDER
and checks against it. Instead, just check for the minimum viable
page order at hstate creation time.
Signed-off-by: Frank van der Linden <fvdl@xxxxxxxxxx>
---
include/linux/hugetlb_cgroup.h | 11 -----------
mm/hugetlb.c | 2 +-
mm/hugetlb_cgroup.c | 20 ++------------------
3 files changed, 3 insertions(+), 30 deletions(-)
diff --git a/include/linux/hugetlb_cgroup.h b/include/linux/hugetlb_cgroup.h
index 3d82d91f49ac..e5d64b8b59c2 100644
--- a/include/linux/hugetlb_cgroup.h
+++ b/include/linux/hugetlb_cgroup.h
@@ -22,13 +22,6 @@ struct resv_map;
struct file_region;
#ifdef CONFIG_CGROUP_HUGETLB
-/*
- * Minimum page order trackable by hugetlb cgroup.
- * At least 3 pages are necessary for all the tracking information.
- * The second tail page contains all of the hugetlb-specific fields.
- */
-#define HUGETLB_CGROUP_MIN_ORDER order_base_2(__NR_USED_SUBPAGE)
-
enum hugetlb_memory_event {
HUGETLB_MAX,
HUGETLB_NR_MEMORY_EVENTS,
@@ -68,8 +61,6 @@ static inline struct hugetlb_cgroup *
__hugetlb_cgroup_from_folio(struct folio *folio, bool rsvd)
{
VM_BUG_ON_FOLIO(!folio_test_hugetlb(folio), folio);
- if (folio_order(folio) < HUGETLB_CGROUP_MIN_ORDER)
- return NULL;
if (rsvd)
return folio->_hugetlb_cgroup_rsvd;
else
@@ -91,8 +82,6 @@ static inline void __set_hugetlb_cgroup(struct folio *folio,
struct hugetlb_cgroup *h_cg, bool rsvd)
{
VM_BUG_ON_FOLIO(!folio_test_hugetlb(folio), folio);
- if (folio_order(folio) < HUGETLB_CGROUP_MIN_ORDER)
- return;
if (rsvd)
folio->_hugetlb_cgroup_rsvd = h_cg;
else
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 52d26072dfda..7c3e479abb68 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4282,7 +4282,7 @@ void __init hugetlb_add_hstate(unsigned int order)
return;
}
BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
- BUG_ON(order == 0);
+ BUG_ON(order < order_base_2(__NR_USED_SUBPAGE));
h = &hstates[hugetlb_max_hstate++];
mutex_init(&h->resize_lock);
h->order = order;
diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index dedd2edb076e..aa4486bd3904 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -262,12 +262,6 @@ static int __hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
if (hugetlb_cgroup_disabled())
goto done;
- /*
- * We don't charge any cgroup if the compound page have less
- * than 3 pages.
- */
- if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
- goto done;
again:
rcu_read_lock();
h_cg = hugetlb_cgroup_from_task(current);
@@ -397,9 +391,6 @@ static void __hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
if (hugetlb_cgroup_disabled() || !h_cg)
return;
- if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
- return;
-
page_counter_uncharge(__hugetlb_cgroup_counter_from_cgroup(h_cg, idx,
rsvd),
nr_pages);
@@ -869,15 +860,8 @@ void __init hugetlb_cgroup_file_init(void)
{
struct hstate *h;
- for_each_hstate(h) {
- /*
- * Add cgroup control files only if the huge page consists
- * of more than two normal pages. This is because we use
- * page[2].private for storing cgroup details.
- */
- if (huge_page_order(h) >= HUGETLB_CGROUP_MIN_ORDER)
- __hugetlb_cgroup_file_init(hstate_index(h));
- }
+ for_each_hstate(h)
+ __hugetlb_cgroup_file_init(hstate_index(h));
}
/*
--
2.42.0.582.g8ccd20d70d-goog
