Re: [PATCH v4 2/9] hugetlb_cgroup: add interface for charge/uncharge hugetlb reservations

From: shuah
Date: Mon Sep 16 2019 - 21:29:39 EST

On 9/10/19 5:31 PM, Mina Almasry wrote:
Augements hugetlb_cgroup_charge_cgroup to be able to charge hugetlb
usage or hugetlb reservation counter.


Augments?

Adds a new interface to uncharge a hugetlb_cgroup counter via
hugetlb_cgroup_uncharge_counter.

Integrates the counter with hugetlb_cgroup, via hugetlb_cgroup_init,
hugetlb_cgroup_have_usage, and hugetlb_cgroup_css_offline.

Signed-off-by: Mina Almasry <almasrymina@xxxxxxxxxx>
---
include/linux/hugetlb_cgroup.h | 13 ++++--
mm/hugetlb.c | 6 ++-
mm/hugetlb_cgroup.c | 82 +++++++++++++++++++++++++++-------
3 files changed, 80 insertions(+), 21 deletions(-)

diff --git a/include/linux/hugetlb_cgroup.h b/include/linux/hugetlb_cgroup.h
index 063962f6dfc6a..c467715dd8fb8 100644
--- a/include/linux/hugetlb_cgroup.h
+++ b/include/linux/hugetlb_cgroup.h
@@ -52,14 +52,19 @@ static inline bool hugetlb_cgroup_disabled(void)
}

extern int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
- struct hugetlb_cgroup **ptr);
+ struct hugetlb_cgroup **ptr,
+ bool reserved);
extern void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
struct hugetlb_cgroup *h_cg,
struct page *page);
extern void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages,
struct page *page);
extern void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
- struct hugetlb_cgroup *h_cg);
+ struct hugetlb_cgroup *h_cg,
+ bool reserved);
+extern void hugetlb_cgroup_uncharge_counter(struct page_counter *p,
+ unsigned long nr_pages);
+
extern void hugetlb_cgroup_file_init(void) __init;
extern void hugetlb_cgroup_migrate(struct page *oldhpage,
struct page *newhpage);
@@ -83,7 +88,7 @@ static inline bool hugetlb_cgroup_disabled(void)

static inline int
hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
- struct hugetlb_cgroup **ptr)
+ struct hugetlb_cgroup **ptr, bool reserved)
Please line the arguments.

{
return 0;
}
@@ -102,7 +107,7 @@ hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages, struct page *page)

static inline void
hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
- struct hugetlb_cgroup *h_cg)
+ struct hugetlb_cgroup *h_cg, bool reserved)

Same here.

{
}

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 6d7296dd11b83..e975f55aede94 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2078,7 +2078,8 @@ struct page *alloc_huge_page(struct vm_area_struct *vma,
gbl_chg = 1;
}

- ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
+ ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg,
+ false);
if (ret)
goto out_subpool_put;

@@ -2126,7 +2127,8 @@ struct page *alloc_huge_page(struct vm_area_struct *vma,
return page;

out_uncharge_cgroup:
- hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
+ hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg,
+ false);

Please be consistent with indentation. Line this up like you did above.

out_subpool_put:
if (map_chg || avoid_reserve)
hugepage_subpool_put_pages(spool, 1);
diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index 51a72624bd1ff..2ab36a98d834e 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -38,8 +38,8 @@ struct hugetlb_cgroup {
static struct hugetlb_cgroup *root_h_cgroup __read_mostly;

static inline
-struct page_counter *hugetlb_cgroup_get_counter(struct hugetlb_cgroup *h_cg, int idx,
- bool reserved)
+struct page_counter *hugetlb_cgroup_get_counter(struct hugetlb_cgroup *h_cg,
+ int idx, bool reserved)

Same here.

{
if (reserved)
return &h_cg->reserved_hugepage[idx];
@@ -74,8 +74,12 @@ static inline bool hugetlb_cgroup_have_usage(struct hugetlb_cgroup *h_cg)
int idx;

for (idx = 0; idx < hugetlb_max_hstate; idx++) {
- if (page_counter_read(&h_cg->hugepage[idx]))
+ if (page_counter_read(hugetlb_cgroup_get_counter(h_cg, idx,
+ true)) ||
+ page_counter_read(hugetlb_cgroup_get_counter(h_cg, idx,
+ false))) {
return true;
+ }
}
return false;
}
@@ -86,18 +90,30 @@ static void hugetlb_cgroup_init(struct hugetlb_cgroup *h_cgroup,
int idx;

for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) {
- struct page_counter *counter = &h_cgroup->hugepage[idx];
struct page_counter *parent = NULL;
+ struct page_counter *reserved_parent = NULL;
unsigned long limit;
int ret;

- if (parent_h_cgroup)
- parent = &parent_h_cgroup->hugepage[idx];
- page_counter_init(counter, parent);
+ if (parent_h_cgroup) {
+ parent = hugetlb_cgroup_get_counter(
+ parent_h_cgroup, idx, false);
+ reserved_parent = hugetlb_cgroup_get_counter(
+ parent_h_cgroup, idx, true);
+ }
+ page_counter_init(hugetlb_cgroup_get_counter(
+ h_cgroup, idx, false), parent);
+ page_counter_init(hugetlb_cgroup_get_counter(
+ h_cgroup, idx, true),
+ reserved_parent);

limit = round_down(PAGE_COUNTER_MAX,
1 << huge_page_order(&hstates[idx]));
- ret = page_counter_set_max(counter, limit);
+
+ ret = page_counter_set_max(hugetlb_cgroup_get_counter(
+ h_cgroup, idx, false), limit);
+ ret = page_counter_set_max(hugetlb_cgroup_get_counter(
+ h_cgroup, idx, true), limit);
VM_BUG_ON(ret);
}
}
@@ -127,6 +143,26 @@ static void hugetlb_cgroup_css_free(struct cgroup_subsys_state *css)
kfree(h_cgroup);
}

+static void hugetlb_cgroup_move_parent_reservation(int idx,
+ struct hugetlb_cgroup *h_cg)
+{
+ struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(h_cg);
+
+ /* Move the reservation counters. */
+ if (!parent_hugetlb_cgroup(h_cg)) {
+ parent = root_h_cgroup;
+ /* root has no limit */
+ page_counter_charge(
+ &root_h_cgroup->reserved_hugepage[idx],
+ page_counter_read(hugetlb_cgroup_get_counter(
+ h_cg, idx, true)));
+ }
+
+ /* Take the pages off the local counter */
+ page_counter_cancel(hugetlb_cgroup_get_counter(h_cg, idx, true),
+ page_counter_read(hugetlb_cgroup_get_counter(h_cg,
+ idx, true)));
+}

/*
* Should be called with hugetlb_lock held.
@@ -181,6 +217,7 @@ static void hugetlb_cgroup_css_offline(struct cgroup_subsys_state *css)
do {
for_each_hstate(h) {
spin_lock(&hugetlb_lock);
+ hugetlb_cgroup_move_parent_reservation(idx, h_cg);
list_for_each_entry(page, &h->hugepage_activelist, lru)
hugetlb_cgroup_move_parent(idx, h_cg, page);

@@ -192,7 +229,7 @@ static void hugetlb_cgroup_css_offline(struct cgroup_subsys_state *css)
}

int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
- struct hugetlb_cgroup **ptr)
+ struct hugetlb_cgroup **ptr, bool reserved)
{
int ret = 0;
struct page_counter *counter;
@@ -215,8 +252,11 @@ int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
}
rcu_read_unlock();

- if (!page_counter_try_charge(&h_cg->hugepage[idx], nr_pages, &counter))
+ if (!page_counter_try_charge(hugetlb_cgroup_get_counter(h_cg, idx,
+ reserved),
+ nr_pages, &counter)) {
ret = -ENOMEM;
+ }
css_put(&h_cg->css);
done:
*ptr = h_cg;
@@ -250,12 +290,14 @@ void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages,
if (unlikely(!h_cg))
return;
set_hugetlb_cgroup(page, NULL);
- page_counter_uncharge(&h_cg->hugepage[idx], nr_pages);
+ page_counter_uncharge(hugetlb_cgroup_get_counter(h_cg, idx, false),
+ nr_pages);
+
return;
}

void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
- struct hugetlb_cgroup *h_cg)
+ struct hugetlb_cgroup *h_cg, bool reserved)
{
if (hugetlb_cgroup_disabled() || !h_cg)
return;
@@ -263,8 +305,17 @@ void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
return;

- page_counter_uncharge(&h_cg->hugepage[idx], nr_pages);
- return;
+ page_counter_uncharge(hugetlb_cgroup_get_counter(h_cg, idx, reserved),
+ nr_pages);
+}
+
+void hugetlb_cgroup_uncharge_counter(struct page_counter *p,
+ unsigned long nr_pages)
+{
+ if (hugetlb_cgroup_disabled() || !p)
+ return;
+
+ page_counter_uncharge(p, nr_pages);
}

static u64 hugetlb_cgroup_read_u64(struct cgroup_subsys_state *css,
@@ -326,7 +377,8 @@ static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of,
/* Fall through. */
case HUGETLB_RES_LIMIT:
mutex_lock(&hugetlb_limit_mutex);
- ret = page_counter_set_max(hugetlb_cgroup_get_counter(h_cg, idx, reserved),
+ ret = page_counter_set_max(hugetlb_cgroup_get_counter(h_cg, idx,
+ reserved),
nr_pages);
mutex_unlock(&hugetlb_limit_mutex);
break;
--
2.23.0.162.g0b9fbb3734-goog


thanks,
-- Shuah