[PATCH mm v2] memcg: enable memory accounting in __alloc_pages_bulk

Vasily Averin
2021-10-12T10:18:39Z

Enable memory accounting for bulk page allocator.

Fixes: 387ba26fb1cb ("mm/page_alloc: add a bulk page allocator")
Cc: <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Signed-off-by: Vasily Averin <vvs-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org>
---
v2: modified according to Shakeel Butt's remarks
---
include/linux/memcontrol.h | 11 +++++++++
mm/memcontrol.c | 48 +++++++++++++++++++++++++++++++++++++-
mm/page_alloc.c | 14 ++++++++++-
3 files changed, 71 insertions(+), 2 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 3096c9a0ee01..990acd70c846 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -810,6 +810,12 @@ static inline void obj_cgroup_put(struct obj_cgroup *objcg)
percpu_ref_put(&objcg->refcnt);
}

+static inline void obj_cgroup_put_many(struct obj_cgroup *objcg,
+ unsigned long nr)
+{
+ percpu_ref_put_many(&objcg->refcnt, nr);
+}
+
static inline void mem_cgroup_put(struct mem_cgroup *memcg)
{
if (memcg)
@@ -1746,4 +1752,9 @@ static inline struct mem_cgroup *mem_cgroup_from_obj(void *p)

#endif /* CONFIG_MEMCG_KMEM */

+bool memcg_bulk_pre_charge_hook(struct obj_cgroup **objcgp, gfp_t gfp,
+ unsigned int nr_pages);
+void memcg_bulk_charge_hook(struct obj_cgroup *objcgp, struct page *page);
+void memcg_bulk_post_charge_hook(struct obj_cgroup *objcg,
+ unsigned int nr_pages);
#endif /* _LINUX_MEMCONTROL_H */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 87e41c3cac10..16fe3384c12c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3239,7 +3239,53 @@ void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size)
refill_obj_stock(objcg, size, true);
}

-#endif /* CONFIG_MEMCG_KMEM */
+bool memcg_bulk_pre_charge_hook(struct obj_cgroup **objcgp, gfp_t gfp,
+ unsigned int nr_pages)
+{
+ struct obj_cgroup *objcg = NULL;
+
+ if (!memcg_kmem_enabled() || !(gfp & __GFP_ACCOUNT))
+ return true;
+
+ objcg = get_obj_cgroup_from_current();
+
+ if (objcg && obj_cgroup_charge_pages(objcg, gfp, nr_pages)) {
+ obj_cgroup_put(objcg);
+ return false;
+ }
+ obj_cgroup_get_many(objcg, nr_pages - 1);
+ *objcgp = objcg;
+ return true;
+}
+
+void memcg_bulk_charge_hook(struct obj_cgroup *objcg, struct page *page)
+{
+ page->memcg_data = (unsigned long)objcg | MEMCG_DATA_KMEM;
+}
+
+void memcg_bulk_post_charge_hook(struct obj_cgroup *objcg,
+ unsigned int nr_pages)
+{
+ obj_cgroup_uncharge_pages(objcg, nr_pages);
+ obj_cgroup_put_many(objcg, nr_pages);
+}
+#else /* !CONFIG_MEMCG_KMEM */
+bool memcg_bulk_pre_charge_hook(struct obj_cgroup **objcgp, gfp_t gfp,
+ unsigned int nr_pages)
+{
+ return true;
+}
+
+void memcg_bulk_charge_hook(struct obj_cgroup *objcgp, struct page *page)
+{
+}
+
+void memcg_bulk_post_charge_hook(struct obj_cgroup *objcg,
+ unsigned int nr_pages)
+{
+}
+#endif
+

/*
* Because page_memcg(head) is not set on tails, set it now.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b37435c274cf..eb37177bf507 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5207,6 +5207,8 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid,
gfp_t alloc_gfp;
unsigned int alloc_flags = ALLOC_WMARK_LOW;
int nr_populated = 0, nr_account = 0;
+ unsigned int nr_pre_charge = 0;
+ struct obj_cgroup *objcg = NULL;

/*
* Skip populated array elements to determine if any pages need
@@ -5275,6 +5277,10 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid,
if (unlikely(!zone))
goto failed;

+ nr_pre_charge = nr_pages - nr_populated;
+ if (!memcg_bulk_pre_charge_hook(&objcg, gfp, nr_pre_charge))
+ goto failed;
+
/* Attempt the batch allocation */
local_lock_irqsave(&pagesets.lock, flags);
pcp = this_cpu_ptr(zone->per_cpu_pageset);
@@ -5299,6 +5305,9 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid,
nr_account++;

prep_new_page(page, 0, gfp, 0);
+ if (objcg)
+ memcg_bulk_charge_hook(objcg, page);
+
if (page_list)
list_add(&page->lru, page_list);
else
@@ -5310,13 +5319,16 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid,

__count_zid_vm_events(PGALLOC, zone_idx(zone), nr_account);
zone_statistics(ac.preferred_zoneref->zone, zone, nr_account);
+ if (objcg)
+ memcg_bulk_post_charge_hook(objcg, nr_pre_charge - nr_account);

out:
return nr_populated;

failed_irq:
local_unlock_irqrestore(&pagesets.lock, flags);
-
+ if (objcg)
+ memcg_bulk_post_charge_hook(objcg, nr_pre_charge);
failed:
page = __alloc_pages(gfp, 0, preferred_nid, nodemask);
if (page) {
--
2.31.1