[PATCH 5/8] mm: memcontrol: teach uncharge_list to deal with kmem pages

From: Vladimir Davydov
Date: Mon May 23 2016 - 08:53:52 EST


Page table pages are batched-freed in release_pages on most
architectures. If we want to charge them to kmemcg (this is what is done
later in this series), we need to teach mem_cgroup_uncharge_list to
handle kmem pages.

Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
---
mm/memcontrol.c | 42 ++++++++++++++++++++++++------------------
1 file changed, 24 insertions(+), 18 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 482b4a0c97e4..89a421ee4713 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5432,15 +5432,18 @@ void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg,

static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout,
unsigned long nr_anon, unsigned long nr_file,
- unsigned long nr_huge, struct page *dummy_page)
+ unsigned long nr_huge, unsigned long nr_kmem,
+ struct page *dummy_page)
{
- unsigned long nr_pages = nr_anon + nr_file;
+ unsigned long nr_pages = nr_anon + nr_file + nr_kmem;
unsigned long flags;

if (!mem_cgroup_is_root(memcg)) {
page_counter_uncharge(&memcg->memory, nr_pages);
if (do_memsw_account())
page_counter_uncharge(&memcg->memsw, nr_pages);
+ if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && nr_kmem)
+ page_counter_uncharge(&memcg->kmem, nr_kmem);
memcg_oom_recover(memcg);
}

@@ -5463,6 +5466,7 @@ static void uncharge_list(struct list_head *page_list)
unsigned long nr_anon = 0;
unsigned long nr_file = 0;
unsigned long nr_huge = 0;
+ unsigned long nr_kmem = 0;
unsigned long pgpgout = 0;
struct list_head *next;
struct page *page;
@@ -5473,8 +5477,6 @@ static void uncharge_list(struct list_head *page_list)
*/
next = page_list->next;
do {
- unsigned int nr_pages = 1;
-
page = list_entry(next, struct page, lru);
next = page->lru.next;

@@ -5493,31 +5495,35 @@ static void uncharge_list(struct list_head *page_list)
if (memcg != page->mem_cgroup) {
if (memcg) {
uncharge_batch(memcg, pgpgout, nr_anon, nr_file,
- nr_huge, page);
- pgpgout = nr_anon = nr_file = nr_huge = 0;
+ nr_huge, nr_kmem, page);
+ pgpgout = nr_anon = nr_file =
+ nr_huge = nr_kmem = 0;
}
memcg = page->mem_cgroup;
}

- if (PageTransHuge(page)) {
- nr_pages <<= compound_order(page);
- VM_BUG_ON_PAGE(!PageTransHuge(page), page);
- nr_huge += nr_pages;
- }
+ if (!PageKmemcg(page)) {
+ unsigned int nr_pages = 1;

- if (PageAnon(page))
- nr_anon += nr_pages;
- else
- nr_file += nr_pages;
+ if (PageTransHuge(page)) {
+ nr_pages <<= compound_order(page);
+ VM_BUG_ON_PAGE(!PageTransHuge(page), page);
+ nr_huge += nr_pages;
+ }
+ if (PageAnon(page))
+ nr_anon += nr_pages;
+ else
+ nr_file += nr_pages;
+ pgpgout++;
+ } else
+ nr_kmem += 1 << compound_order(page);

page->mem_cgroup = NULL;
-
- pgpgout++;
} while (next != page_list);

if (memcg)
uncharge_batch(memcg, pgpgout, nr_anon, nr_file,
- nr_huge, page);
+ nr_huge, nr_kmem, page);
}

/**
--
2.1.4