From: Sha Zhengju <handai.szj@xxxxxxxxxx>
Similar to dirty page, we add per cgroup writeback pages accounting. The lock
rule still is:
mem_cgroup_begin_update_page_stat()
modify page WRITEBACK stat
mem_cgroup_update_page_stat()
mem_cgroup_end_update_page_stat()
There're two writeback interfaces to modify: test_{clear/set}_page_writeback().
Lock order:
--> memcg->move_lock
--> mapping->tree_lock
Signed-off-by: Sha Zhengju <handai.szj@xxxxxxxxxx>
---
include/linux/memcontrol.h | 1 +
mm/memcontrol.c | 5 +++++
mm/page-writeback.c | 15 +++++++++++++++
3 files changed, 21 insertions(+)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index f952be6..ccd35d8 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -43,6 +43,7 @@ enum mem_cgroup_stat_index {
MEM_CGROUP_STAT_RSS_HUGE, /* # of pages charged as anon huge */
MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
MEM_CGROUP_STAT_FILE_DIRTY, /* # of dirty pages in page cache */
+ MEM_CGROUP_STAT_WRITEBACK, /* # of pages under writeback */
MEM_CGROUP_STAT_SWAP, /* # of pages, swapped out */
MEM_CGROUP_STAT_NSTATS,
};
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 8f3e514..6c18a6d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -91,6 +91,7 @@ static const char * const mem_cgroup_stat_names[] = {
"rss_huge",
"mapped_file",
"dirty",
+ "writeback",
"swap",
};
@@ -3812,6 +3813,10 @@ static int mem_cgroup_move_account(struct page *page,
mem_cgroup_move_account_page_stat(from, to, nr_pages,
MEM_CGROUP_STAT_FILE_DIRTY);
+ if (PageWriteback(page))
+ mem_cgroup_move_account_page_stat(from, to, nr_pages,
+ MEM_CGROUP_STAT_WRITEBACK);
+
mem_cgroup_charge_statistics(from, page, anon, -nr_pages);
/* caller should have done css_get */
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index a09f518..2fa6a52 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2008,11 +2008,17 @@ EXPORT_SYMBOL(account_page_dirtied);
/*
* Helper function for set_page_writeback family.
+ *
+ * The caller must hold mem_cgroup_begin/end_update_page_stat() lock
+ * while calling this function.
+ * See test_set_page_writeback for example.
+ *
* NOTE: Unlike account_page_dirtied this does not rely on being atomic
* wrt interrupts.
*/
void account_page_writeback(struct page *page)
{
+ mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_WRITEBACK);
inc_zone_page_state(page, NR_WRITEBACK);
}
EXPORT_SYMBOL(account_page_writeback);
@@ -2243,7 +2249,10 @@ int test_clear_page_writeback(struct page *page)
{
struct address_space *mapping = page_mapping(page);
int ret;
+ bool locked;
+ unsigned long memcg_flags;
+ mem_cgroup_begin_update_page_stat(page, &locked, &memcg_flags);
if (mapping) {
struct backing_dev_info *bdi = mapping->backing_dev_info;
unsigned long flags;
@@ -2264,9 +2273,11 @@ int test_clear_page_writeback(struct page *page)
ret = TestClearPageWriteback(page);
}
if (ret) {
+ mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_WRITEBACK);
dec_zone_page_state(page, NR_WRITEBACK);
inc_zone_page_state(page, NR_WRITTEN);
}
+ mem_cgroup_end_update_page_stat(page, &locked, &memcg_flags);
return ret;
}
@@ -2274,7 +2285,10 @@ int test_set_page_writeback(struct page *page)
{
struct address_space *mapping = page_mapping(page);
int ret;
+ bool locked;
+ unsigned long flags;
+ mem_cgroup_begin_update_page_stat(page, &locked, &flags);
if (mapping) {
struct backing_dev_info *bdi = mapping->backing_dev_info;
unsigned long flags;
@@ -2301,6 +2315,7 @@ int test_set_page_writeback(struct page *page)
}
if (!ret)
account_page_writeback(page);
+ mem_cgroup_end_update_page_stat(page, &locked, &flags);
return ret;
}
--
1.7.9.5
--
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