The patch titled
Subject: mm, memcg: unify reclaim retry limits with page allocator
has been added to the -mm tree. Its filename is
mm-memcg-unify-reclaim-retry-limits-with-page-allocator.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memcg-unify-reclaim-retry-limits-with-page-allocator.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcg-unify-reclaim-retry-limits-with-page-allocator.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Chris Down <chris@xxxxxxxxxxxxxx>
Subject: mm, memcg: unify reclaim retry limits with page allocator
Reclaim retries have been set to 5 since the beginning of time in
commit 66e1707bc346 ("Memory controller: add per cgroup LRU and
reclaim"). However, we now have a generally agreed-upon standard for
page reclaim: MAX_RECLAIM_RETRIES (currently 16), added many years later
in commit 0a0337e0d1d1 ("mm, oom: rework oom detection").
In the absence of a compelling reason to declare an OOM earlier in memcg
context than page allocator context, it seems reasonable to supplant
MEM_CGROUP_RECLAIM_RETRIES with MAX_RECLAIM_RETRIES, making the page
allocator and memcg internals more similar in semantics when reclaim
fails to produce results, avoiding premature OOMs or throttling.
Link: http://lkml.kernel.org/r/da557856c9c7654308eaff4eedc1952a95e8df5f.1594640214.git.chris@xxxxxxxxxxxxxx
Signed-off-by: Chris Down <chris@xxxxxxxxxxxxxx>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)
--- a/mm/memcontrol.c~mm-memcg-unify-reclaim-retry-limits-with-page-allocator
+++ a/mm/memcontrol.c
@@ -73,9 +73,6 @@ EXPORT_SYMBOL(memory_cgrp_subsys);
struct mem_cgroup *root_mem_cgroup __read_mostly;
-/* The number of times we should retry reclaim failures before giving up. */
-#define MEM_CGROUP_RECLAIM_RETRIES 5
-
/* Socket memory accounting disabled? */
static bool cgroup_memory_nosocket;
@@ -2540,7 +2537,7 @@ void mem_cgroup_handle_over_high(void)
unsigned long pflags;
unsigned long nr_reclaimed;
unsigned int nr_pages = current->memcg_nr_pages_over_high;
- int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+ int nr_retries = MAX_RECLAIM_RETRIES;
struct mem_cgroup *memcg;
bool in_retry = false;
@@ -2617,7 +2614,7 @@ static int try_charge(struct mem_cgroup
unsigned int nr_pages)
{
unsigned int batch = max(MEMCG_CHARGE_BATCH, nr_pages);
- int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+ int nr_retries = MAX_RECLAIM_RETRIES;
struct mem_cgroup *mem_over_limit;
struct page_counter *counter;
unsigned long nr_reclaimed;
@@ -2736,7 +2733,7 @@ retry:
get_order(nr_pages * PAGE_SIZE));
switch (oom_status) {
case OOM_SUCCESS:
- nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+ nr_retries = MAX_RECLAIM_RETRIES;
goto retry;
case OOM_FAILED:
goto force;
@@ -3396,7 +3393,7 @@ static inline bool memcg_has_children(st
*/
static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
{
- int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+ int nr_retries = MAX_RECLAIM_RETRIES;
/* we call try-to-free pages for make this cgroup empty */
lru_add_drain_all();
@@ -6225,7 +6222,7 @@ static ssize_t memory_high_write(struct
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
- unsigned int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+ unsigned int nr_retries = MAX_RECLAIM_RETRIES;
bool drained = false;
unsigned long high;
int err;
@@ -6273,7 +6270,7 @@ static ssize_t memory_max_write(struct k
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
- unsigned int nr_reclaims = MEM_CGROUP_RECLAIM_RETRIES;
+ unsigned int nr_reclaims = MAX_RECLAIM_RETRIES;
bool drained = false;
unsigned long max;
int err;
_
Patches currently in -mm which might be from chris@xxxxxxxxxxxxxx are
tmpfs-per-superblock-i_ino-support.patch
tmpfs-support-64-bit-inums-per-sb.patch
mm-memcg-reclaim-more-aggressively-before-high-allocator-throttling.patch
mm-memcg-unify-reclaim-retry-limits-with-page-allocator.patch
