The patch titled
Subject: mm: memcg: rename and document global_reclaim()
has been added to the -mm mm-unstable branch. Its filename is
mm-memcg-rename-and-document-global_reclaim.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memcg-rename-and-document-global_reclaim.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Subject: mm: memcg: rename and document global_reclaim()
Date: Wed, 21 Jun 2023 02:30:53 +0000
Evidently, global_reclaim() can be a confusing name. Especially that it
used to exist before with a subtly different definition (removed by commit
b5ead35e7e1d ("mm: vmscan: naming fixes: global_reclaim() and
sane_reclaim()"). It can be interpreted as non-cgroup reclaim, even
though it returns true for cgroup reclaim on the root memcg (through
memory.reclaim).
Rename it to root_reclaim() in an attempt to make it less ambiguous, and
add documentation to it as well as cgroup_reclaim.
Link: https://lkml.kernel.org/r/20230621023053.432374-1-yosryahmed@xxxxxxxxxx
Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Reported-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Closes: https://lore.kernel.org/lkml/20230405200150.GA35884@xxxxxxxxxxx/
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)
--- a/mm/vmscan.c~mm-memcg-rename-and-document-global_reclaim
+++ a/mm/vmscan.c
@@ -429,12 +429,17 @@ void reparent_shrinker_deferred(struct m
up_read(&shrinker_rwsem);
}
+/* Returns true for reclaim through cgroup limits or cgroup interfaces. */
static bool cgroup_reclaim(struct scan_control *sc)
{
return sc->target_mem_cgroup;
}
-static bool global_reclaim(struct scan_control *sc)
+/*
+ * Returns true for reclaim on the root cgroup. This is true for direct
+ * allocator reclaim and reclaim through cgroup interfaces on the root cgroup.
+ */
+static bool root_reclaim(struct scan_control *sc)
{
return !sc->target_mem_cgroup || mem_cgroup_is_root(sc->target_mem_cgroup);
}
@@ -489,7 +494,7 @@ static bool cgroup_reclaim(struct scan_c
return false;
}
-static bool global_reclaim(struct scan_control *sc)
+static bool root_reclaim(struct scan_control *sc)
{
return true;
}
@@ -546,7 +551,7 @@ static void flush_reclaim_state(struct s
* memcg reclaim, to make reporting more accurate and reduce
* underestimation, but it's probably not worth the complexity for now.
*/
- if (current->reclaim_state && global_reclaim(sc)) {
+ if (current->reclaim_state && root_reclaim(sc)) {
sc->nr_reclaimed += current->reclaim_state->reclaimed;
current->reclaim_state->reclaimed = 0;
}
@@ -5325,7 +5330,7 @@ static long get_nr_to_scan(struct lruvec
static unsigned long get_nr_to_reclaim(struct scan_control *sc)
{
/* don't abort memcg reclaim to ensure fairness */
- if (!global_reclaim(sc))
+ if (!root_reclaim(sc))
return -1;
return max(sc->nr_to_reclaim, compact_gap(sc->order));
@@ -5477,7 +5482,7 @@ static void lru_gen_shrink_lruvec(struct
{
struct blk_plug plug;
- VM_WARN_ON_ONCE(global_reclaim(sc));
+ VM_WARN_ON_ONCE(root_reclaim(sc));
VM_WARN_ON_ONCE(!sc->may_writepage || !sc->may_unmap);
lru_add_drain();
@@ -5538,7 +5543,7 @@ static void lru_gen_shrink_node(struct p
struct blk_plug plug;
unsigned long reclaimed = sc->nr_reclaimed;
- VM_WARN_ON_ONCE(!global_reclaim(sc));
+ VM_WARN_ON_ONCE(!root_reclaim(sc));
/*
* Unmapped clean folios are already prioritized. Scanning for more of
@@ -6260,7 +6265,7 @@ static void shrink_lruvec(struct lruvec
bool proportional_reclaim;
struct blk_plug plug;
- if (lru_gen_enabled() && !global_reclaim(sc)) {
+ if (lru_gen_enabled() && !root_reclaim(sc)) {
lru_gen_shrink_lruvec(lruvec, sc);
return;
}
@@ -6501,7 +6506,7 @@ static void shrink_node(pg_data_t *pgdat
struct lruvec *target_lruvec;
bool reclaimable = false;
- if (lru_gen_enabled() && global_reclaim(sc)) {
+ if (lru_gen_enabled() && root_reclaim(sc)) {
lru_gen_shrink_node(pgdat, sc);
return;
}
_
Patches currently in -mm which might be from yosryahmed@xxxxxxxxxx are
mm-zswap-fix-double-invalidate-with-exclusive-loads.patch
mm-memcg-rename-and-document-global_reclaim.patch
mm-vmscan-fix-root-proactive-reclaim-unthrottling-unbalanced-node.patch
