From: Andrew Morton <akpm@linux-foundation.org>
To: mm-commits@vger.kernel.org,vbabka@suse.cz,roman.gushchin@linux.dev,muchun.song@linux.dev,mhocko@kernel.org,hannes@cmpxchg.org,bigeasy@linutronix.de,shakeel.butt@linux.dev,akpm@linux-foundation.org
Subject: [merged mm-stable] memcg-do-obj_cgroup_put-inside-drain_obj_stock.patch removed from -mm tree
Date: Sun, 11 May 2025 17:50:24 -0700 [thread overview]
Message-ID: <20250512005024.B9574C4CEE4@smtp.kernel.org> (raw)
The quilt patch titled
Subject: memcg: do obj_cgroup_put inside drain_obj_stock
has been removed from the -mm tree. Its filename was
memcg-do-obj_cgroup_put-inside-drain_obj_stock.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Shakeel Butt <shakeel.butt@linux.dev>
Subject: memcg: do obj_cgroup_put inside drain_obj_stock
Date: Thu, 3 Apr 2025 18:39:10 -0700
Previously we could not call obj_cgroup_put() inside the local lock
because on the put on the last reference, the release function
obj_cgroup_release() may try to re-acquire the local lock. However that
chain has been broken. Now simply do obj_cgroup_put() inside
drain_obj_stock() instead of returning the old objcg.
Link: https://lkml.kernel.org/r/20250404013913.1663035-7-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/memcontrol.c | 37 +++++++++++--------------------------
1 file changed, 11 insertions(+), 26 deletions(-)
--- a/mm/memcontrol.c~memcg-do-obj_cgroup_put-inside-drain_obj_stock
+++ a/mm/memcontrol.c
@@ -1785,7 +1785,7 @@ static DEFINE_PER_CPU(struct memcg_stock
};
static DEFINE_MUTEX(percpu_charge_mutex);
-static struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock);
+static void drain_obj_stock(struct memcg_stock_pcp *stock);
static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
struct mem_cgroup *root_memcg);
@@ -1859,7 +1859,6 @@ static void drain_stock(struct memcg_sto
static void drain_local_stock(struct work_struct *dummy)
{
struct memcg_stock_pcp *stock;
- struct obj_cgroup *old = NULL;
unsigned long flags;
/*
@@ -1870,12 +1869,11 @@ static void drain_local_stock(struct wor
local_lock_irqsave(&memcg_stock.stock_lock, flags);
stock = this_cpu_ptr(&memcg_stock);
- old = drain_obj_stock(stock);
+ drain_obj_stock(stock);
drain_stock(stock);
clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
- obj_cgroup_put(old);
}
static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
@@ -1958,18 +1956,16 @@ void drain_all_stock(struct mem_cgroup *
static int memcg_hotplug_cpu_dead(unsigned int cpu)
{
struct memcg_stock_pcp *stock;
- struct obj_cgroup *old;
unsigned long flags;
stock = &per_cpu(memcg_stock, cpu);
/* drain_obj_stock requires stock_lock */
local_lock_irqsave(&memcg_stock.stock_lock, flags);
- old = drain_obj_stock(stock);
+ drain_obj_stock(stock);
local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
drain_stock(stock);
- obj_cgroup_put(old);
return 0;
}
@@ -2766,24 +2762,20 @@ void __memcg_kmem_uncharge_page(struct p
}
/* Replace the stock objcg with objcg, return the old objcg */
-static struct obj_cgroup *replace_stock_objcg(struct memcg_stock_pcp *stock,
- struct obj_cgroup *objcg)
+static void replace_stock_objcg(struct memcg_stock_pcp *stock,
+ struct obj_cgroup *objcg)
{
- struct obj_cgroup *old = NULL;
-
- old = drain_obj_stock(stock);
+ drain_obj_stock(stock);
obj_cgroup_get(objcg);
stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
WRITE_ONCE(stock->cached_objcg, objcg);
- return old;
}
static void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
enum node_stat_item idx, int nr)
{
struct memcg_stock_pcp *stock;
- struct obj_cgroup *old = NULL;
unsigned long flags;
int *bytes;
@@ -2796,7 +2788,7 @@ static void mod_objcg_state(struct obj_c
* changes.
*/
if (READ_ONCE(stock->cached_objcg) != objcg) {
- old = replace_stock_objcg(stock, objcg);
+ replace_stock_objcg(stock, objcg);
stock->cached_pgdat = pgdat;
} else if (stock->cached_pgdat != pgdat) {
/* Flush the existing cached vmstat data */
@@ -2837,7 +2829,6 @@ static void mod_objcg_state(struct obj_c
__mod_objcg_mlstate(objcg, pgdat, idx, nr);
local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
- obj_cgroup_put(old);
}
static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
@@ -2859,12 +2850,12 @@ static bool consume_obj_stock(struct obj
return ret;
}
-static struct obj_cgroup *drain_obj_stock(struct memcg_stock_pcp *stock)
+static void drain_obj_stock(struct memcg_stock_pcp *stock)
{
struct obj_cgroup *old = READ_ONCE(stock->cached_objcg);
if (!old)
- return NULL;
+ return;
if (stock->nr_bytes) {
unsigned int nr_pages = stock->nr_bytes >> PAGE_SHIFT;
@@ -2917,11 +2908,7 @@ static struct obj_cgroup *drain_obj_stoc
}
WRITE_ONCE(stock->cached_objcg, NULL);
- /*
- * The `old' objects needs to be released by the caller via
- * obj_cgroup_put() outside of memcg_stock_pcp::stock_lock.
- */
- return old;
+ obj_cgroup_put(old);
}
static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
@@ -2943,7 +2930,6 @@ static void refill_obj_stock(struct obj_
bool allow_uncharge)
{
struct memcg_stock_pcp *stock;
- struct obj_cgroup *old = NULL;
unsigned long flags;
unsigned int nr_pages = 0;
@@ -2951,7 +2937,7 @@ static void refill_obj_stock(struct obj_
stock = this_cpu_ptr(&memcg_stock);
if (READ_ONCE(stock->cached_objcg) != objcg) { /* reset if necessary */
- old = replace_stock_objcg(stock, objcg);
+ replace_stock_objcg(stock, objcg);
allow_uncharge = true; /* Allow uncharge when objcg changes */
}
stock->nr_bytes += nr_bytes;
@@ -2962,7 +2948,6 @@ static void refill_obj_stock(struct obj_
}
local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
- obj_cgroup_put(old);
if (nr_pages)
obj_cgroup_uncharge_pages(objcg, nr_pages);
_
Patches currently in -mm which might be from shakeel.butt@linux.dev are
memcg-introduce-non-blocking-limit-setting-option.patch
memcg-introduce-non-blocking-limit-setting-option-v3.patch
memcg-simplify-consume_stock.patch
memcg-separate-local_trylock-for-memcg-and-obj.patch
memcg-completely-decouple-memcg-and-obj-stocks.patch
memcg-no-irq-disable-for-memcg-stock-lock.patch
reply other threads:[~2025-05-12 0:50 UTC|newest]
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