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Subject[ANNOUNCE] v5.16-rc6-rt12
Dear RT folks!

I'm pleased to announce the v5.16-rc6-rt12 patch set.

Changes since v5.16-rc6-rt11:

- The timer_threads struct has been made static. Reported by kernel
test robot.

- The networking patches have been redone. They look different now and
hopefully more attractive to upstream.

- The "Memory controller" (CONFIG_MEMCG) can be enabled again.

Known issues
- netconsole triggers WARN.

- Valentin Schneider reported a few splats on ARM64, see
https://lkml.kernel.org/r/20210810134127.1394269-1-valentin.schneider@arm.com

The delta patch against v5.16-rc6-rt11 is appended below and can be found here:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.16/incr/patch-5.16-rc6-rt11-rt12.patch.xz

You can get this release via the git tree at:

git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v5.16-rc6-rt12

The RT patch against v5.16-rc6 can be found here:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.16/older/patch-5.16-rc6-rt12.patch.xz

The split quilt queue is available at:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.16/older/patches-5.16-rc6-rt12.tar.xz

Sebastian

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index be5cb3360b944..5566dbc7eacd6 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -4003,8 +4003,17 @@ u32 bpf_prog_run_generic_xdp(struct sk_buff *skb, struct xdp_buff *xdp,
void generic_xdp_tx(struct sk_buff *skb, struct bpf_prog *xdp_prog);
int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff *skb);
int netif_rx(struct sk_buff *skb);
-int netif_rx_ni(struct sk_buff *skb);
-int netif_rx_any_context(struct sk_buff *skb);
+
+static inline int netif_rx_ni(struct sk_buff *skb)
+{
+ return netif_rx(skb);
+}
+
+static inline int netif_rx_any_context(struct sk_buff *skb)
+{
+ return netif_rx(skb);
+}
+
int netif_receive_skb(struct sk_buff *skb);
int netif_receive_skb_core(struct sk_buff *skb);
void netif_receive_skb_list(struct list_head *head);
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index cb011f4d0b5dc..c8cb7e697d479 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -297,7 +297,6 @@ struct sk_buff_head {

__u32 qlen;
spinlock_t lock;
- raw_spinlock_t raw_lock;
};

struct sk_buff;
@@ -1954,12 +1953,6 @@ static inline void skb_queue_head_init(struct sk_buff_head *list)
__skb_queue_head_init(list);
}

-static inline void skb_queue_head_init_raw(struct sk_buff_head *list)
-{
- raw_spin_lock_init(&list->raw_lock);
- __skb_queue_head_init(list);
-}
-
static inline void skb_queue_head_init_class(struct sk_buff_head *list,
struct lock_class_key *class)
{
diff --git a/include/trace/events/net.h b/include/trace/events/net.h
index 78c448c6ab4c5..032b431b987b6 100644
--- a/include/trace/events/net.h
+++ b/include/trace/events/net.h
@@ -260,13 +260,6 @@ DEFINE_EVENT(net_dev_rx_verbose_template, netif_rx_entry,
TP_ARGS(skb)
);

-DEFINE_EVENT(net_dev_rx_verbose_template, netif_rx_ni_entry,
-
- TP_PROTO(const struct sk_buff *skb),
-
- TP_ARGS(skb)
-);
-
DECLARE_EVENT_CLASS(net_dev_rx_exit_template,

TP_PROTO(int ret),
@@ -312,13 +305,6 @@ DEFINE_EVENT(net_dev_rx_exit_template, netif_rx_exit,
TP_ARGS(ret)
);

-DEFINE_EVENT(net_dev_rx_exit_template, netif_rx_ni_exit,
-
- TP_PROTO(int ret),
-
- TP_ARGS(ret)
-);
-
DEFINE_EVENT(net_dev_rx_exit_template, netif_receive_skb_list_exit,

TP_PROTO(int ret),
diff --git a/init/Kconfig b/init/Kconfig
index d671799c5f377..4b7bac10c72d3 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -943,7 +943,6 @@ config PAGE_COUNTER

config MEMCG
bool "Memory controller"
- depends on !PREEMPT_RT
select PAGE_COUNTER
select EVENTFD
help
diff --git a/kernel/softirq.c b/kernel/softirq.c
index d685519962e5a..22948c2109f5b 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -1029,7 +1029,7 @@ void raise_timer_softirq(void)
}
#endif

-struct smp_hotplug_thread timer_threads = {
+static struct smp_hotplug_thread timer_threads = {
.store = &timersd,
.setup = timersd_setup,
.thread_should_run = timersd_should_run,
diff --git a/localversion-rt b/localversion-rt
index 05c35cb580779..6e44e540b927b 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt11
+-rt12
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2ed5f2a0879d3..92180f1aa9edc 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -261,8 +261,10 @@ bool mem_cgroup_kmem_disabled(void)
return cgroup_memory_nokmem;
}

+struct memcg_stock_pcp;
static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg,
- unsigned int nr_pages);
+ unsigned int nr_pages,
+ struct memcg_stock_pcp *stock_pcp);

static void obj_cgroup_release(struct percpu_ref *ref)
{
@@ -296,7 +298,7 @@ static void obj_cgroup_release(struct percpu_ref *ref)
nr_pages = nr_bytes >> PAGE_SHIFT;

if (nr_pages)
- obj_cgroup_uncharge_pages(objcg, nr_pages);
+ obj_cgroup_uncharge_pages(objcg, nr_pages, NULL);

spin_lock_irqsave(&css_set_lock, flags);
list_del(&objcg->list);
@@ -671,8 +673,14 @@ void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val)
if (mem_cgroup_disabled())
return;

+ if (IS_ENABLED(CONFIG_PREEMPT_RT))
+ preempt_disable();
+
__this_cpu_add(memcg->vmstats_percpu->state[idx], val);
memcg_rstat_updated(memcg);
+
+ if (IS_ENABLED(CONFIG_PREEMPT_RT))
+ preempt_enable();
}

/* idx can be of type enum memcg_stat_item or node_stat_item. */
@@ -699,6 +707,9 @@ void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
memcg = pn->memcg;

+ if (IS_ENABLED(CONFIG_PREEMPT_RT))
+ preempt_disable();
+
/* Update memcg */
__this_cpu_add(memcg->vmstats_percpu->state[idx], val);

@@ -706,6 +717,9 @@ void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
__this_cpu_add(pn->lruvec_stats_percpu->state[idx], val);

memcg_rstat_updated(memcg);
+
+ if (IS_ENABLED(CONFIG_PREEMPT_RT))
+ preempt_enable();
}

/**
@@ -788,8 +802,13 @@ void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx,
if (mem_cgroup_disabled())
return;

+ if (IS_ENABLED(PREEMPT_RT))
+ preempt_disable();
+
__this_cpu_add(memcg->vmstats_percpu->events[idx], count);
memcg_rstat_updated(memcg);
+ if (IS_ENABLED(PREEMPT_RT))
+ preempt_enable();
}

static unsigned long memcg_events(struct mem_cgroup *memcg, int event)
@@ -810,6 +829,9 @@ static unsigned long memcg_events_local(struct mem_cgroup *memcg, int event)
static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
int nr_pages)
{
+ if (IS_ENABLED(CONFIG_PREEMPT_RT))
+ preempt_disable();
+
/* pagein of a big page is an event. So, ignore page size */
if (nr_pages > 0)
__count_memcg_events(memcg, PGPGIN, 1);
@@ -819,12 +841,19 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
}

__this_cpu_add(memcg->vmstats_percpu->nr_page_events, nr_pages);
+
+ if (IS_ENABLED(CONFIG_PREEMPT_RT))
+ preempt_enable();
}

static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
enum mem_cgroup_events_target target)
{
unsigned long val, next;
+ bool ret = false;
+
+ if (IS_ENABLED(CONFIG_PREEMPT_RT))
+ preempt_disable();

val = __this_cpu_read(memcg->vmstats_percpu->nr_page_events);
next = __this_cpu_read(memcg->vmstats_percpu->targets[target]);
@@ -841,9 +870,11 @@ static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
break;
}
__this_cpu_write(memcg->vmstats_percpu->targets[target], next);
- return true;
+ ret = true;
}
- return false;
+ if (IS_ENABLED(CONFIG_PREEMPT_RT))
+ preempt_enable();
+ return ret;
}

/*
@@ -2091,26 +2122,40 @@ struct obj_stock {
};

struct memcg_stock_pcp {
+ /* Protects memcg_stock_pcp */
+ local_lock_t stock_lock;
struct mem_cgroup *cached; /* this never be root cgroup */
unsigned int nr_pages;
+#ifndef CONFIG_PREEMPTION
+ /* Protects only task_obj */
+ local_lock_t task_obj_lock;
struct obj_stock task_obj;
+#endif
struct obj_stock irq_obj;

struct work_struct work;
unsigned long flags;
#define FLUSHING_CACHED_CHARGE 0
};
-static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
+static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock) = {
+ .stock_lock = INIT_LOCAL_LOCK(stock_lock),
+#ifndef CONFIG_PREEMPTION
+ .task_obj_lock = INIT_LOCAL_LOCK(task_obj_lock),
+#endif
+};
static DEFINE_MUTEX(percpu_charge_mutex);

#ifdef CONFIG_MEMCG_KMEM
-static void drain_obj_stock(struct obj_stock *stock);
+static struct obj_cgroup *drain_obj_stock(struct obj_stock *stock,
+ struct memcg_stock_pcp *stock_pcp);
static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
struct mem_cgroup *root_memcg);

#else
-static inline void drain_obj_stock(struct obj_stock *stock)
+static inline struct obj_cgroup *drain_obj_stock(struct obj_stock *stock,
+ struct memcg_stock_pcp *stock_pcp)
{
+ return NULL;
}
static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
struct mem_cgroup *root_memcg)
@@ -2139,7 +2184,7 @@ static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
if (nr_pages > MEMCG_CHARGE_BATCH)
return ret;

- local_irq_save(flags);
+ local_lock_irqsave(&memcg_stock.stock_lock, flags);

stock = this_cpu_ptr(&memcg_stock);
if (memcg == stock->cached && stock->nr_pages >= nr_pages) {
@@ -2147,7 +2192,7 @@ static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
ret = true;
}

- local_irq_restore(flags);
+ local_unlock_irqrestore(&memcg_stock.stock_lock, flags);

return ret;
}
@@ -2175,38 +2220,43 @@ static void drain_stock(struct memcg_stock_pcp *stock)

static void drain_local_stock(struct work_struct *dummy)
{
- struct memcg_stock_pcp *stock;
- unsigned long flags;
+ struct memcg_stock_pcp *stock_pcp;
+ struct obj_cgroup *old;

/*
* The only protection from cpu hotplug (memcg_hotplug_cpu_dead) vs.
* drain_stock races is that we always operate on local CPU stock
* here with IRQ disabled
*/
- local_irq_save(flags);
+#ifndef CONFIG_PREEMPTION
+ local_lock(&memcg_stock.task_obj_lock);
+ old = drain_obj_stock(&this_cpu_ptr(&memcg_stock)->task_obj, NULL);
+ local_unlock(&memcg_stock.task_obj_lock);
+ if (old)
+ obj_cgroup_put(old);
+#endif

- stock = this_cpu_ptr(&memcg_stock);
- drain_obj_stock(&stock->irq_obj);
- if (in_task())
- drain_obj_stock(&stock->task_obj);
- drain_stock(stock);
- clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
+ local_lock_irq(&memcg_stock.stock_lock);
+ stock_pcp = this_cpu_ptr(&memcg_stock);
+ old = drain_obj_stock(&stock_pcp->irq_obj, stock_pcp);

- local_irq_restore(flags);
+ drain_stock(stock_pcp);
+ clear_bit(FLUSHING_CACHED_CHARGE, &stock_pcp->flags);
+
+ local_unlock_irq(&memcg_stock.stock_lock);
+ if (old)
+ obj_cgroup_put(old);
}

/*
* Cache charges(val) to local per_cpu area.
* This will be consumed by consume_stock() function, later.
*/
-static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
+static void __refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages,
+ struct memcg_stock_pcp *stock)
{
- struct memcg_stock_pcp *stock;
- unsigned long flags;
+ lockdep_assert_held(&stock->stock_lock);

- local_irq_save(flags);
-
- stock = this_cpu_ptr(&memcg_stock);
if (stock->cached != memcg) { /* reset if necessary */
drain_stock(stock);
css_get(&memcg->css);
@@ -2216,8 +2266,20 @@ static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)

if (stock->nr_pages > MEMCG_CHARGE_BATCH)
drain_stock(stock);
+}

- local_irq_restore(flags);
+static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages,
+ struct memcg_stock_pcp *stock_pcp)
+{
+ unsigned long flags;
+
+ if (stock_pcp) {
+ __refill_stock(memcg, nr_pages, stock_pcp);
+ return;
+ }
+ local_lock_irqsave(&memcg_stock.stock_lock, flags);
+ __refill_stock(memcg, nr_pages, this_cpu_ptr(&memcg_stock));
+ local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
}

/*
@@ -2226,7 +2288,7 @@ static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
*/
static void drain_all_stock(struct mem_cgroup *root_memcg)
{
- int cpu, curcpu;
+ int cpu;

/* If someone's already draining, avoid adding running more workers. */
if (!mutex_trylock(&percpu_charge_mutex))
@@ -2237,7 +2299,7 @@ static void drain_all_stock(struct mem_cgroup *root_memcg)
* as well as workers from this path always operate on the local
* per-cpu data. CPU up doesn't touch memcg_stock at all.
*/
- curcpu = get_cpu();
+ cpus_read_lock();
for_each_online_cpu(cpu) {
struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
struct mem_cgroup *memcg;
@@ -2253,14 +2315,10 @@ static void drain_all_stock(struct mem_cgroup *root_memcg)
rcu_read_unlock();

if (flush &&
- !test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
- if (cpu == curcpu)
- drain_local_stock(&stock->work);
- else
- schedule_work_on(cpu, &stock->work);
- }
+ !test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
+ schedule_work_on(cpu, &stock->work);
}
- put_cpu();
+ cpus_read_unlock();
mutex_unlock(&percpu_charge_mutex);
}

@@ -2661,7 +2719,7 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,

done_restock:
if (batch > nr_pages)
- refill_stock(memcg, batch - nr_pages);
+ refill_stock(memcg, batch - nr_pages, NULL);

/*
* If the hierarchy is above the normal consumption range, schedule
@@ -2774,28 +2832,35 @@ static struct mem_cgroup *get_mem_cgroup_from_objcg(struct obj_cgroup *objcg)
* can only be accessed after disabling interrupt. User context code can
* access interrupt object stock, but not vice versa.
*/
-static inline struct obj_stock *get_obj_stock(unsigned long *pflags)
+static inline struct obj_stock *get_obj_stock(unsigned long *pflags,
+ struct memcg_stock_pcp **stock_pcp)
{
struct memcg_stock_pcp *stock;

+#ifndef CONFIG_PREEMPTION
if (likely(in_task())) {
*pflags = 0UL;
- preempt_disable();
+ *stock_pcp = NULL;
+ local_lock(&memcg_stock.task_obj_lock);
stock = this_cpu_ptr(&memcg_stock);
return &stock->task_obj;
}
-
- local_irq_save(*pflags);
+#endif
+ local_lock_irqsave(&memcg_stock.stock_lock, *pflags);
stock = this_cpu_ptr(&memcg_stock);
+ *stock_pcp = stock;
return &stock->irq_obj;
}

-static inline void put_obj_stock(unsigned long flags)
+static inline void put_obj_stock(unsigned long flags,
+ struct memcg_stock_pcp *stock_pcp)
{
- if (likely(in_task()))
- preempt_enable();
+#ifndef CONFIG_PREEMPTION
+ if (likely(!stock_pcp))
+ local_unlock(&memcg_stock.task_obj_lock);
else
- local_irq_restore(flags);
+#endif
+ local_unlock_irqrestore(&memcg_stock.stock_lock, flags);
}

/*
@@ -2973,7 +3038,8 @@ static void memcg_free_cache_id(int id)
* @nr_pages: number of pages to uncharge
*/
static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg,
- unsigned int nr_pages)
+ unsigned int nr_pages,
+ struct memcg_stock_pcp *stock_pcp)
{
struct mem_cgroup *memcg;

@@ -2981,7 +3047,7 @@ static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg,

if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
page_counter_uncharge(&memcg->kmem, nr_pages);
- refill_stock(memcg, nr_pages);
+ refill_stock(memcg, nr_pages, stock_pcp);

css_put(&memcg->css);
}
@@ -3055,7 +3121,7 @@ void __memcg_kmem_uncharge_page(struct page *page, int order)
return;

objcg = __folio_objcg(folio);
- obj_cgroup_uncharge_pages(objcg, nr_pages);
+ obj_cgroup_uncharge_pages(objcg, nr_pages, NULL);
folio->memcg_data = 0;
obj_cgroup_put(objcg);
}
@@ -3063,17 +3129,21 @@ void __memcg_kmem_uncharge_page(struct page *page, int order)
void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
enum node_stat_item idx, int nr)
{
+ struct memcg_stock_pcp *stock_pcp;
unsigned long flags;
- struct obj_stock *stock = get_obj_stock(&flags);
+ struct obj_cgroup *old = NULL;
+ struct obj_stock *stock;
int *bytes;

+ stock = get_obj_stock(&flags, &stock_pcp);
/*
* Save vmstat data in stock and skip vmstat array update unless
* accumulating over a page of vmstat data or when pgdat or idx
* changes.
*/
if (stock->cached_objcg != objcg) {
- drain_obj_stock(stock);
+ old = drain_obj_stock(stock, stock_pcp);
+
obj_cgroup_get(objcg);
stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
? atomic_xchg(&objcg->nr_charged_bytes, 0) : 0;
@@ -3117,38 +3187,43 @@ void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
if (nr)
mod_objcg_mlstate(objcg, pgdat, idx, nr);

- put_obj_stock(flags);
+ put_obj_stock(flags, stock_pcp);
+ if (old)
+ obj_cgroup_put(old);
}

static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
{
+ struct memcg_stock_pcp *stock_pcp;
unsigned long flags;
- struct obj_stock *stock = get_obj_stock(&flags);
+ struct obj_stock *stock;
bool ret = false;

+ stock = get_obj_stock(&flags, &stock_pcp);
if (objcg == stock->cached_objcg && stock->nr_bytes >= nr_bytes) {
stock->nr_bytes -= nr_bytes;
ret = true;
}

- put_obj_stock(flags);
+ put_obj_stock(flags, stock_pcp);

return ret;
}

-static void drain_obj_stock(struct obj_stock *stock)
+static struct obj_cgroup *drain_obj_stock(struct obj_stock *stock,
+ struct memcg_stock_pcp *stock_pcp)
{
struct obj_cgroup *old = stock->cached_objcg;

if (!old)
- return;
+ return NULL;

if (stock->nr_bytes) {
unsigned int nr_pages = stock->nr_bytes >> PAGE_SHIFT;
unsigned int nr_bytes = stock->nr_bytes & (PAGE_SIZE - 1);

if (nr_pages)
- obj_cgroup_uncharge_pages(old, nr_pages);
+ obj_cgroup_uncharge_pages(old, nr_pages, stock_pcp);

/*
* The leftover is flushed to the centralized per-memcg value.
@@ -3183,8 +3258,8 @@ static void drain_obj_stock(struct obj_stock *stock)
stock->cached_pgdat = NULL;
}

- obj_cgroup_put(old);
stock->cached_objcg = NULL;
+ return old;
}

static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
@@ -3192,11 +3267,13 @@ static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
{
struct mem_cgroup *memcg;

+#ifndef CONFIG_PREEMPTION
if (in_task() && stock->task_obj.cached_objcg) {
memcg = obj_cgroup_memcg(stock->task_obj.cached_objcg);
if (memcg && mem_cgroup_is_descendant(memcg, root_memcg))
return true;
}
+#endif
if (stock->irq_obj.cached_objcg) {
memcg = obj_cgroup_memcg(stock->irq_obj.cached_objcg);
if (memcg && mem_cgroup_is_descendant(memcg, root_memcg))
@@ -3209,12 +3286,15 @@ static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes,
bool allow_uncharge)
{
+ struct memcg_stock_pcp *stock_pcp;
unsigned long flags;
- struct obj_stock *stock = get_obj_stock(&flags);
+ struct obj_stock *stock;
unsigned int nr_pages = 0;
+ struct obj_cgroup *old = NULL;

+ stock = get_obj_stock(&flags, &stock_pcp);
if (stock->cached_objcg != objcg) { /* reset if necessary */
- drain_obj_stock(stock);
+ old = drain_obj_stock(stock, stock_pcp);
obj_cgroup_get(objcg);
stock->cached_objcg = objcg;
stock->nr_bytes = atomic_read(&objcg->nr_charged_bytes)
@@ -3228,10 +3308,12 @@ static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes,
stock->nr_bytes &= (PAGE_SIZE - 1);
}

- put_obj_stock(flags);
+ put_obj_stock(flags, stock_pcp);
+ if (old)
+ obj_cgroup_put(old);

if (nr_pages)
- obj_cgroup_uncharge_pages(objcg, nr_pages);
+ obj_cgroup_uncharge_pages(objcg, nr_pages, NULL);
}

int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size)
@@ -5645,12 +5727,14 @@ static int mem_cgroup_move_account(struct page *page,
ret = 0;
nid = folio_nid(folio);

- local_irq_disable();
+ if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+ local_irq_disable();
mem_cgroup_charge_statistics(to, nr_pages);
memcg_check_events(to, nid);
mem_cgroup_charge_statistics(from, -nr_pages);
memcg_check_events(from, nid);
- local_irq_enable();
+ if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+ local_irq_enable();
out_unlock:
folio_unlock(folio);
out:
@@ -6670,10 +6754,12 @@ static int charge_memcg(struct folio *folio, struct mem_cgroup *memcg,
css_get(&memcg->css);
commit_charge(folio, memcg);

- local_irq_disable();
+ if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+ local_irq_disable();
mem_cgroup_charge_statistics(memcg, nr_pages);
memcg_check_events(memcg, folio_nid(folio));
- local_irq_enable();
+ if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+ local_irq_enable();
out:
return ret;
}
@@ -6785,11 +6871,20 @@ static void uncharge_batch(const struct uncharge_gather *ug)
memcg_oom_recover(ug->memcg);
}

- local_irq_save(flags);
- __count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
- __this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, ug->nr_memory);
- memcg_check_events(ug->memcg, ug->nid);
- local_irq_restore(flags);
+ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) {
+ local_irq_save(flags);
+ __count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
+ __this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, ug->nr_memory);
+ memcg_check_events(ug->memcg, ug->nid);
+ local_irq_restore(flags);
+ } else {
+ preempt_disable();
+ __count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
+ __this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, ug->nr_memory);
+ preempt_enable();
+
+ memcg_check_events(ug->memcg, ug->nid);
+ }

/* drop reference from uncharge_folio */
css_put(&ug->memcg->css);
@@ -6930,10 +7025,12 @@ void mem_cgroup_migrate(struct folio *old, struct folio *new)
css_get(&memcg->css);
commit_charge(new, memcg);

- local_irq_save(flags);
+ if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+ local_irq_save(flags);
mem_cgroup_charge_statistics(memcg, nr_pages);
memcg_check_events(memcg, folio_nid(new));
- local_irq_restore(flags);
+ if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+ local_irq_restore(flags);
}

DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key);
@@ -7017,7 +7114,7 @@ void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)

mod_memcg_state(memcg, MEMCG_SOCK, -nr_pages);

- refill_stock(memcg, nr_pages);
+ refill_stock(memcg, nr_pages, NULL);
}

static int __init cgroup_memory(char *s)
@@ -7157,8 +7254,10 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
* i_pages lock which is taken with interrupts-off. It is
* important here to have the interrupts disabled because it is the
* only synchronisation we have for updating the per-CPU variables.
+ * On PREEMPT_RT interrupts are never disabled and the updates to per-CPU
+ * variables are synchronised by keeping preemption disabled.
*/
- VM_BUG_ON(!irqs_disabled());
+ VM_BUG_ON(!IS_ENABLED(CONFIG_PREEMPT_RT) && !irqs_disabled());
mem_cgroup_charge_statistics(memcg, -nr_entries);
memcg_check_events(memcg, page_to_nid(page));

diff --git a/net/core/dev.c b/net/core/dev.c
index 0179312d11c43..250e90116888e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -222,18 +222,38 @@ static inline struct hlist_head *dev_index_hash(struct net *net, int ifindex)
return &net->dev_index_head[ifindex & (NETDEV_HASHENTRIES - 1)];
}

-static inline void rps_lock(struct softnet_data *sd)
+static inline void rps_lock_irqsave(struct softnet_data *sd,
+ unsigned long *flags)
{
-#ifdef CONFIG_RPS
- raw_spin_lock(&sd->input_pkt_queue.raw_lock);
-#endif
+ if (IS_ENABLED(CONFIG_RPS))
+ spin_lock_irqsave(&sd->input_pkt_queue.lock, *flags);
+ else if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+ local_irq_save(*flags);
}

-static inline void rps_unlock(struct softnet_data *sd)
+static inline void rps_lock_irq_disable(struct softnet_data *sd)
{
-#ifdef CONFIG_RPS
- raw_spin_unlock(&sd->input_pkt_queue.raw_lock);
-#endif
+ if (IS_ENABLED(CONFIG_RPS))
+ spin_lock_irq(&sd->input_pkt_queue.lock);
+ else if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+ local_irq_disable();
+}
+
+static inline void rps_unlock_irq_restore(struct softnet_data *sd,
+ unsigned long *flags)
+{
+ if (IS_ENABLED(CONFIG_RPS))
+ spin_unlock_irqrestore(&sd->input_pkt_queue.lock, *flags);
+ else if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+ local_irq_restore(*flags);
+}
+
+static inline void rps_unlock_irq_enable(struct softnet_data *sd)
+{
+ if (IS_ENABLED(CONFIG_RPS))
+ spin_unlock_irq(&sd->input_pkt_queue.lock);
+ else if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+ local_irq_enable();
}

static struct netdev_name_node *netdev_name_node_alloc(struct net_device *dev,
@@ -4646,9 +4666,7 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu,

sd = &per_cpu(softnet_data, cpu);

- local_irq_save(flags);
-
- rps_lock(sd);
+ rps_lock_irqsave(sd, &flags);
if (!netif_running(skb->dev))
goto drop;
qlen = skb_queue_len(&sd->input_pkt_queue);
@@ -4657,27 +4675,30 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu,
enqueue:
__skb_queue_tail(&sd->input_pkt_queue, skb);
input_queue_tail_incr_save(sd, qtail);
- rps_unlock(sd);
- local_irq_restore(flags);
+ rps_unlock_irq_restore(sd, &flags);
return NET_RX_SUCCESS;
}

/* Schedule NAPI for backlog device
* We can use non atomic operation since we own the queue lock
+ * PREEMPT_RT needs to disable interrupts here for
+ * synchronisation needed in napi_schedule.
*/
+ if (IS_ENABLED(CONFIG_PREEMPT_RT))
+ local_irq_disable();
+
if (!__test_and_set_bit(NAPI_STATE_SCHED, &sd->backlog.state)) {
if (!rps_ipi_queued(sd))
____napi_schedule(sd, &sd->backlog);
}
+ if (IS_ENABLED(CONFIG_PREEMPT_RT))
+ local_irq_enable();
goto enqueue;
}

drop:
sd->dropped++;
- rps_unlock(sd);
-
- local_irq_restore(flags);
- preempt_check_resched_rt();
+ rps_unlock_irq_restore(sd, &flags);

atomic_long_inc(&skb->dev->rx_dropped);
kfree_skb(skb);
@@ -4918,7 +4939,6 @@ static int netif_rx_internal(struct sk_buff *skb)
struct rps_dev_flow voidflow, *rflow = &voidflow;
int cpu;

- migrate_disable();
rcu_read_lock();

cpu = get_rps_cpu(skb->dev, skb, &rflow);
@@ -4928,14 +4948,12 @@ static int netif_rx_internal(struct sk_buff *skb)
ret = enqueue_to_backlog(skb, cpu, &rflow->last_qtail);

rcu_read_unlock();
- migrate_enable();
} else
#endif
{
unsigned int qtail;

- ret = enqueue_to_backlog(skb, get_cpu_light(), &qtail);
- put_cpu_light();
+ ret = enqueue_to_backlog(skb, smp_processor_id(), &qtail);
}
return ret;
}
@@ -4959,45 +4977,17 @@ int netif_rx(struct sk_buff *skb)
{
int ret;

+ local_bh_disable();
trace_netif_rx_entry(skb);

ret = netif_rx_internal(skb);
trace_netif_rx_exit(ret);
+ local_bh_enable();

return ret;
}
EXPORT_SYMBOL(netif_rx);

-int netif_rx_ni(struct sk_buff *skb)
-{
- int err;
-
- trace_netif_rx_ni_entry(skb);
-
- local_bh_disable();
- err = netif_rx_internal(skb);
- local_bh_enable();
- trace_netif_rx_ni_exit(err);
-
- return err;
-}
-EXPORT_SYMBOL(netif_rx_ni);
-
-int netif_rx_any_context(struct sk_buff *skb)
-{
- /*
- * If invoked from contexts which do not invoke bottom half
- * processing either at return from interrupt or when softrqs are
- * reenabled, use netif_rx_ni() which invokes bottomhalf processing
- * directly.
- */
- if (in_interrupt())
- return netif_rx(skb);
- else
- return netif_rx_ni(skb);
-}
-EXPORT_SYMBOL(netif_rx_any_context);
-
static __latent_entropy void net_tx_action(struct softirq_action *h)
{
struct softnet_data *sd = this_cpu_ptr(&softnet_data);
@@ -5769,8 +5759,7 @@ static void flush_backlog(struct work_struct *work)
local_bh_disable();
sd = this_cpu_ptr(&softnet_data);

- local_irq_disable();
- rps_lock(sd);
+ rps_lock_irq_disable(sd);
skb_queue_walk_safe(&sd->input_pkt_queue, skb, tmp) {
if (skb->dev->reg_state == NETREG_UNREGISTERING) {
__skb_unlink(skb, &sd->input_pkt_queue);
@@ -5778,8 +5767,7 @@ static void flush_backlog(struct work_struct *work)
input_queue_head_incr(sd);
}
}
- rps_unlock(sd);
- local_irq_enable();
+ rps_unlock_irq_enable(sd);

skb_queue_walk_safe(&sd->process_queue, skb, tmp) {
if (skb->dev->reg_state == NETREG_UNREGISTERING) {
@@ -5797,16 +5785,14 @@ static bool flush_required(int cpu)
struct softnet_data *sd = &per_cpu(softnet_data, cpu);
bool do_flush;

- local_irq_disable();
- rps_lock(sd);
+ rps_lock_irq_disable(sd);

/* as insertion into process_queue happens with the rps lock held,
* process_queue access may race only with dequeue
*/
do_flush = !skb_queue_empty(&sd->input_pkt_queue) ||
!skb_queue_empty_lockless(&sd->process_queue);
- rps_unlock(sd);
- local_irq_enable();
+ rps_unlock_irq_enable(sd);

return do_flush;
#endif
@@ -6467,8 +6453,7 @@ static int process_backlog(struct napi_struct *napi, int quota)

}

- local_irq_disable();
- rps_lock(sd);
+ rps_lock_irq_disable(sd);
if (skb_queue_empty(&sd->input_pkt_queue)) {
/*
* Inline a custom version of __napi_complete().
@@ -6484,8 +6469,7 @@ static int process_backlog(struct napi_struct *napi, int quota)
skb_queue_splice_tail_init(&sd->input_pkt_queue,
&sd->process_queue);
}
- rps_unlock(sd);
- local_irq_enable();
+ rps_unlock_irq_enable(sd);
}

return work;
@@ -11351,7 +11335,7 @@ static int dev_cpu_dead(unsigned int oldcpu)
netif_rx_ni(skb);
input_queue_head_incr(oldsd);
}
- while ((skb = __skb_dequeue(&oldsd->input_pkt_queue))) {
+ while ((skb = skb_dequeue(&oldsd->input_pkt_queue))) {
netif_rx_ni(skb);
input_queue_head_incr(oldsd);
}
@@ -11667,7 +11651,7 @@ static int __init net_dev_init(void)

INIT_WORK(flush, flush_backlog);

- skb_queue_head_init_raw(&sd->input_pkt_queue);
+ skb_queue_head_init(&sd->input_pkt_queue);
skb_queue_head_init(&sd->process_queue);
#ifdef CONFIG_XFRM_OFFLOAD
skb_queue_head_init(&sd->xfrm_backlog);
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