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Date: Fri, 23 Jun 2023 20:13:21 -0700
From: Alexei Starovoitov <alexei.starovoitov@...il.com>
To: daniel@...earbox.net,
andrii@...nel.org,
void@...ifault.com,
houtao@...weicloud.com,
paulmck@...nel.org
Cc: tj@...nel.org,
rcu@...r.kernel.org,
netdev@...r.kernel.org,
bpf@...r.kernel.org,
kernel-team@...com
Subject: [PATCH v2 bpf-next 01/13] bpf: Rename few bpf_mem_alloc fields.
From: Alexei Starovoitov <ast@...nel.org>
Rename:
- struct rcu_head rcu;
- struct llist_head free_by_rcu;
- struct llist_head waiting_for_gp;
- atomic_t call_rcu_in_progress;
+ struct llist_head free_by_rcu_ttrace;
+ struct llist_head waiting_for_gp_ttrace;
+ struct rcu_head rcu_ttrace;
+ atomic_t call_rcu_ttrace_in_progress;
...
- static void do_call_rcu(struct bpf_mem_cache *c)
+ static void do_call_rcu_ttrace(struct bpf_mem_cache *c)
to better indicate intended use.
The 'tasks trace' is shortened to 'ttrace' to reduce verbosity.
No functional changes.
Later patches will add free_by_rcu/waiting_for_gp fields to be used with normal RCU.
Signed-off-by: Alexei Starovoitov <ast@...nel.org>
---
kernel/bpf/memalloc.c | 57 ++++++++++++++++++++++---------------------
1 file changed, 29 insertions(+), 28 deletions(-)
diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c
index 0668bcd7c926..cc5b8adb4c83 100644
--- a/kernel/bpf/memalloc.c
+++ b/kernel/bpf/memalloc.c
@@ -99,10 +99,11 @@ struct bpf_mem_cache {
int low_watermark, high_watermark, batch;
int percpu_size;
- struct rcu_head rcu;
- struct llist_head free_by_rcu;
- struct llist_head waiting_for_gp;
- atomic_t call_rcu_in_progress;
+ /* list of objects to be freed after RCU tasks trace GP */
+ struct llist_head free_by_rcu_ttrace;
+ struct llist_head waiting_for_gp_ttrace;
+ struct rcu_head rcu_ttrace;
+ atomic_t call_rcu_ttrace_in_progress;
};
struct bpf_mem_caches {
@@ -165,18 +166,18 @@ static void alloc_bulk(struct bpf_mem_cache *c, int cnt, int node)
old_memcg = set_active_memcg(memcg);
for (i = 0; i < cnt; i++) {
/*
- * free_by_rcu is only manipulated by irq work refill_work().
+ * free_by_rcu_ttrace is only manipulated by irq work refill_work().
* IRQ works on the same CPU are called sequentially, so it is
* safe to use __llist_del_first() here. If alloc_bulk() is
* invoked by the initial prefill, there will be no running
* refill_work(), so __llist_del_first() is fine as well.
*
- * In most cases, objects on free_by_rcu are from the same CPU.
+ * In most cases, objects on free_by_rcu_ttrace are from the same CPU.
* If some objects come from other CPUs, it doesn't incur any
* harm because NUMA_NO_NODE means the preference for current
* numa node and it is not a guarantee.
*/
- obj = __llist_del_first(&c->free_by_rcu);
+ obj = __llist_del_first(&c->free_by_rcu_ttrace);
if (!obj) {
/* Allocate, but don't deplete atomic reserves that typical
* GFP_ATOMIC would do. irq_work runs on this cpu and kmalloc
@@ -232,10 +233,10 @@ static void free_all(struct llist_node *llnode, bool percpu)
static void __free_rcu(struct rcu_head *head)
{
- struct bpf_mem_cache *c = container_of(head, struct bpf_mem_cache, rcu);
+ struct bpf_mem_cache *c = container_of(head, struct bpf_mem_cache, rcu_ttrace);
- free_all(llist_del_all(&c->waiting_for_gp), !!c->percpu_size);
- atomic_set(&c->call_rcu_in_progress, 0);
+ free_all(llist_del_all(&c->waiting_for_gp_ttrace), !!c->percpu_size);
+ atomic_set(&c->call_rcu_ttrace_in_progress, 0);
}
static void __free_rcu_tasks_trace(struct rcu_head *head)
@@ -254,32 +255,32 @@ static void enque_to_free(struct bpf_mem_cache *c, void *obj)
struct llist_node *llnode = obj;
/* bpf_mem_cache is a per-cpu object. Freeing happens in irq_work.
- * Nothing races to add to free_by_rcu list.
+ * Nothing races to add to free_by_rcu_ttrace list.
*/
- __llist_add(llnode, &c->free_by_rcu);
+ __llist_add(llnode, &c->free_by_rcu_ttrace);
}
-static void do_call_rcu(struct bpf_mem_cache *c)
+static void do_call_rcu_ttrace(struct bpf_mem_cache *c)
{
struct llist_node *llnode, *t;
- if (atomic_xchg(&c->call_rcu_in_progress, 1))
+ if (atomic_xchg(&c->call_rcu_ttrace_in_progress, 1))
return;
- WARN_ON_ONCE(!llist_empty(&c->waiting_for_gp));
- llist_for_each_safe(llnode, t, __llist_del_all(&c->free_by_rcu))
- /* There is no concurrent __llist_add(waiting_for_gp) access.
+ WARN_ON_ONCE(!llist_empty(&c->waiting_for_gp_ttrace));
+ llist_for_each_safe(llnode, t, __llist_del_all(&c->free_by_rcu_ttrace))
+ /* There is no concurrent __llist_add(waiting_for_gp_ttrace) access.
* It doesn't race with llist_del_all either.
- * But there could be two concurrent llist_del_all(waiting_for_gp):
+ * But there could be two concurrent llist_del_all(waiting_for_gp_ttrace):
* from __free_rcu() and from drain_mem_cache().
*/
- __llist_add(llnode, &c->waiting_for_gp);
+ __llist_add(llnode, &c->waiting_for_gp_ttrace);
/* Use call_rcu_tasks_trace() to wait for sleepable progs to finish.
* If RCU Tasks Trace grace period implies RCU grace period, free
* these elements directly, else use call_rcu() to wait for normal
* progs to finish and finally do free_one() on each element.
*/
- call_rcu_tasks_trace(&c->rcu, __free_rcu_tasks_trace);
+ call_rcu_tasks_trace(&c->rcu_ttrace, __free_rcu_tasks_trace);
}
static void free_bulk(struct bpf_mem_cache *c)
@@ -307,7 +308,7 @@ static void free_bulk(struct bpf_mem_cache *c)
/* and drain free_llist_extra */
llist_for_each_safe(llnode, t, llist_del_all(&c->free_llist_extra))
enque_to_free(c, llnode);
- do_call_rcu(c);
+ do_call_rcu_ttrace(c);
}
static void bpf_mem_refill(struct irq_work *work)
@@ -441,13 +442,13 @@ static void drain_mem_cache(struct bpf_mem_cache *c)
/* No progs are using this bpf_mem_cache, but htab_map_free() called
* bpf_mem_cache_free() for all remaining elements and they can be in
- * free_by_rcu or in waiting_for_gp lists, so drain those lists now.
+ * free_by_rcu_ttrace or in waiting_for_gp_ttrace lists, so drain those lists now.
*
- * Except for waiting_for_gp list, there are no concurrent operations
+ * Except for waiting_for_gp_ttrace list, there are no concurrent operations
* on these lists, so it is safe to use __llist_del_all().
*/
- free_all(__llist_del_all(&c->free_by_rcu), percpu);
- free_all(llist_del_all(&c->waiting_for_gp), percpu);
+ free_all(__llist_del_all(&c->free_by_rcu_ttrace), percpu);
+ free_all(llist_del_all(&c->waiting_for_gp_ttrace), percpu);
free_all(__llist_del_all(&c->free_llist), percpu);
free_all(__llist_del_all(&c->free_llist_extra), percpu);
}
@@ -462,7 +463,7 @@ static void free_mem_alloc_no_barrier(struct bpf_mem_alloc *ma)
static void free_mem_alloc(struct bpf_mem_alloc *ma)
{
- /* waiting_for_gp lists was drained, but __free_rcu might
+ /* waiting_for_gp_ttrace lists was drained, but __free_rcu might
* still execute. Wait for it now before we freeing percpu caches.
*
* rcu_barrier_tasks_trace() doesn't imply synchronize_rcu_tasks_trace(),
@@ -535,7 +536,7 @@ void bpf_mem_alloc_destroy(struct bpf_mem_alloc *ma)
*/
irq_work_sync(&c->refill_work);
drain_mem_cache(c);
- rcu_in_progress += atomic_read(&c->call_rcu_in_progress);
+ rcu_in_progress += atomic_read(&c->call_rcu_ttrace_in_progress);
}
/* objcg is the same across cpus */
if (c->objcg)
@@ -550,7 +551,7 @@ void bpf_mem_alloc_destroy(struct bpf_mem_alloc *ma)
c = &cc->cache[i];
irq_work_sync(&c->refill_work);
drain_mem_cache(c);
- rcu_in_progress += atomic_read(&c->call_rcu_in_progress);
+ rcu_in_progress += atomic_read(&c->call_rcu_ttrace_in_progress);
}
}
if (c->objcg)
--
2.34.1
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