<!DOCTYPE html><html><head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<p><br>
</p>
<div class="moz-cite-prefix">On 5/29/26 11:51 AM, Vladimir Riabchun
wrote:<br>
</div>
<blockquote type="cite" cite="mid:b9d4d05af8891e932d869f13c3933c1427ef9049.1780003628.git.vladimir.riabchun@virtuozzo.com">
<pre wrap="" class="moz-quote-pre">We currently have /proc/<pid>/net/rpc/kill-tasks feature for
aborting pending RPC tasks. To fast-stop container, we need
to abort all RPC tasks, so we must iterate over all VE PIDs.
There are several problems with this approach:
1. In real life with cgroups-v2 we just process container
init PID, all other network namespaces are ignored.
2. There is a risk of breaking unrelated NFS connections if a PID,
that was a container process, is reused while we are
stopping container.
3. This may be slow - container might have a lot of processes
and a few network namespaces.
To fix this all, create a per-ve interface for aborting
RPC requests in all VE network namespaces.
<a class="moz-txt-link-freetext" href="https://virtuozzo.atlassian.net/browse/VSTOR-126316">https://virtuozzo.atlassian.net/browse/VSTOR-126316</a>
Feature: improve kill-tasks
Signed-off-by: Vladimir Riabchun <a class="moz-txt-link-rfc2396E" href="mailto:vladimir.riabchun@virtuozzo.com"><vladimir.riabchun@virtuozzo.com></a>
---
include/linux/sunrpc/clnt.h | 2 ++
include/linux/ve.h | 4 ++++
kernel/ve/ve.c | 44 +++++++++++++++++++++++++++++++++++++
net/sunrpc/clnt.c | 3 ++-
net/sunrpc/sunrpc_syms.c | 3 +++
5 files changed, 55 insertions(+), 1 deletion(-)
diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
index 0133aeba248a..0e7c7c9107a2 100644
--- a/include/linux/sunrpc/clnt.h
+++ b/include/linux/sunrpc/clnt.h
@@ -253,6 +253,8 @@ void rpc_clnt_probe_trunked_xprts(struct rpc_clnt *,
const char *rpc_proc_name(const struct rpc_task *task);
+
+void rpc_kill_tasks(struct net *net);
int rpc_task_kill_proc_init(struct net *net);
void rpc_task_kill_proc_fini(struct net *net);
diff --git a/include/linux/ve.h b/include/linux/ve.h
index 224acf012821..95a83c7bc7de 100644
--- a/include/linux/ve.h
+++ b/include/linux/ve.h
@@ -279,6 +279,8 @@ extern bool is_ve_init_net(const struct net *net);
void ve_setup_task(struct task_struct *p, struct ve_struct *ve);
+void ve_set_rpc_kill_fn(void (*fn)(struct net *));
+
#else /* CONFIG_VE */
#include <linux/init_task.h>
#define get_ve(ve) ((void)(ve), NULL)
@@ -336,6 +338,8 @@ static inline int vz_security_protocol_check(struct net *net, int protocol) { re
static inline void ve_setup_task(struct task_struct *p, struct ve_struct *ve) { }
+static inline void ve_set_rpc_kill_fn(void (*fn)(struct net *)) { }
+
#endif /* CONFIG_VE */
struct seq_file;
diff --git a/kernel/ve/ve.c b/kernel/ve/ve.c
index 198c82f010cc..856d7afb9d1c 100644
--- a/kernel/ve/ve.c
+++ b/kernel/ve/ve.c
@@ -113,6 +113,8 @@ EXPORT_SYMBOL(nr_ve);
static DEFINE_IDR(ve_idr);
+static void (*rpc_kill_net_fn)(struct net *);</pre>
</blockquote>
<font face="monospace">Please annotate the function pointer as <b>__rcu</b></font>
<blockquote type="cite" cite="mid:b9d4d05af8891e932d869f13c3933c1427ef9049.1780003628.git.vladimir.riabchun@virtuozzo.com">
<pre wrap="" class="moz-quote-pre">
+
struct ve_struct *get_ve(struct ve_struct *ve)
{
if (ve)
@@ -1713,6 +1715,43 @@ static ssize_t ve_write_ctty(struct kernfs_open_file *of, char *buf,
return ret;
}
+void ve_set_rpc_kill_fn(void (*fn)(struct net *))
+{
+ WRITE_ONCE(rpc_kill_net_fn, fn);</pre>
</blockquote>
<font face="monospace">I would prefer the use of <b>rcu_assign_pointer/rcu_dereference</b> as
already done in other functions of the same file.</font>
<blockquote type="cite" cite="mid:b9d4d05af8891e932d869f13c3933c1427ef9049.1780003628.git.vladimir.riabchun@virtuozzo.com">
<pre wrap="" class="moz-quote-pre">
+ /* ve_rpc_kill_write might be using old function.
+ * rpc_kill_tasks -> NULL is dangerous, block sunrpc exit while we use
+ * functions from this module
+ */
+ synchronize_rcu();
+}
+EXPORT_SYMBOL(ve_set_rpc_kill_fn);
+
+static int ve_rpc_kill_write(struct cgroup_subsys_state *css,
+ struct cftype *cft, u64 val)
+{
+ struct net *net;
+ struct ve_struct *ve = css_to_ve(css);
+ void (*fn)(struct net *net);
+
+ guard(rwsem_read)(&net_rwsem); /* for_each_net protection */
+ guard(rcu)(); /* Begin rpc_kill_net_fn usage section */
+
+ fn = READ_ONCE(rpc_kill_net_fn);
+ if (!fn) {
+ pr_info_ratelimited("SUNRPC module is not loaded.\n");
+ return 0;
+ }
+
+ for_each_net(net) {
+ if (net->owner_ve != ve)
+ continue;
+ /* rpc_kill_tasks is atomic. */
+ fn(net);
+ }
+
+ return 0;
+}
+
static struct cftype ve_cftypes[] = {
{
@@ -1808,6 +1847,11 @@ static struct cftype ve_cftypes[] = {
.flags = CFTYPE_ONLY_ON_ROOT,
.write = ve_write_ctty,
},
+ {
+ .name = "rpc_kill",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .write_u64 = ve_rpc_kill_write,
+ },
{ }
};
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 10ef5d9c2696..d40d59145bec 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -3406,8 +3406,9 @@ rpc_clnt_swap_deactivate(struct rpc_clnt *clnt)
EXPORT_SYMBOL_GPL(rpc_clnt_swap_deactivate);
#endif /* CONFIG_SUNRPC_SWAP */
-static void rpc_kill_tasks(struct net *net)
+void rpc_kill_tasks(struct net *net)
{
+ /* Note: function must be atomic, used under RCU read-lock. */
struct rpc_clnt *clnt;
struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
diff --git a/net/sunrpc/sunrpc_syms.c b/net/sunrpc/sunrpc_syms.c
index bab6cab29405..0cb280569135 100644
--- a/net/sunrpc/sunrpc_syms.c
+++ b/net/sunrpc/sunrpc_syms.c
@@ -13,6 +13,7 @@
#include <linux/uio.h>
#include <linux/unistd.h>
#include <linux/init.h>
+#include <linux/ve.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/clnt.h>
@@ -114,6 +115,7 @@ init_sunrpc(void)
#endif
svc_init_xprt_sock(); /* svc sock transport */
init_socket_xprt(); /* clnt sock transport */
+ ve_set_rpc_kill_fn(rpc_kill_tasks);
return 0;
out5:
@@ -131,6 +133,7 @@ init_sunrpc(void)
static void __exit
cleanup_sunrpc(void)
{
+ ve_set_rpc_kill_fn(NULL);
rpc_sysfs_exit();
rpc_cleanup_clids();
xprt_cleanup_ids();
</pre>
</blockquote>
<pre class="moz-signature" cols="72">--
Best regards, Vasileios Almpanis
Software Developer, Virtuozzo.</pre>
</body>
</html>