LU-9558 libcfs: handle hotplug state machine

Install the callbacks via the state machine. No functional change.
Lustre was ported to this in linux kernel 4.10

Linux-commit: 7b737965b33188bd3dbb44e938535c4006d97fbb

Lustre was ported to this API in linux kernel 4.10

Change-Id: I4d8dfdf97051f406b2ac5b1cf6015742996fc216
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/27282
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Olaf Weber <olaf.weber@hpe.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>

diff --git a/libcfs/autoconf/lustre-libcfs.m4 b/libcfs/autoconf/lustre-libcfs.m4
index f81b92a..826fc1a 100644 (file)
--- a/libcfs/autoconf/lustre-libcfs.m4
+++ b/libcfs/autoconf/lustre-libcfs.m4
@@ -644,6 +644,22 @@ get_user_pages_gup_flags, [
 ]) # LIBCFS_GET_USER_PAGES_GUP_FLAGS
 
 #
+# Kernel version 4.10 commit 7b737965b33188bd3dbb44e938535c4006d97fbb
+# libcfs: Convert to hotplug state machine
+#
+AC_DEFUN([LIBCFS_HOTPLUG_STATE_MACHINE], [
+LB_CHECK_COMPILE([if libcfs supports CPU hotplug state machine],
+cpu_hotplug_state_machine, [
+       #include <linux/cpuhotplug.h>
+],[
+       cpuhp_remove_state(CPUHP_LUSTRE_CFS_DEAD);
+],[
+       AC_DEFINE(HAVE_HOTPLUG_STATE_MACHINE, 1,
+               [hotplug state machine is supported])
+])
+]) # LIBCFS_HOTPLUG_STATE_MACHINE
+
+#
 # LIBCFS_PROG_LINUX
 #
 # LibCFS linux kernel checks
@@ -707,6 +723,8 @@ LIBCFS_GET_USER_PAGES_6ARG
 LIBCFS_STACKTRACE_OPS
 # 4.9
 LIBCFS_GET_USER_PAGES_GUP_FLAGS
+# 4.10
+LIBCFS_HOTPLUG_STATE_MACHINE
 ]) # LIBCFS_PROG_LINUX
 
 #

diff --git a/libcfs/libcfs/linux/linux-cpu.c b/libcfs/libcfs/linux/linux-cpu.c
index 3f4f8e7..a1cb867 100644 (file)
--- a/libcfs/libcfs/linux/linux-cpu.c
+++ b/libcfs/libcfs/linux/linux-cpu.c
@@ -1061,11 +1061,33 @@ cfs_cpt_table_create_pattern(char *pattern)
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
+#ifdef HAVE_HOTPLUG_STATE_MACHINE
+static enum cpuhp_state lustre_cpu_online;
+
+static int cfs_cpu_online(unsigned int cpu)
+{
+       return 0;
+}
+#endif
+
+static int cfs_cpu_dead(unsigned int cpu)
+{
+       bool warn;
+
+       /* if all HTs in a core are offline, it may break affinity */
+       warn = cpumask_any_and(topology_sibling_cpumask(cpu),
+                              cpu_online_mask) >= nr_cpu_ids;
+       CDEBUG(warn ? D_WARNING : D_INFO,
+              "Lustre: can't support CPU plug-out well now, performance and stability could be impacted [CPU %u]\n",
+              cpu);
+       return 0;
+}
+
+#ifndef HAVE_HOTPLUG_STATE_MACHINE
 static int cfs_cpu_notify(struct notifier_block *self, unsigned long action,
                          void *hcpu)
 {
        int cpu = (unsigned long)hcpu;
-       bool warn;
 
        switch (action) {
        case CPU_DEAD:
@@ -1079,13 +1101,7 @@ static int cfs_cpu_notify(struct notifier_block *self, unsigned long action,
                        break;
                }
 
-               /* if all HTs in a core are offline, it may break affinity */
-               warn = cpumask_any_and(topology_sibling_cpumask(cpu),
-                                      cpu_online_mask) >= nr_cpu_ids;
-               CDEBUG(warn ? D_WARNING : D_INFO,
-                      "Lustre: can't support CPU plug-out well now, "
-                      "performance and stability could be impacted"
-                      "[CPU %u action: %lx]\n", cpu, action);
+               cfs_cpu_dead(cpu);
        }
 
        return NOTIFY_OK;
@@ -1095,8 +1111,8 @@ static struct notifier_block cfs_cpu_notifier = {
        .notifier_call  = cfs_cpu_notify,
        .priority       = 0
 };
-
-#endif
+#endif /* !HAVE_HOTPLUG_STATE_MACHINE */
+#endif /* CONFIG_HOTPLUG_CPU */
 
 void cfs_cpu_fini(void)
 {
@@ -1104,17 +1120,41 @@ void cfs_cpu_fini(void)
                cfs_cpt_table_free(cfs_cpt_table);
 
 #ifdef CONFIG_HOTPLUG_CPU
+#ifdef HAVE_HOTPLUG_STATE_MACHINE
+       if (lustre_cpu_online > 0)
+               cpuhp_remove_state_nocalls(lustre_cpu_online);
+       cpuhp_remove_state_nocalls(CPUHP_LUSTRE_CFS_DEAD);
+#else
        unregister_hotcpu_notifier(&cfs_cpu_notifier);
-#endif
+#endif /* !HAVE_HOTPLUG_STATE_MACHINE */
+#endif /* CONFIG_HOTPLUG_CPU */
 }
 
 int cfs_cpu_init(void)
 {
-       LASSERT(cfs_cpt_table == NULL);
+       int ret = -EINVAL;
+
+       LASSERT(!cfs_cpt_table);
 
 #ifdef CONFIG_HOTPLUG_CPU
+#ifdef HAVE_HOTPLUG_STATE_MACHINE
+       ret = cpuhp_setup_state_nocalls(CPUHP_LUSTRE_CFS_DEAD,
+                                       "fs/lustre/cfe:dead", NULL,
+                                       cfs_cpu_dead);
+       if (ret < 0)
+               goto failed;
+       ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+                                       "fs/lustre/cfe:online",
+                                       cfs_cpu_online, NULL);
+       if (ret < 0)
+               goto failed;
+       lustre_cpu_online = ret;
+#else
        register_hotcpu_notifier(&cfs_cpu_notifier);
-#endif
+#endif /* !HAVE_HOTPLUG_STATE_MACHINE */
+#endif /* CONFIG_HOTPLUG_CPU */
+       ret = -EINVAL;
+
        get_online_cpus();
        if (*cpu_pattern != 0) {
                char *cpu_pattern_dup = kstrdup(cpu_pattern, GFP_KERNEL);
@@ -1150,7 +1190,7 @@ int cfs_cpu_init(void)
 failed:
        put_online_cpus();
        cfs_cpu_fini();
-       return -1;
+       return ret;
 }
 
 #endif