Make the slow work pool configurable

Make the slow work pool configurable through /proc/sys/kernel/slow-work.

 (*) /proc/sys/kernel/slow-work/min-threads

     The minimum number of threads that should be in the pool as long as it is
     in use.  This may be anywhere between 2 and max-threads.

 (*) /proc/sys/kernel/slow-work/max-threads

     The maximum number of threads that should in the pool.  This may be
     anywhere between min-threads and 255 or NR_CPUS * 2, whichever is greater.

 (*) /proc/sys/kernel/slow-work/vslow-percentage

     The percentage of active threads in the pool that may be used to execute
     very slow work items.  This may be between 1 and 99.  The resultant number
     is bounded to between 1 and one fewer than the number of active threads.
     This ensures there is always at least one thread that can process very
     slow work items, and always at least one thread that won't.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/slow-work.h b/include/linux/slow-work.h
index 4dd754af393e..8262809dfa8b 100644
--- a/include/linux/slow-work.h
+++ b/include/linux/slow-work.h
@@ -14,6 +14,8 @@
 
 #ifdef CONFIG_SLOW_WORK
 
+#include <linux/sysctl.h>
+
 struct slow_work;
 
 /*
@@ -83,6 +85,9 @@ extern int slow_work_enqueue(struct slow_work *work);
 extern int slow_work_register_user(void);
 extern void slow_work_unregister_user(void);
 
+#ifdef CONFIG_SYSCTL
+extern ctl_table slow_work_sysctls[];
+#endif
 
 #endif /* CONFIG_SLOW_WORK */
 #endif /* _LINUX_SLOW_WORK_H */