[PATCH] cpusets: confine pdflush to its cpuset

[linux-2.6.git] / mm / pdflush.c

diff --git a/mm/pdflush.c b/mm/pdflush.c
index d6781951267eb654a522529658aaa06199d1772f..52822c98c489c36bc30e24871eef936766b5c784 100644 (file)
--- a/mm/pdflush.c
+++ b/mm/pdflush.c
@@ -20,6 +20,7 @@
 #include <linux/fs.h>          // Needed by writeback.h
 #include <linux/writeback.h>   // Prototypes pdflush_operation()
 #include <linux/kthread.h>
+#include <linux/cpuset.h>
 
 
 /*
@@ -170,12 +171,24 @@ static int __pdflush(struct pdflush_work *my_work)
 static int pdflush(void *dummy)
 {
        struct pdflush_work my_work;
+       cpumask_t cpus_allowed;
 
        /*
         * pdflush can spend a lot of time doing encryption via dm-crypt.  We
         * don't want to do that at keventd's priority.
         */
        set_user_nice(current, 0);
+
+       /*
+        * Some configs put our parent kthread in a limited cpuset,
+        * which kthread() overrides, forcing cpus_allowed == CPU_MASK_ALL.
+        * Our needs are more modest - cut back to our cpusets cpus_allowed.
+        * This is needed as pdflush's are dynamically created and destroyed.
+        * The boottime pdflush's are easily placed w/o these 2 lines.
+        */
+       cpus_allowed = cpuset_cpus_allowed(current);
+       set_cpus_allowed(current, cpus_allowed);
+
        return __pdflush(&my_work);
 }