1 files changed, 13 insertions, 0 deletions

diff --git a/mm/pdflush.c b/mm/pdflush.c
index d6781951267e..52822c98c489 100644
--- 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);
 }