mm: vmscan: do not disable interrupts on -RT

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 8 insertions, 2 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index dea7abd31098..6911d54ff9c8 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -23,6 +23,7 @@
 #include <linux/file.h>
 #include <linux/writeback.h>
 #include <linux/blkdev.h>
+#include <linux/interrupt.h>
 #include <linux/buffer_head.h>  /* for try_to_release_page(),
                                         buffer_heads_over_limit */
 #include <linux/mm_inline.h>
@@ -1118,7 +1119,7 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
                 }
 
                 nr_reclaimed += nr_freed;
-                local_irq_disable();
+                local_irq_disable_nort();
                 if (current_is_kswapd()) {
                         __count_zone_vm_events(PGSCAN_KSWAPD, zone, nr_scan);
                         __count_vm_events(KSWAPD_STEAL, nr_freed);
@@ -1159,9 +1160,14 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
                         }
                 }
         } while (nr_scanned < max_scan);
+        /*
+         * Non-PREEMPT_RT relies on IRQs-off protecting the page_states
+         * per-CPU data. PREEMPT_RT has that data protected even in
+         * __mod_page_state(), so no need to keep IRQs disabled.
+         */
         spin_unlock(&zone->lru_lock);
 done:
-        local_irq_enable();
+        local_irq_enable_nort();
         pagevec_release(&pvec);
         return nr_reclaimed;
 }