lkml.org 
[lkml]   [2013]   [Mar]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH RFC] vm: Adjust ifdef for TINY_RCU
There is an ifdef in page_cache_get_speculative() that checks for !SMP
and TREE_RCU, which has been an impossible combination since the advent
of TINY_RCU. The ifdef enables a fastpath that is valid when preemption
is disabled by rcu_read_lock() in UP systems, which is the case when
TINY_RCU is enabled. This commit therefore adjusts the ifdef to generate
the fastpath when TINY_RCU is enabled.

Reported-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 0e38e13..e3dea75 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -149,7 +149,7 @@ static inline int page_cache_get_speculative(struct page *page)
{
VM_BUG_ON(in_interrupt());

-#if !defined(CONFIG_SMP) && defined(CONFIG_TREE_RCU)
+#ifdef CONFIG_TINY_RCU
# ifdef CONFIG_PREEMPT_COUNT
VM_BUG_ON(!in_atomic());
# endif


\
 
 \ /
  Last update: 2013-03-04 21:03    [W:0.028 / U:0.344 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site