From 7ccaba5314caf3a2b1052edb3146ccc969b4d466 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Fri, 23 Mar 2012 15:01:52 -0700 Subject: [PATCH] consolidate WARN_...ONCE() static variables Due to the alignment of following variables, these typically consume more than just the single byte that 'bool' requires, and as there are a few hundred instances, the cache pollution (not so much the waste of memory) sums up. Put these variables into their own section, outside of any half way frequently used memory range. Do the same also to the __warned variable of rcu_lockdep_assert(). (Don't, however, include the ones used by printk_once() and alike, as they can potentially be hot.) Signed-off-by: Jan Beulich Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-generic/bug.h | 6 +++--- include/asm-generic/vmlinux.lds.h | 1 + include/linux/rcupdate.h | 2 +- 3 files changed, 5 insertions(+), 4 deletions(-) diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h index 84458b0..2520a6e 100644 --- a/include/asm-generic/bug.h +++ b/include/asm-generic/bug.h @@ -134,7 +134,7 @@ extern void warn_slowpath_null(const char *file, const int line); #endif #define WARN_ON_ONCE(condition) ({ \ - static bool __warned; \ + static bool __section(.data.unlikely) __warned; \ int __ret_warn_once = !!(condition); \ \ if (unlikely(__ret_warn_once)) \ @@ -144,7 +144,7 @@ extern void warn_slowpath_null(const char *file, const int line); }) #define WARN_ONCE(condition, format...) ({ \ - static bool __warned; \ + static bool __section(.data.unlikely) __warned; \ int __ret_warn_once = !!(condition); \ \ if (unlikely(__ret_warn_once)) \ @@ -154,7 +154,7 @@ extern void warn_slowpath_null(const char *file, const int line); }) #define WARN_TAINT_ONCE(condition, taint, format...) ({ \ - static bool __warned; \ + static bool __section(.data.unlikely) __warned; \ int __ret_warn_once = !!(condition); \ \ if (unlikely(__ret_warn_once)) \ diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index b5e2e4c..798603e 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -167,6 +167,7 @@ CPU_KEEP(exit.data) \ MEM_KEEP(init.data) \ MEM_KEEP(exit.data) \ + *(.data.unlikely) \ STRUCT_ALIGN(); \ *(__tracepoints) \ /* implement dynamic printk debug */ \ diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 9372174..2c62594 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -418,7 +418,7 @@ extern int rcu_my_thread_group_empty(void); */ #define rcu_lockdep_assert(c, s) \ do { \ - static bool __warned; \ + static bool __section(.data.unlikely) __warned; \ if (debug_lockdep_rcu_enabled() && !__warned && !(c)) { \ __warned = true; \ lockdep_rcu_suspicious(__FILE__, __LINE__, s); \ -- 2.7.4