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authorShaohua Li <shaohua.li@intel.com>2010-10-20 11:07:02 +0800
committerH. Peter Anvin <hpa@linux.intel.com>2010-10-20 14:33:58 -0700
commitc957ef2c59e952803766ddc22e89981ab534606f (patch)
tree3add0b22291af02c8675206861327f8314638bb9 /include
parentf01f7c56a1425b9749a99af821e1de334fb64d7e (diff)
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percpu: Introduce a read-mostly percpu API
Add a new readmostly percpu section and API. This can be used to avoid dirtying data lines which are generally not written to, which is especially important for data which may be accessed by processors other than the one for which the percpu area belongs to. [ hpa: moved it *after* the page-aligned section, for obvious reasons. ] Signed-off-by: Shaohua Li <shaohua.li@intel.com> LKML-Reference: <1287544022.4571.7.camel@sli10-conroe.sh.intel.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'include')
-rw-r--r--include/asm-generic/vmlinux.lds.h4
-rw-r--r--include/linux/percpu-defs.h9
2 files changed, 13 insertions, 0 deletions
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 8a92a170fb7..d7e7b21511b 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -677,7 +677,9 @@
- LOAD_OFFSET) { \
VMLINUX_SYMBOL(__per_cpu_start) = .; \
*(.data..percpu..first) \
+ . = ALIGN(PAGE_SIZE); \
*(.data..percpu..page_aligned) \
+ *(.data..percpu..readmostly) \
*(.data..percpu) \
*(.data..percpu..shared_aligned) \
VMLINUX_SYMBOL(__per_cpu_end) = .; \
@@ -703,6 +705,8 @@
VMLINUX_SYMBOL(__per_cpu_load) = .; \
VMLINUX_SYMBOL(__per_cpu_start) = .; \
*(.data..percpu..first) \
+ . = ALIGN(PAGE_SIZE); \
+ *(.data..percpu..readmostly) \
*(.data..percpu..page_aligned) \
*(.data..percpu) \
*(.data..percpu..shared_aligned) \
diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h
index ce2dc655cd1..27ef6b190ea 100644
--- a/include/linux/percpu-defs.h
+++ b/include/linux/percpu-defs.h
@@ -139,6 +139,15 @@
__aligned(PAGE_SIZE)
/*
+ * Declaration/definition used for per-CPU variables that must be read mostly.
+ */
+#define DECLARE_PER_CPU_READ_MOSTLY(type, name) \
+ DECLARE_PER_CPU_SECTION(type, name, "..readmostly")
+
+#define DEFINE_PER_CPU_READ_MOSTLY(type, name) \
+ DEFINE_PER_CPU_SECTION(type, name, "..readmostly")
+
+/*
* Intermodule exports for per-CPU variables. sparse forgets about
* address space across EXPORT_SYMBOL(), change EXPORT_SYMBOL() to
* noop if __CHECKER__.