The patch titled
Subject: mm: rearrange vm_area_struct for fewer cache misses
has been added to the -mm tree. Its filename is
mm-rearrange-vm_area_struct-for-fewer-cache-misses.patch
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------------------------------------------------------
From: Rik van Riel <riel@xxxxxxxxxxx>
Subject: mm: rearrange vm_area_struct for fewer cache misses
The kernel walks the VMA rbtree in various places, including the page
fault path. However, the vm_rb node spanned two cache lines, on 64 bit
systems with 64 byte cache lines (most x86 systems).
Rearrange vm_area_struct a little, so all the information we need to do a
VMA tree walk is in the first cache line.
Signed-off-by: Michel Lespinasse <walken@xxxxxxxxxx>
Signed-off-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Paul Mundt <lethal@xxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Chris Metcalf <cmetcalf@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm_types.h | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff -puN include/linux/mm_types.h~mm-rearrange-vm_area_struct-for-fewer-cache-misses include/linux/mm_types.h
--- a/include/linux/mm_types.h~mm-rearrange-vm_area_struct-for-fewer-cache-misses
+++ a/include/linux/mm_types.h
@@ -226,7 +226,8 @@ struct vm_region {
* library, the executable area etc).
*/
struct vm_area_struct {
- struct mm_struct * vm_mm; /* The address space we belong to. */
+ /* The first cache line has the info for VMA tree walking. */
+
unsigned long vm_start; /* Our start address within vm_mm. */
unsigned long vm_end; /* The first byte after our end address
within vm_mm. */
@@ -234,9 +235,6 @@ struct vm_area_struct {
/* linked list of VM areas per task, sorted by address */
struct vm_area_struct *vm_next, *vm_prev;
- pgprot_t vm_page_prot; /* Access permissions of this VMA. */
- unsigned long vm_flags; /* Flags, see mm.h. */
-
struct rb_node vm_rb;
/*
@@ -247,6 +245,12 @@ struct vm_area_struct {
*/
unsigned long rb_subtree_gap;
+ /* Second cache line starts here. */
+
+ struct mm_struct * vm_mm; /* The address space we belong to. */
+ pgprot_t vm_page_prot; /* Access permissions of this VMA. */
+ unsigned long vm_flags; /* Flags, see mm.h. */
+
/*
* For areas with an address space and backing store,
* linkage into the address_space->i_mmap interval tree, or
_
Patches currently in -mm which might be from riel@xxxxxxxxxxx are
mm-rearrange-vm_area_struct-for-fewer-cache-misses.patch
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