The patch titled
Subject: mm, vmacache: hash addresses based on pmd fix
has been added to the -mm tree. Its filename is
mm-vmacache-hash-addresses-based-on-pmd-fix.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-vmacache-hash-addresses-based-on-pmd-fix.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-vmacache-hash-addresses-based-on-pmd-fix.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: David Rientjes <rientjes@xxxxxxxxxx>
Subject: mm, vmacache: hash addresses based on pmd fix
- use PMD_SHIFT only if CONFIG_MMU is used, otherwise there is only
pgdir, per kbuild test robot
- fix vmacache_find_exact() for correct formal name, per me
- only check vma->vm_mm == mm for CONFIG_DEBUG_VM_VMACACHE, per akpm
Tested for {allnoconfig, defconfig} on alpha, arc, arm, arm64, c6x, h8300,
i386, ia64, m68k, microblaze, mips, mips, nds32, nios2, parisc, powerpc,
riscv, s390, sh, sparc, um, and xtensa.
Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1807231532290.109445@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Reported-by: kbuild test robot <lkp@xxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmacache.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff -puN mm/vmacache.c~mm-vmacache-hash-addresses-based-on-pmd-fix mm/vmacache.c
--- a/mm/vmacache.c~mm-vmacache-hash-addresses-based-on-pmd-fix
+++ a/mm/vmacache.c
@@ -6,12 +6,18 @@
#include <linux/sched/task.h>
#include <linux/mm.h>
#include <linux/vmacache.h>
+#include <asm/pgtable.h>
/*
- * Hash based on the pmd of addr. Provides a good hit rate for workloads with
- * spatial locality.
+ * Hash based on the pmd of addr if configured with MMU, which provides a good
+ * hit rate for workloads with spatial locality. Otherwise, use pages.
*/
-#define VMACACHE_HASH(addr) ((addr >> PMD_SHIFT) & VMACACHE_MASK)
+#ifdef CONFIG_MMU
+#define VMACACHE_SHIFT PMD_SHIFT
+#else
+#define VMACACHE_SHIFT PAGE_SHIFT
+#endif
+#define VMACACHE_HASH(addr) ((addr >> VMACACHE_SHIFT) & VMACACHE_MASK)
/*
* Flush vma caches for threads that share a given mm.
@@ -105,8 +111,10 @@ struct vm_area_struct *vmacache_find(str
struct vm_area_struct *vma = current->vmacache.vmas[idx];
if (vma) {
+#ifdef CONFIG_DEBUG_VM_VMACACHE
if (WARN_ON_ONCE(vma->vm_mm != mm))
break;
+#endif
if (vma->vm_start <= addr && vma->vm_end > addr) {
count_vm_vmacache_event(VMACACHE_FIND_HITS);
return vma;
@@ -124,7 +132,7 @@ struct vm_area_struct *vmacache_find_exa
unsigned long start,
unsigned long end)
{
- int idx = VMACACHE_HASH(addr);
+ int idx = VMACACHE_HASH(start);
int i;
count_vm_vmacache_event(VMACACHE_FIND_CALLS);
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
mm-vmacache-hash-addresses-based-on-pmd.patch
mm-vmacache-hash-addresses-based-on-pmd-fix.patch
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