[RFC v1 1/2] VS1544 KSM generic memory comparison functions

From: Claudio Imbrenda
Date: Mon Sep 25 2017 - 04:46:56 EST

This is just a refactoring of the existing code:

* Split the page checksum and page comparison functions from ksm.c into
a new asm-generic header (page_memops.h)

* Add a line in every Kbuild of every arch, to use the generic version
of page_memops.h

Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxxxxxxx>
---
arch/alpha/include/asm/Kbuild | 1 +
arch/arc/include/asm/Kbuild | 1 +
arch/arm/include/asm/Kbuild | 1 +
arch/arm64/include/asm/Kbuild | 1 +
arch/blackfin/include/asm/Kbuild | 1 +
arch/c6x/include/asm/Kbuild | 1 +
arch/cris/include/asm/Kbuild | 1 +
arch/frv/include/asm/Kbuild | 1 +
arch/h8300/include/asm/Kbuild | 1 +
arch/hexagon/include/asm/Kbuild | 1 +
arch/ia64/include/asm/Kbuild | 1 +
arch/m32r/include/asm/Kbuild | 1 +
arch/m68k/include/asm/Kbuild | 1 +
arch/metag/include/asm/Kbuild | 1 +
arch/microblaze/include/asm/Kbuild | 1 +
arch/mips/include/asm/Kbuild | 1 +
arch/mn10300/include/asm/Kbuild | 1 +
arch/nios2/include/asm/Kbuild | 1 +
arch/openrisc/include/asm/Kbuild | 1 +
arch/parisc/include/asm/Kbuild | 1 +
arch/powerpc/include/asm/Kbuild | 1 +
arch/s390/include/asm/Kbuild | 1 +
arch/score/include/asm/Kbuild | 1 +
arch/sh/include/asm/Kbuild | 1 +
arch/sparc/include/asm/Kbuild | 1 +
arch/tile/include/asm/Kbuild | 1 +
arch/um/include/asm/Kbuild | 1 +
arch/unicore32/include/asm/Kbuild | 1 +
arch/x86/include/asm/Kbuild | 1 +
arch/xtensa/include/asm/Kbuild | 1 +
include/asm-generic/page_memops.h | 31 +++++++++++++++++++++++++++++++
mm/ksm.c | 27 +++------------------------
32 files changed, 64 insertions(+), 24 deletions(-)
create mode 100644 include/asm-generic/page_memops.h

diff --git a/arch/alpha/include/asm/Kbuild b/arch/alpha/include/asm/Kbuild
index d103db5..ad3bbfd 100644
--- a/arch/alpha/include/asm/Kbuild
+++ b/arch/alpha/include/asm/Kbuild
@@ -6,6 +6,7 @@ generic-y += export.h
generic-y += irq_work.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += preempt.h
generic-y += sections.h
generic-y += trace_clock.h
diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild
index 353dae3..7039177 100644
--- a/arch/arc/include/asm/Kbuild
+++ b/arch/arc/include/asm/Kbuild
@@ -16,6 +16,7 @@ generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += msi.h
+generic-y += page_memops.h
generic-y += parport.h
generic-y += pci.h
generic-y += percpu.h
diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild
index 721ab5e..ce1c939 100644
--- a/arch/arm/include/asm/Kbuild
+++ b/arch/arm/include/asm/Kbuild
@@ -10,6 +10,7 @@ generic-y += local.h
generic-y += local64.h
generic-y += mm-arch-hooks.h
generic-y += msi.h
+generic-y += page_memops.h
generic-y += parport.h
generic-y += preempt.h
generic-y += rwsem.h
diff --git a/arch/arm64/include/asm/Kbuild b/arch/arm64/include/asm/Kbuild
index f81c7b6..c6070f3 100644
--- a/arch/arm64/include/asm/Kbuild
+++ b/arch/arm64/include/asm/Kbuild
@@ -15,6 +15,7 @@ generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += msi.h
+generic-y += page_memops.h
generic-y += preempt.h
generic-y += rwsem.h
generic-y += segment.h
diff --git a/arch/blackfin/include/asm/Kbuild b/arch/blackfin/include/asm/Kbuild
index fe73697..c450957 100644
--- a/arch/blackfin/include/asm/Kbuild
+++ b/arch/blackfin/include/asm/Kbuild
@@ -16,6 +16,7 @@ generic-y += local.h
generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += percpu.h
generic-y += pgalloc.h
generic-y += preempt.h
diff --git a/arch/c6x/include/asm/Kbuild b/arch/c6x/include/asm/Kbuild
index d717329..69e46f6 100644
--- a/arch/c6x/include/asm/Kbuild
+++ b/arch/c6x/include/asm/Kbuild
@@ -23,6 +23,7 @@ generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += mmu.h
generic-y += mmu_context.h
+generic-y += page_memops.h
generic-y += pci.h
generic-y += percpu.h
generic-y += pgalloc.h
diff --git a/arch/cris/include/asm/Kbuild b/arch/cris/include/asm/Kbuild
index 460349c..4d274ad 100644
--- a/arch/cris/include/asm/Kbuild
+++ b/arch/cris/include/asm/Kbuild
@@ -21,6 +21,7 @@ generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += module.h
+generic-y += page_memops.h
generic-y += percpu.h
generic-y += preempt.h
generic-y += sections.h
diff --git a/arch/frv/include/asm/Kbuild b/arch/frv/include/asm/Kbuild
index 2cf7648..c767527 100644
--- a/arch/frv/include/asm/Kbuild
+++ b/arch/frv/include/asm/Kbuild
@@ -7,6 +7,7 @@ generic-y += fb.h
generic-y += irq_work.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += preempt.h
generic-y += trace_clock.h
generic-y += word-at-a-time.h
diff --git a/arch/h8300/include/asm/Kbuild b/arch/h8300/include/asm/Kbuild
index bc07749..f877554 100644
--- a/arch/h8300/include/asm/Kbuild
+++ b/arch/h8300/include/asm/Kbuild
@@ -31,6 +31,7 @@ generic-y += mm-arch-hooks.h
generic-y += mmu.h
generic-y += mmu_context.h
generic-y += module.h
+generic-y += page_memops.h
generic-y += parport.h
generic-y += percpu.h
generic-y += pgalloc.h
diff --git a/arch/hexagon/include/asm/Kbuild b/arch/hexagon/include/asm/Kbuild
index 3401368..75a8ae4 100644
--- a/arch/hexagon/include/asm/Kbuild
+++ b/arch/hexagon/include/asm/Kbuild
@@ -21,6 +21,7 @@ generic-y += local.h
generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += pci.h
generic-y += percpu.h
generic-y += preempt.h
diff --git a/arch/ia64/include/asm/Kbuild b/arch/ia64/include/asm/Kbuild
index 1d7641f..5c28f3a 100644
--- a/arch/ia64/include/asm/Kbuild
+++ b/arch/ia64/include/asm/Kbuild
@@ -3,6 +3,7 @@ generic-y += exec.h
generic-y += irq_work.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += preempt.h
generic-y += trace_clock.h
generic-y += vtime.h
diff --git a/arch/m32r/include/asm/Kbuild b/arch/m32r/include/asm/Kbuild
index 7e11b12..07096a2 100644
--- a/arch/m32r/include/asm/Kbuild
+++ b/arch/m32r/include/asm/Kbuild
@@ -7,6 +7,7 @@ generic-y += kprobes.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += module.h
+generic-y += page_memops.h
generic-y += preempt.h
generic-y += sections.h
generic-y += trace_clock.h
diff --git a/arch/m68k/include/asm/Kbuild b/arch/m68k/include/asm/Kbuild
index 59d6d0d..73b48b4 100644
--- a/arch/m68k/include/asm/Kbuild
+++ b/arch/m68k/include/asm/Kbuild
@@ -15,6 +15,7 @@ generic-y += local.h
generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += percpu.h
generic-y += preempt.h
generic-y += sections.h
diff --git a/arch/metag/include/asm/Kbuild b/arch/metag/include/asm/Kbuild
index 3fba97e..9d33550 100644
--- a/arch/metag/include/asm/Kbuild
+++ b/arch/metag/include/asm/Kbuild
@@ -19,6 +19,7 @@ generic-y += local.h
generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += pci.h
generic-y += percpu.h
generic-y += preempt.h
diff --git a/arch/microblaze/include/asm/Kbuild b/arch/microblaze/include/asm/Kbuild
index 9d66f77..34bd980 100644
--- a/arch/microblaze/include/asm/Kbuild
+++ b/arch/microblaze/include/asm/Kbuild
@@ -20,6 +20,7 @@ generic-y += local.h
generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += parport.h
generic-y += percpu.h
generic-y += preempt.h
diff --git a/arch/mips/include/asm/Kbuild b/arch/mips/include/asm/Kbuild
index 7c8aab2..119854c8 100644
--- a/arch/mips/include/asm/Kbuild
+++ b/arch/mips/include/asm/Kbuild
@@ -9,6 +9,7 @@ generic-y += irq_work.h
generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += parport.h
generic-y += percpu.h
generic-y += preempt.h
diff --git a/arch/mn10300/include/asm/Kbuild b/arch/mn10300/include/asm/Kbuild
index db5b578..302d58f 100644
--- a/arch/mn10300/include/asm/Kbuild
+++ b/arch/mn10300/include/asm/Kbuild
@@ -8,6 +8,7 @@ generic-y += fb.h
generic-y += irq_work.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += preempt.h
generic-y += sections.h
generic-y += trace_clock.h
diff --git a/arch/nios2/include/asm/Kbuild b/arch/nios2/include/asm/Kbuild
index 896c26a..819ae2c 100644
--- a/arch/nios2/include/asm/Kbuild
+++ b/arch/nios2/include/asm/Kbuild
@@ -26,6 +26,7 @@ generic-y += local.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += module.h
+generic-y += page_memops.h
generic-y += pci.h
generic-y += percpu.h
generic-y += preempt.h
diff --git a/arch/openrisc/include/asm/Kbuild b/arch/openrisc/include/asm/Kbuild
index 5bea416..f123dd3 100644
--- a/arch/openrisc/include/asm/Kbuild
+++ b/arch/openrisc/include/asm/Kbuild
@@ -25,6 +25,7 @@ generic-y += local.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += module.h
+generic-y += page_memops.h
generic-y += pci.h
generic-y += percpu.h
generic-y += preempt.h
diff --git a/arch/parisc/include/asm/Kbuild b/arch/parisc/include/asm/Kbuild
index a411395..875c2c2 100644
--- a/arch/parisc/include/asm/Kbuild
+++ b/arch/parisc/include/asm/Kbuild
@@ -14,6 +14,7 @@ generic-y += local.h
generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += percpu.h
generic-y += preempt.h
generic-y += seccomp.h
diff --git a/arch/powerpc/include/asm/Kbuild b/arch/powerpc/include/asm/Kbuild
index 5c4fbc8..66f5c0b 100644
--- a/arch/powerpc/include/asm/Kbuild
+++ b/arch/powerpc/include/asm/Kbuild
@@ -5,6 +5,7 @@ generic-y += irq_regs.h
generic-y += irq_work.h
generic-y += local64.h
generic-y += mcs_spinlock.h
+generic-y += page_memops.h
generic-y += preempt.h
generic-y += rwsem.h
generic-y += vtime.h
diff --git a/arch/s390/include/asm/Kbuild b/arch/s390/include/asm/Kbuild
index b3c8847..e68b429 100644
--- a/arch/s390/include/asm/Kbuild
+++ b/arch/s390/include/asm/Kbuild
@@ -14,6 +14,7 @@ generic-y += local.h
generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += preempt.h
generic-y += trace_clock.h
generic-y += word-at-a-time.h
diff --git a/arch/score/include/asm/Kbuild b/arch/score/include/asm/Kbuild
index 54b3b20..ea172d3 100644
--- a/arch/score/include/asm/Kbuild
+++ b/arch/score/include/asm/Kbuild
@@ -5,6 +5,7 @@ generic-y += extable.h
generic-y += irq_work.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += preempt.h
generic-y += sections.h
generic-y += trace_clock.h
diff --git a/arch/sh/include/asm/Kbuild b/arch/sh/include/asm/Kbuild
index 1a6f9c3..10fd909 100644
--- a/arch/sh/include/asm/Kbuild
+++ b/arch/sh/include/asm/Kbuild
@@ -10,6 +10,7 @@ generic-y += local.h
generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += parport.h
generic-y += percpu.h
generic-y += preempt.h
diff --git a/arch/sparc/include/asm/Kbuild b/arch/sparc/include/asm/Kbuild
index 80ddc01..17817e5 100644
--- a/arch/sparc/include/asm/Kbuild
+++ b/arch/sparc/include/asm/Kbuild
@@ -14,6 +14,7 @@ generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += module.h
+generic-y += page_memops.h
generic-y += preempt.h
generic-y += rwsem.h
generic-y += serial.h
diff --git a/arch/tile/include/asm/Kbuild b/arch/tile/include/asm/Kbuild
index d28d2b8..6e6da6c 100644
--- a/arch/tile/include/asm/Kbuild
+++ b/arch/tile/include/asm/Kbuild
@@ -11,6 +11,7 @@ generic-y += local.h
generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += parport.h
generic-y += preempt.h
generic-y += seccomp.h
diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild
index 50a32c3..fcb3f70 100644
--- a/arch/um/include/asm/Kbuild
+++ b/arch/um/include/asm/Kbuild
@@ -17,6 +17,7 @@ generic-y += irq_work.h
generic-y += kdebug.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += param.h
generic-y += pci.h
generic-y += percpu.h
diff --git a/arch/unicore32/include/asm/Kbuild b/arch/unicore32/include/asm/Kbuild
index fda7e21..4908550 100644
--- a/arch/unicore32/include/asm/Kbuild
+++ b/arch/unicore32/include/asm/Kbuild
@@ -21,6 +21,7 @@ generic-y += local.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
generic-y += module.h
+generic-y += page_memops.h
generic-y += parport.h
generic-y += percpu.h
generic-y += preempt.h
diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild
index 5d6a53f..669409d30 100644
--- a/arch/x86/include/asm/Kbuild
+++ b/arch/x86/include/asm/Kbuild
@@ -11,3 +11,4 @@ generic-y += dma-contiguous.h
generic-y += early_ioremap.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
diff --git a/arch/xtensa/include/asm/Kbuild b/arch/xtensa/include/asm/Kbuild
index dff7cc3..1b97064 100644
--- a/arch/xtensa/include/asm/Kbuild
+++ b/arch/xtensa/include/asm/Kbuild
@@ -18,6 +18,7 @@ generic-y += local.h
generic-y += local64.h
generic-y += mcs_spinlock.h
generic-y += mm-arch-hooks.h
+generic-y += page_memops.h
generic-y += param.h
generic-y += percpu.h
generic-y += preempt.h
diff --git a/include/asm-generic/page_memops.h b/include/asm-generic/page_memops.h
new file mode 100644
index 0000000..fd14160
--- /dev/null
+++ b/include/asm-generic/page_memops.h
@@ -0,0 +1,31 @@
+#ifndef _ASM_GENERIC_PAGE_MEMOPS_H
+#define _ASM_GENERIC_PAGE_MEMOPS_H
+
+#include <linux/mm_types.h>
+#include <linux/highmem.h>
+#include <linux/jhash.h>
+
+static inline u32 calc_page_checksum(struct page *page)
+{
+ void *addr = kmap_atomic(page);
+ u32 checksum;
+
+ checksum = jhash2(addr, PAGE_SIZE / 4, 17);
+ kunmap_atomic(addr);
+ return checksum;
+}
+
+static inline int memcmp_pages(struct page *page1, struct page *page2)
+{
+ char *addr1, *addr2;
+ int ret;
+
+ addr1 = kmap_atomic(page1);
+ addr2 = kmap_atomic(page2);
+ ret = memcmp(addr1, addr2, PAGE_SIZE);
+ kunmap_atomic(addr2);
+ kunmap_atomic(addr1);
+ return ret;
+}
+
+#endif
diff --git a/mm/ksm.c b/mm/ksm.c
index db20f84..3de568c 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -41,6 +41,7 @@
#include <linux/numa.h>

#include <asm/tlbflush.h>
+#include <asm/page_memops.h>
#include "internal.h"

#ifdef CONFIG_NUMA
@@ -982,28 +983,6 @@ static int unmerge_and_remove_all_rmap_items(void)
}
#endif /* CONFIG_SYSFS */

-static u32 calc_checksum(struct page *page)
-{
- u32 checksum;
- void *addr = kmap_atomic(page);
- checksum = jhash2(addr, PAGE_SIZE / 4, 17);
- kunmap_atomic(addr);
- return checksum;
-}
-
-static int memcmp_pages(struct page *page1, struct page *page2)
-{
- char *addr1, *addr2;
- int ret;
-
- addr1 = kmap_atomic(page1);
- addr2 = kmap_atomic(page2);
- ret = memcmp(addr1, addr2, PAGE_SIZE);
- kunmap_atomic(addr2);
- kunmap_atomic(addr1);
- return ret;
-}
-
static inline int pages_identical(struct page *page1, struct page *page2)
{
return !memcmp_pages(page1, page2);
@@ -2049,7 +2028,7 @@ static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item)
* don't want to insert it in the unstable tree, and we don't want
* to waste our time searching for something identical to it there.
*/
- checksum = calc_checksum(page);
+ checksum = calc_page_checksum(page);
if (rmap_item->oldchecksum != checksum) {
rmap_item->oldchecksum = checksum;
return;
@@ -3055,7 +3034,7 @@ static int __init ksm_init(void)
int err;

/* The correct value depends on page size and endianness */
- zero_checksum = calc_checksum(ZERO_PAGE(0));
+ zero_checksum = calc_page_checksum(ZERO_PAGE(0));
/* Default to false for backwards compatibility */
ksm_use_zero_pages = false;

--
2.7.4