From: Zi Yan <ziy@xxxxxxxxxx>
Since base page migration did not gain any speedup from
multi-threaded methods, we only accelerate the huge page case.
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
---
kernel/sysctl.c | 11 +++++++++++
mm/migrate.c | 6 ++++++
2 files changed, 17 insertions(+)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index e5da394..3d8490e 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -101,6 +101,8 @@
#if defined(CONFIG_SYSCTL)
+extern int accel_page_copy;
+
/* External variables not in a header file. */
extern int suid_dumpable;
#ifdef CONFIG_COREDUMP
@@ -1430,6 +1432,15 @@ static struct ctl_table vm_table[] = {
.extra2 = &one,
},
#endif
+ {
+ .procname = "accel_page_copy",
+ .data = &accel_page_copy,
+ .maxlen = sizeof(accel_page_copy),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
{
.procname = "hugetlb_shm_group",
.data = &sysctl_hugetlb_shm_group,
diff --git a/mm/migrate.c b/mm/migrate.c
index dd6ccbe..8a344e2 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -55,6 +55,8 @@
#include "internal.h"
+int accel_page_copy = 1;
+
/*
* migrate_prep() needs to be called before we start compiling a list of pages
* to be migrated using isolate_lru_page(). If scheduling work on other CPUs is
@@ -589,6 +591,10 @@ static void copy_huge_page(struct page *dst, struct page *src,
nr_pages = hpage_nr_pages(src);
}
+ /* Try to accelerate page migration if it is not specified in mode */
+ if (accel_page_copy)
+ mode |= MIGRATE_MT;
+
if (mode & MIGRATE_MT)
rc = copy_page_multithread(dst, src, nr_pages);
--
2.7.4
