From: Zi Yan <zi....@cs.rutgers.edu>

From: Zi Yan <z...@nvidia.com>

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 <z...@nvidia.com>
Signed-off-by: Zi Yan <zi....@cs.rutgers.edu>
---
 kernel/sysctl.c | 11 +++++++++++
 mm/migrate.c    |  6 ++++++
 2 files changed, 17 insertions(+)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index d54ce12..6c79444 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -98,6 +98,8 @@
 #if defined(CONFIG_SYSCTL)
 
 
+extern int accel_page_copy;
+
 /* External variables not in a header file. */
 extern int suid_dumpable;
 #ifdef CONFIG_COREDUMP
@@ -1361,6 +1363,15 @@ static struct ctl_table vm_table[] = {
                .proc_handler   = &hugetlb_mempolicy_sysctl_handler,
        },
 #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 244ece6..e64b490 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -48,6 +48,8 @@
 
 #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
@@ -651,6 +653,10 @@ 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_mt(dst, src, nr_pages);
 
-- 
2.10.2

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