From: Zi Yan <ziy@xxxxxxxxxx>
A new global sysctl tunable 'mt_page_copy' is added which will override
syscall specific requests and enable multi threaded page copy during
all migrations on the system. This tunable is disabled by default.
Signed-off-by: Zi Yan <zi.yan@xxxxxxxxxxxxxx>
Signed-off-by: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
---
kernel/sysctl.c | 11 +++++++++++
mm/migrate.c | 5 +++++
2 files changed, 16 insertions(+)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 5b8c0fb3f0ea..70a654146519 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -97,6 +97,8 @@
#if defined(CONFIG_SYSCTL)
+extern int mt_page_copy;
+
/* External variables not in a header file. */
extern int suid_dumpable;
#ifdef CONFIG_COREDUMP
@@ -1360,6 +1362,15 @@ static struct ctl_table vm_table[] = {
.proc_handler = &hugetlb_mempolicy_sysctl_handler,
},
#endif
+ {
+ .procname = "mt_page_copy",
+ .data = &mt_page_copy,
+ .maxlen = sizeof(mt_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 2e58aad7c96f..0e9b1f17cf8b 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -48,6 +48,8 @@
#include "internal.h"
+int mt_page_copy = 0;
+
/*
* 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
@@ -618,6 +620,9 @@ static void copy_huge_page(struct page *dst, struct page *src,
nr_pages = hpage_nr_pages(src);
}
+ if (mt_page_copy)
+ mode |= MIGRATE_MT;
+
if (mode & MIGRATE_MT)
rc = copy_pages_mthread(dst, src, nr_pages);
--
2.11.0
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