[PATCH 6/6] sysctl: Add global tunable mt_page_copy
From: Anshuman Khandual <hidden>
Date: 2017-02-17 11:27:16
Also in:
lkml
Subsystem:
memory management, memory management - memory policy and migration, proc sysctl, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Kees Cook, Joel Granados, Linus Torvalds
From: Zi Yan <ziy@nvidia.com> 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 <redacted> Signed-off-by: Anshuman Khandual <redacted> --- kernel/sysctl.c | 10 ++++++++++ mm/migrate.c | 14 ++++++++++++++ 2 files changed, 24 insertions(+)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 1aea594..e5f7ca9 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c@@ -98,6 +98,7 @@ #if defined(CONFIG_SYSCTL) /* External variables not in a header file. */ +extern int mt_page_copy; extern int suid_dumpable; #ifdef CONFIG_COREDUMP extern int core_uses_pid;
@@ -1346,6 +1347,15 @@ 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 660c4b2..75b6d7a 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c@@ -48,6 +48,8 @@ #include "internal.h" +int mt_page_copy; + /* * 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
@@ -611,6 +613,9 @@ 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);
@@ -629,6 +634,9 @@ void migrate_page_copy(struct page *newpage, struct page *page, { int cpupid; + if (mt_page_copy) + mode |= MIGRATE_MT; + if (PageHuge(page) || PageTransHuge(page)) { copy_huge_page(newpage, page, mode); } else {
@@ -695,6 +703,12 @@ void migrate_page_copy(struct page *newpage, struct page *page, } EXPORT_SYMBOL(migrate_page_copy); +static int __init mt_page_copy_init(void) +{ + mt_page_copy = 0; + return 0; +} +subsys_initcall(mt_page_copy_init); /************************************************************ * Migration functions ***********************************************************/
--
2.9.3
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