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Date: Fri, 17 Feb 2017 16:54:53 +0530 From: Anshuman Khandual <khandual@...ux.vnet.ibm.com> To: linux-kernel@...r.kernel.org, linux-mm@...ck.org Cc: mhocko@...e.com, vbabka@...e.cz, mgorman@...e.de, minchan@...nel.org, aneesh.kumar@...ux.vnet.ibm.com, bsingharora@...il.com, srikar@...ux.vnet.ibm.com, haren@...ux.vnet.ibm.com, jglisse@...hat.com, dave.hansen@...el.com, dan.j.williams@...el.com, zi.yan@...rutgers.edu Subject: [PATCH 6/6] sysctl: Add global tunable mt_page_copy From: Zi Yan <ziy@...dia.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 <zi.yan@...rutgers.edu> Signed-off-by: Anshuman Khandual <khandual@...ux.vnet.ibm.com> --- 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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