[RFC PATCH 04/14] mm/migrate: Add new migrate mode MIGRATE_MT
From: Zi Yan <hidden>
Date: 2017-02-17 15:06:09
Subsystem:
memory management, memory management - memory policy and migration, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
From: Zi Yan <ziy@nvidia.com> This change adds a new migration mode called MIGRATE_MT to enable multi threaded page copy implementation inside copy_huge_page() function by selectively calling copy_pages_mthread() when requested. But it still falls back using the regular page copy mechanism instead the previous multi threaded attempt fails. It also attempts multi threaded copy for regular pages. Signed-off-by: Zi Yan <redacted> Signed-off-by: Anshuman Khandual <redacted> --- include/linux/migrate_mode.h | 1 + mm/migrate.c | 25 ++++++++++++++++++------- 2 files changed, 19 insertions(+), 7 deletions(-)
diff --git a/include/linux/migrate_mode.h b/include/linux/migrate_mode.h
index 89c170060e5b..d344ad60f499 100644
--- a/include/linux/migrate_mode.h
+++ b/include/linux/migrate_mode.h@@ -12,6 +12,7 @@ enum migrate_mode { MIGRATE_SYNC_LIGHT = 1<<1, MIGRATE_SYNC = 1<<2, MIGRATE_ST = 1<<3, + MIGRATE_MT = 1<<4, }; #endif /* MIGRATE_MODE_H_INCLUDED */
diff --git a/mm/migrate.c b/mm/migrate.c
index 87253cb9b50a..21307219428d 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c@@ -601,6 +601,7 @@ static void copy_huge_page(struct page *dst, struct page *src, { int i; int nr_pages; + int rc = -EFAULT; if (PageHuge(src)) { /* hugetlbfs page */
@@ -617,10 +618,14 @@ static void copy_huge_page(struct page *dst, struct page *src, nr_pages = hpage_nr_pages(src); } - for (i = 0; i < nr_pages; i++) { - cond_resched(); - copy_highpage(dst + i, src + i); - } + if (mode & MIGRATE_MT) + rc = copy_pages_mthread(dst, src, nr_pages); + + if (rc) + for (i = 0; i < nr_pages; i++) { + cond_resched(); + copy_highpage(dst + i, src + i); + } } /*
@@ -631,10 +636,16 @@ void migrate_page_copy(struct page *newpage, struct page *page, { int cpupid; - if (PageHuge(page) || PageTransHuge(page)) + if (PageHuge(page) || PageTransHuge(page)) { copy_huge_page(newpage, page, mode); - else - copy_highpage(newpage, page); + } else { + if (mode & MIGRATE_MT) { + if (copy_pages_mthread(newpage, page, 1)) + copy_highpage(newpage, page); + } else { + copy_highpage(newpage, page); + } + } if (PageError(page)) SetPageError(newpage);
--
2.11.0
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