Messages in this thread Patch in this message | | | From | Zi Yan <> | Subject | [RFC PATCH 02/31] mm: migrate: Add THP exchange support. | Date | Fri, 15 Feb 2019 14:08:27 -0800 |
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From: Zi Yan <ziy@nvidia.com>
Add support for exchange between two THPs.
Signed-off-by: Zi Yan <ziy@nvidia.com> --- mm/exchange.c | 47 ++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 38 insertions(+), 9 deletions(-)
diff --git a/mm/exchange.c b/mm/exchange.c index a607348cc6f4..8cf286fc0f10 100644 --- a/mm/exchange.c +++ b/mm/exchange.c @@ -48,7 +48,8 @@ struct page_flags { unsigned int page_swapcache:1; unsigned int page_writeback:1; unsigned int page_private:1; - unsigned int __pad:3; + unsigned int page_doublemap:1; + unsigned int __pad:2; }; @@ -125,20 +126,23 @@ static void exchange_huge_page(struct page *dst, struct page *src) static void exchange_page_flags(struct page *to_page, struct page *from_page) { int from_cpupid, to_cpupid; - struct page_flags from_page_flags, to_page_flags; + struct page_flags from_page_flags = {0}, to_page_flags = {0}; struct mem_cgroup *to_memcg = page_memcg(to_page), *from_memcg = page_memcg(from_page); from_cpupid = page_cpupid_xchg_last(from_page, -1); - from_page_flags.page_error = TestClearPageError(from_page); + from_page_flags.page_error = PageError(from_page); + if (from_page_flags.page_error) + ClearPageError(from_page); from_page_flags.page_referenced = TestClearPageReferenced(from_page); from_page_flags.page_uptodate = PageUptodate(from_page); ClearPageUptodate(from_page); from_page_flags.page_active = TestClearPageActive(from_page); from_page_flags.page_unevictable = TestClearPageUnevictable(from_page); from_page_flags.page_checked = PageChecked(from_page); - ClearPageChecked(from_page); + if (from_page_flags.page_checked) + ClearPageChecked(from_page); from_page_flags.page_mappedtodisk = PageMappedToDisk(from_page); ClearPageMappedToDisk(from_page); from_page_flags.page_dirty = PageDirty(from_page); @@ -148,18 +152,22 @@ static void exchange_page_flags(struct page *to_page, struct page *from_page) clear_page_idle(from_page); from_page_flags.page_swapcache = PageSwapCache(from_page); from_page_flags.page_writeback = test_clear_page_writeback(from_page); + from_page_flags.page_doublemap = PageDoubleMap(from_page); to_cpupid = page_cpupid_xchg_last(to_page, -1); - to_page_flags.page_error = TestClearPageError(to_page); + to_page_flags.page_error = PageError(to_page); + if (to_page_flags.page_error) + ClearPageError(to_page); to_page_flags.page_referenced = TestClearPageReferenced(to_page); to_page_flags.page_uptodate = PageUptodate(to_page); ClearPageUptodate(to_page); to_page_flags.page_active = TestClearPageActive(to_page); to_page_flags.page_unevictable = TestClearPageUnevictable(to_page); to_page_flags.page_checked = PageChecked(to_page); - ClearPageChecked(to_page); + if (to_page_flags.page_checked) + ClearPageChecked(to_page); to_page_flags.page_mappedtodisk = PageMappedToDisk(to_page); ClearPageMappedToDisk(to_page); to_page_flags.page_dirty = PageDirty(to_page); @@ -169,6 +177,7 @@ static void exchange_page_flags(struct page *to_page, struct page *from_page) clear_page_idle(to_page); to_page_flags.page_swapcache = PageSwapCache(to_page); to_page_flags.page_writeback = test_clear_page_writeback(to_page); + to_page_flags.page_doublemap = PageDoubleMap(to_page); /* set to_page */ if (from_page_flags.page_error) @@ -195,6 +204,8 @@ static void exchange_page_flags(struct page *to_page, struct page *from_page) set_page_young(to_page); if (from_page_flags.page_is_idle) set_page_idle(to_page); + if (from_page_flags.page_doublemap) + SetPageDoubleMap(to_page); /* set from_page */ if (to_page_flags.page_error) @@ -221,6 +232,8 @@ static void exchange_page_flags(struct page *to_page, struct page *from_page) set_page_young(from_page); if (to_page_flags.page_is_idle) set_page_idle(from_page); + if (to_page_flags.page_doublemap) + SetPageDoubleMap(from_page); /* * Copy NUMA information to the new page, to prevent over-eager @@ -280,6 +293,7 @@ static int exchange_page_move_mapping(struct address_space *to_mapping, VM_BUG_ON_PAGE(to_mapping != page_mapping(to_page), to_page); VM_BUG_ON_PAGE(from_mapping != page_mapping(from_page), from_page); + VM_BUG_ON(PageCompound(from_page) != PageCompound(to_page)); if (!to_mapping) { /* Anonymous page without mapping */ @@ -600,7 +614,6 @@ static int unmap_and_exchange(struct page *from_page, to_mapping = to_page->mapping; from_index = from_page->index; to_index = to_page->index; - /* * Corner case handling: * 1. When a new swap-cache page is read into, it is added to the LRU @@ -691,6 +704,23 @@ static int unmap_and_exchange(struct page *from_page, return rc; } +static bool can_be_exchanged(struct page *from, struct page *to) +{ + if (PageCompound(from) != PageCompound(to)) + return false; + + if (PageHuge(from) != PageHuge(to)) + return false; + + if (PageHuge(from) || PageHuge(to)) + return false; + + if (compound_order(from) != compound_order(to)) + return false; + + return true; +} + /* * Exchange pages in the exchange_list * @@ -751,9 +781,8 @@ static int exchange_pages(struct list_head *exchange_list, continue; } - /* TODO: compound page not supported */ /* to_page can be file-backed page */ - if (PageCompound(from_page) || + if (!can_be_exchanged(from_page, to_page) || page_mapping(from_page) ) { ++failed; -- 2.20.1
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