From: Zi Yan <ziy@xxxxxxxxxx>
1. Exclude file-backed base pages from exchanging.
2. Split THP in exchange pages if THP support is disabled.
3. if THP migration is supported, only exchange THPs.
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
---
mm/memory_manage.c | 173 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 173 insertions(+)
diff --git a/mm/memory_manage.c b/mm/memory_manage.c
index 8b76fcf..d3d07b7 100644
--- a/mm/memory_manage.c
+++ b/mm/memory_manage.c
@@ -7,6 +7,7 @@
#include <linux/mempolicy.h>
#include <linux/memcontrol.h>
#include <linux/migrate.h>
+#include <linux/exchange.h>
#include <linux/mm_inline.h>
#include <linux/nodemask.h>
#include <linux/rmap.h>
@@ -253,6 +254,147 @@ static int putback_overflow_pages(unsigned long max_nr_base_pages,
huge_page_list, nr_huge_pages);
}
+static int add_pages_to_exchange_list(struct list_head *from_pagelist,
+ struct list_head *to_pagelist, struct exchange_page_info *info_list,
+ struct list_head *exchange_list, unsigned long info_list_size)
+{
+ unsigned long info_list_index = 0;
+ LIST_HEAD(failed_from_list);
+ LIST_HEAD(failed_to_list);
+
+ while (!list_empty(from_pagelist) && !list_empty(to_pagelist)) {
+ struct page *from_page, *to_page;
+ struct exchange_page_info *one_pair = &info_list[info_list_index];
+ int rc;
+
+ from_page = list_first_entry_or_null(from_pagelist, struct page, lru);
+ to_page = list_first_entry_or_null(to_pagelist, struct page, lru);
+
+ if (!from_page || !to_page)
+ break;
+
+ if (!thp_migration_supported() && PageTransHuge(from_page)) {
+ lock_page(from_page);
+ rc = split_huge_page_to_list(from_page, &from_page->lru);
+ unlock_page(from_page);
+ if (rc) {
+ list_move(&from_page->lru, &failed_from_list);
+ continue;
+ }
+ }
+
+ if (!thp_migration_supported() && PageTransHuge(to_page)) {
+ lock_page(to_page);
+ rc = split_huge_page_to_list(to_page, &to_page->lru);
+ unlock_page(to_page);
+ if (rc) {
+ list_move(&to_page->lru, &failed_to_list);
+ continue;
+ }
+ }
+
+ if (hpage_nr_pages(from_page) != hpage_nr_pages(to_page)) {
+ if (!(hpage_nr_pages(from_page) == 1 && hpage_nr_pages(from_page) == HPAGE_PMD_NR)) {
+ list_del(&from_page->lru);
+ list_add(&from_page->lru, &failed_from_list);
+ }
+ if (!(hpage_nr_pages(to_page) == 1 && hpage_nr_pages(to_page) == HPAGE_PMD_NR)) {
+ list_del(&to_page->lru);
+ list_add(&to_page->lru, &failed_to_list);
+ }
+ continue;
+ }
+
+ /* Exclude file-backed pages, exchange it concurrently is not
+ * implemented yet. */
+ if (page_mapping(from_page)) {
+ list_del(&from_page->lru);
+ list_add(&from_page->lru, &failed_from_list);
+ continue;
+ }
+ if (page_mapping(to_page)) {
+ list_del(&to_page->lru);
+ list_add(&to_page->lru, &failed_to_list);
+ continue;
+ }
+
+ list_del(&from_page->lru);
+ list_del(&to_page->lru);
+
+ one_pair->from_page = from_page;
+ one_pair->to_page = to_page;
+
+ list_add_tail(&one_pair->list, exchange_list);
+
+ info_list_index++;
+ if (info_list_index >= info_list_size)
+ break;
+ }
+ list_splice(&failed_from_list, from_pagelist);
+ list_splice(&failed_to_list, to_pagelist);
+
+ return info_list_index;
+}
+
+static unsigned long exchange_pages_between_nodes(unsigned long nr_from_pages,
+ unsigned long nr_to_pages, struct list_head *from_page_list,
+ struct list_head *to_page_list, int batch_size,
+ bool huge_page, enum migrate_mode mode)
+{
+ struct exchange_page_info *info_list;
+ unsigned long info_list_size = min_t(unsigned long,
+ nr_from_pages, nr_to_pages) / (huge_page?HPAGE_PMD_NR:1);
+ unsigned long added_size = 0;
+ bool migrate_concur = mode & MIGRATE_CONCUR;
+ LIST_HEAD(exchange_list);
+
+ /* non concurrent does not need to split into batches */
+ if (!migrate_concur || batch_size <= 0)
+ batch_size = info_list_size;
+
+ /* prepare for huge page split */
+ if (!thp_migration_supported() && huge_page) {
+ batch_size = batch_size * HPAGE_PMD_NR;
+ info_list_size = info_list_size * HPAGE_PMD_NR;
+ }
+
+ info_list = kvzalloc(sizeof(struct exchange_page_info)*batch_size,
+ GFP_KERNEL);
+ if (!info_list)
+ return 0;
+
+ while (!list_empty(from_page_list) && !list_empty(to_page_list)) {
+ unsigned long nr_added_pages;
+ INIT_LIST_HEAD(&exchange_list);
+
+ nr_added_pages = add_pages_to_exchange_list(from_page_list, to_page_list,
+ info_list, &exchange_list, batch_size);
+
+ /*
+ * Nothing to exchange, we bail out.
+ *
+ * In case from_page_list and to_page_list both only have file-backed
+ * pages left */
+ if (!nr_added_pages)
+ break;
+
+ added_size += nr_added_pages;
+
+ VM_BUG_ON(added_size > info_list_size);
+
+ if (migrate_concur)
+ exchange_pages_concur(&exchange_list, mode, MR_SYSCALL);
+ else
+ exchange_pages(&exchange_list, mode, MR_SYSCALL);
+
+ memset(info_list, 0, sizeof(struct exchange_page_info)*batch_size);
+ }
+
+ kvfree(info_list);
+
+ return info_list_size;
+}
+
static int do_mm_manage(struct task_struct *p, struct mm_struct *mm,
const nodemask_t *slow, const nodemask_t *fast,
unsigned long nr_pages, int flags)
@@ -261,6 +403,7 @@ static int do_mm_manage(struct task_struct *p, struct mm_struct *mm,
bool migrate_concur = flags & MPOL_MF_MOVE_CONCUR;
bool migrate_dma = flags & MPOL_MF_MOVE_DMA;
bool move_hot_and_cold_pages = flags & MPOL_MF_MOVE_ALL;
+ bool migrate_exchange_pages = flags & MPOL_MF_EXCHANGE;
struct mem_cgroup *memcg = mem_cgroup_from_task(p);
int err = 0;
unsigned long nr_isolated_slow_pages;
@@ -338,6 +481,35 @@ static int do_mm_manage(struct task_struct *p, struct mm_struct *mm,
&nr_isolated_fast_base_pages, &nr_isolated_fast_huge_pages,
move_hot_and_cold_pages?ISOLATE_HOT_AND_COLD_PAGES:ISOLATE_COLD_PAGES);
+ if (migrate_exchange_pages) {
+ unsigned long nr_exchange_pages;
+
+ /*
+ * base pages can include file-backed ones, we do not handle them
+ * at the moment
+ */
+ if (!thp_migration_supported()) {
+ nr_exchange_pages = exchange_pages_between_nodes(nr_isolated_slow_base_pages,
+ nr_isolated_fast_base_pages, &slow_base_page_list,
+ &fast_base_page_list, migration_batch_size, false, mode);
+
+ nr_isolated_fast_base_pages -= nr_exchange_pages;
+ }
+
+ /* THP page exchange */
+ nr_exchange_pages = exchange_pages_between_nodes(nr_isolated_slow_huge_pages,
+ nr_isolated_fast_huge_pages, &slow_huge_page_list,
+ &fast_huge_page_list, migration_batch_size, true, mode);
+
+ /* split THP above, so we do not need to multiply the counter */
+ if (!thp_migration_supported())
+ nr_isolated_fast_huge_pages -= nr_exchange_pages;
+ else
+ nr_isolated_fast_huge_pages -= nr_exchange_pages * HPAGE_PMD_NR;
+
+ goto migrate_out;
+ } else {
+migrate_out:
/* Migrate pages to slow node */
/* No multi-threaded migration for base pages */
nr_isolated_fast_base_pages -=
@@ -347,6 +519,7 @@ static int do_mm_manage(struct task_struct *p, struct mm_struct *mm,
nr_isolated_fast_huge_pages -=
migrate_to_node(&fast_huge_page_list, slow_nid, mode,
migration_batch_size);
+ }
}
if (nr_isolated_fast_base_pages != ULONG_MAX &&
--
2.7.4
