From: Johannes Weiner <hannes@xxxxxxxxxxx>
Add mem_cgroup_prepare_migration() and mem_cgroup_end_migration() calls
into do_huge_pmd_numa_page(), and fix mem_cgroup_prepare_migration() to
account for a Transparent Huge Page correctly without bugging.
Tested-by: Zhouping Liu <zliu@xxxxxxxxxx>
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
---
mm/huge_memory.c | 16 ++++++++++++++++
mm/memcontrol.c | 7 +++++--
2 files changed, 21 insertions(+), 2 deletions(-)
--- mmotm/mm/huge_memory.c 2012-11-09 09:43:46.892046342 -0800
+++ linux/mm/huge_memory.c 2012-11-13 14:51:04.000321370 -0800
@@ -750,6 +750,7 @@ void do_huge_pmd_numa_page(struct mm_str
unsigned int flags, pmd_t entry)
{
unsigned long haddr = address & HPAGE_PMD_MASK;
+ struct mem_cgroup *memcg = NULL;
struct page *new_page = NULL;
struct page *page = NULL;
int node, lru;
@@ -840,6 +841,14 @@ migrate:
return;
}
+ /*
+ * Traditional migration needs to prepare the memcg charge
+ * transaction early to prevent the old page from being
+ * uncharged when installing migration entries. Here we can
+ * save the potential rollback and start the charge transfer
+ * only when migration is already known to end successfully.
+ */
+ mem_cgroup_prepare_migration(page, new_page, &memcg);
entry = mk_pmd(new_page, vma->vm_page_prot);
entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
@@ -850,6 +859,12 @@ migrate:
set_pmd_at(mm, haddr, pmd, entry);
update_mmu_cache_pmd(vma, address, entry);
page_remove_rmap(page);
+ /*
+ * Finish the charge transaction under the page table lock to
+ * prevent split_huge_page() from dividing up the charge
+ * before it's fully transferred to the new page.
+ */
+ mem_cgroup_end_migration(memcg, page, new_page, true);
spin_unlock(&mm->page_table_lock);
put_page(page); /* Drop the rmap reference */
@@ -860,6 +875,7 @@ migrate:
put_page(page); /* drop the LRU isolation reference */
unlock_page(new_page);
+
unlock_page(page);
put_page(page); /* Drop the local reference */
--- mmotm/mm/memcontrol.c 2012-11-09 09:43:46.896046342 -0800
+++ linux/mm/memcontrol.c 2012-11-13 14:51:04.004321370 -0800
@@ -4186,15 +4186,18 @@ void mem_cgroup_prepare_migration(struct
struct mem_cgroup **memcgp)
{
struct mem_cgroup *memcg = NULL;
+ unsigned int nr_pages = 1;
struct page_cgroup *pc;
enum charge_type ctype;
*memcgp = NULL;
- VM_BUG_ON(PageTransHuge(page));
if (mem_cgroup_disabled())
return;
+ if (PageTransHuge(page))
+ nr_pages <<= compound_order(page);
+
pc = lookup_page_cgroup(page);
lock_page_cgroup(pc);
if (PageCgroupUsed(pc)) {
@@ -4256,7 +4259,7 @@ void mem_cgroup_prepare_migration(struct
* charged to the res_counter since we plan on replacing the
* old one and only one page is going to be left afterwards.
*/
- __mem_cgroup_commit_charge(memcg, newpage, 1, ctype, false);
+ __mem_cgroup_commit_charge(memcg, newpage, nr_pages, ctype, false);
}
/* remove redundant charge if migration failed*/
--
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