memcg: adjust to support new THP refcounting

As with rmap, with new refcounting we cannot rely on PageTransHuge() to
check if we need to charge size of huge page form the cgroup.  We need
to get information from caller to know whether it was mapped with PMD or
PTE.

We do uncharge when last reference on the page gone.  At that point if
we see PageTransHuge() it means we need to unchange whole huge page.

The tricky part is partial unmap -- when we try to unmap part of huge
page.  We don't do a special handing of this situation, meaning we don't
uncharge the part of huge page unless last user is gone or
split_huge_page() is triggered.  In case of cgroup memory pressure
happens the partial unmapped page will be split through shrinker.  This
should be good enough.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 9 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index d271932f9ef9..b98e1011858c 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -810,7 +810,8 @@ int shmem_unuse(swp_entry_t swap, struct page *page)
          * the shmem_swaplist_mutex which might hold up shmem_writepage().
          * Charged back to the user (not to caller) when swap account is used.
          */
-        error = mem_cgroup_try_charge(page, current->mm, GFP_KERNEL, &memcg);
+        error = mem_cgroup_try_charge(page, current->mm, GFP_KERNEL, &memcg,
+                        false);
         if (error)
                 goto out;
         /* No radix_tree_preload: swap entry keeps a place for page in tree */
@@ -833,9 +834,9 @@ int shmem_unuse(swp_entry_t swap, struct page *page)
         if (error) {
                 if (error != -ENOMEM)
                         error = 0;
-                mem_cgroup_cancel_charge(page, memcg);
+                mem_cgroup_cancel_charge(page, memcg, false);
         } else
-                mem_cgroup_commit_charge(page, memcg, true);
+                mem_cgroup_commit_charge(page, memcg, true, false);
 out:
         unlock_page(page);
         page_cache_release(page);
@@ -1218,7 +1219,8 @@ repeat:
                                 goto failed;
                 }
 
-                error = mem_cgroup_try_charge(page, current->mm, gfp, &memcg);
+                error = mem_cgroup_try_charge(page, current->mm, gfp, &memcg,
+                                false);
                 if (!error) {
                         error = shmem_add_to_page_cache(page, mapping, index,
                                                 swp_to_radix_entry(swap));
@@ -1235,14 +1237,14 @@ repeat:
                          * "repeat": reading a hole and writing should succeed.
                          */
                         if (error) {
-                                mem_cgroup_cancel_charge(page, memcg);
+                                mem_cgroup_cancel_charge(page, memcg, false);
                                 delete_from_swap_cache(page);
                         }
                 }
                 if (error)
                         goto failed;
 
-                mem_cgroup_commit_charge(page, memcg, true);
+                mem_cgroup_commit_charge(page, memcg, true, false);
 
                 spin_lock(&info->lock);
                 info->swapped--;
@@ -1281,7 +1283,8 @@ repeat:
                 if (sgp == SGP_WRITE)
                         __SetPageReferenced(page);
 
-                error = mem_cgroup_try_charge(page, current->mm, gfp, &memcg);
+                error = mem_cgroup_try_charge(page, current->mm, gfp, &memcg,
+                                false);
                 if (error)
                         goto decused;
                 error = radix_tree_maybe_preload(gfp & GFP_RECLAIM_MASK);
@@ -1291,10 +1294,10 @@ repeat:
                         radix_tree_preload_end();
                 }
                 if (error) {
-                        mem_cgroup_cancel_charge(page, memcg);
+                        mem_cgroup_cancel_charge(page, memcg, false);
                         goto decused;
                 }
-                mem_cgroup_commit_charge(page, memcg, false);
+                mem_cgroup_commit_charge(page, memcg, false, false);
                 lru_cache_add_anon(page);
 
                 spin_lock(&info->lock);