Merge branch 'akpm' (patches from Andrew)

Merge updates from Andrew Morton:
 "Incoming:

   - a small number of updates to scripts/, ocfs2 and fs/buffer.c

   - most of MM

  I still have quite a lot of material (mostly not MM) staged after
  linux-next due to -next dependencies. I'll send those across next week
  as the preprequisites get merged up"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (135 commits)
  mm/page_io.c: annotate refault stalls from swap_readpage
  mm/Kconfig: fix trivial help text punctuation
  mm/Kconfig: fix indentation
  mm/memory_hotplug.c: remove __online_page_set_limits()
  mm: fix typos in comments when calling __SetPageUptodate()
  mm: fix struct member name in function comments
  mm/shmem.c: cast the type of unmap_start to u64
  mm: shmem: use proper gfp flags for shmem_writepage()
  mm/shmem.c: make array 'values' static const, makes object smaller
  userfaultfd: require CAP_SYS_PTRACE for UFFD_FEATURE_EVENT_FORK
  fs/userfaultfd.c: wp: clear VM_UFFD_MISSING or VM_UFFD_WP during userfaultfd_register()
  userfaultfd: wrap the common dst_vma check into an inlined function
  userfaultfd: remove unnecessary WARN_ON() in __mcopy_atomic_hugetlb()
  userfaultfd: use vma_pagesize for all huge page size calculation
  mm/madvise.c: use PAGE_ALIGN[ED] for range checking
  mm/madvise.c: replace with page_size() in madvise_inject_error()
  mm/mmap.c: make vma_merge() comment more easy to understand
  mm/hwpoison-inject: use DEFINE_DEBUGFS_ATTRIBUTE to define debugfs fops
  autonuma: reduce cache footprint when scanning page tables
  autonuma: fix watermark checking in migrate_balanced_pgdat()
  ...

1 files changed, 13 insertions, 2 deletions

diff --git a/mm/page_io.c b/mm/page_io.c
index 60a66a58b9bf..3a198deb8bb1 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -22,6 +22,7 @@
 #include <linux/writeback.h>
 #include <linux/frontswap.h>
 #include <linux/blkdev.h>
+#include <linux/psi.h>
 #include <linux/uio.h>
 #include <linux/sched/task.h>
 #include <asm/pgtable.h>
@@ -354,10 +355,19 @@ int swap_readpage(struct page *page, bool synchronous)
 	struct swap_info_struct *sis = page_swap_info(page);
 	blk_qc_t qc;
 	struct gendisk *disk;
+	unsigned long pflags;
 
 	VM_BUG_ON_PAGE(!PageSwapCache(page) && !synchronous, page);
 	VM_BUG_ON_PAGE(!PageLocked(page), page);
 	VM_BUG_ON_PAGE(PageUptodate(page), page);
+
+	/*
+	 * Count submission time as memory stall. When the device is congested,
+	 * or the submitting cgroup IO-throttled, submission can be a
+	 * significant part of overall IO time.
+	 */
+	psi_memstall_enter(&pflags);
+
 	if (frontswap_load(page) == 0) {
 		SetPageUptodate(page);
 		unlock_page(page);
@@ -371,7 +381,7 @@ int swap_readpage(struct page *page, bool synchronous)
 		ret = mapping->a_ops->readpage(swap_file, page);
 		if (!ret)
 			count_vm_event(PSWPIN);
-		return ret;
+		goto out;
 	}
 
 	ret = bdev_read_page(sis->bdev, swap_page_sector(page), page);
@@ -382,7 +392,7 @@ int swap_readpage(struct page *page, bool synchronous)
 		}
 
 		count_vm_event(PSWPIN);
-		return 0;
+		goto out;
 	}
 
 	ret = 0;
@@ -418,6 +428,7 @@ int swap_readpage(struct page *page, bool synchronous)
 	bio_put(bio);
 
 out:
+	psi_memstall_leave(&pflags);
 	return ret;
 }