2 new /proc/vmstat fields are added, "thp_swapin" and
"thp_swapin_fallback" to count swapin a THP from swap device in one
piece and fallback to normal page swapin.
Signed-off-by: "Huang, Ying" <ying.hu...@intel.com>
Cc: "Kirill A. Shutemov" <kirill.shute...@linux.intel.com>
Cc: Andrea Arcangeli <aarca...@redhat.com>
Cc: Michal Hocko <mho...@kernel.org>
Cc: Johannes Weiner <han...@cmpxchg.org>
Cc: Shaohua Li <s...@kernel.org>
Cc: Hugh Dickins <hu...@google.com>
Cc: Minchan Kim <minc...@kernel.org>
Cc: Rik van Riel <r...@redhat.com>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: Naoya Horiguchi <n-horigu...@ah.jp.nec.com>
Cc: Zi Yan <zi....@cs.rutgers.edu>
Cc: Daniel Jordan <daniel.m.jor...@oracle.com>
---
Documentation/admin-guide/mm/transhuge.rst | 8 ++++++++
include/linux/vm_event_item.h | 2 ++
mm/huge_memory.c | 4 +++-
mm/page_io.c | 15 ++++++++++++---
mm/vmstat.c | 2 ++
5 files changed, 27 insertions(+), 4 deletions(-)
diff --git a/Documentation/admin-guide/mm/transhuge.rst
b/Documentation/admin-guide/mm/transhuge.rst
index 7ab93a8404b9..85e33f785fd7 100644
--- a/Documentation/admin-guide/mm/transhuge.rst
+++ b/Documentation/admin-guide/mm/transhuge.rst
@@ -364,6 +364,14 @@ thp_swpout_fallback
Usually because failed to allocate some continuous swap space
for the huge page.
+thp_swpin
+ is incremented every time a huge page is swapin in one piece
+ without splitting.
+
+thp_swpin_fallback
+ is incremented if a huge page has to be split during swapin.
+ Usually because failed to allocate a huge page.
+
As the system ages, allocating huge pages may be expensive as the
system uses memory compaction to copy data around memory to free a
huge page for use. There are some counters in ``/proc/vmstat`` to help
diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 47a3441cf4c4..c20b655cfdcc 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -88,6 +88,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
THP_ZERO_PAGE_ALLOC_FAILED,
THP_SWPOUT,
THP_SWPOUT_FALLBACK,
+ THP_SWPIN,
+ THP_SWPIN_FALLBACK,
#endif
#ifdef CONFIG_MEMORY_BALLOON
BALLOON_INFLATE,
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 561f3fb3d888..d3ee25ffeaaf 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1724,8 +1724,10 @@ int do_huge_pmd_swap_page(struct vm_fault *vmf, pmd_t
orig_pmd)
/* swapoff occurs under us */
} else if (ret == -EINVAL)
ret = 0;
- else
+ else {
+ count_vm_event(THP_SWPIN_FALLBACK);
goto fallback;
+ }
}
delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
goto out;
diff --git a/mm/page_io.c b/mm/page_io.c
index d4d1c89bcddd..8fd1f3ef83c4 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -348,6 +348,15 @@ int __swap_writepage(struct page *page, struct
writeback_control *wbc,
return ret;
}
+static inline void count_swpin_vm_event(struct page *page)
+{
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ if (unlikely(PageTransHuge(page)))
+ count_vm_event(THP_SWPIN);
+#endif
+ count_vm_events(PSWPIN, hpage_nr_pages(page));
+}
+
int swap_readpage(struct page *page, bool synchronous)
{
struct bio *bio;
@@ -371,7 +380,7 @@ int swap_readpage(struct page *page, bool synchronous)
ret = mapping->a_ops->readpage(swap_file, page);
if (!ret)
- count_vm_event(PSWPIN);
+ count_swpin_vm_event(page);
return ret;
}
@@ -382,7 +391,7 @@ int swap_readpage(struct page *page, bool synchronous)
unlock_page(page);
}
- count_vm_event(PSWPIN);
+ count_swpin_vm_event(page);
return 0;
}
@@ -401,7 +410,7 @@ int swap_readpage(struct page *page, bool synchronous)
get_task_struct(current);
bio->bi_private = current;
bio_set_op_attrs(bio, REQ_OP_READ, 0);
- count_vm_event(PSWPIN);
+ count_swpin_vm_event(page);
bio_get(bio);
qc = submit_bio(bio);
while (synchronous) {
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 83b30edc2f7f..80a731e9a5e5 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1265,6 +1265,8 @@ const char * const vmstat_text[] = {
"thp_zero_page_alloc_failed",
"thp_swpout",
"thp_swpout_fallback",
+ "thp_swpin",
+ "thp_swpin_fallback",
#endif
#ifdef CONFIG_MEMORY_BALLOON
"balloon_inflate",
--
2.18.1
