Re: [PATCH v5 6/6] mm: shmem: add mTHP counters for anonymous shmem

Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> · Wed, 12 Jun 2024 17:28:21 +0800

On 2024/6/12 16:04, Lance Yang wrote:
Hi Baolin,

On Tue, Jun 11, 2024 at 6:11 PM Baolin Wang
<baolin.wang@xxxxxxxxxxxxxxxxx> wrote:

Add mTHP counters for anonymous shmem.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
---
  include/linux/huge_mm.h |  3 +++
  mm/huge_memory.c        |  6 ++++++
  mm/shmem.c              | 18 +++++++++++++++---
  3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 909cfc67521d..212cca384d7e 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -281,6 +281,9 @@ enum mthp_stat_item {
         MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE,
         MTHP_STAT_SWPOUT,
         MTHP_STAT_SWPOUT_FALLBACK,
+       MTHP_STAT_FILE_ALLOC,
+       MTHP_STAT_FILE_FALLBACK,
+       MTHP_STAT_FILE_FALLBACK_CHARGE,
         __MTHP_STAT_COUNT
  };

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 1360a1903b66..3fbcd77f5957 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -555,6 +555,9 @@ DEFINE_MTHP_STAT_ATTR(anon_fault_fallback, MTHP_STAT_ANON_FAULT_FALLBACK);
  DEFINE_MTHP_STAT_ATTR(anon_fault_fallback_charge, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
  DEFINE_MTHP_STAT_ATTR(swpout, MTHP_STAT_SWPOUT);
  DEFINE_MTHP_STAT_ATTR(swpout_fallback, MTHP_STAT_SWPOUT_FALLBACK);
+DEFINE_MTHP_STAT_ATTR(file_alloc, MTHP_STAT_FILE_ALLOC);
+DEFINE_MTHP_STAT_ATTR(file_fallback, MTHP_STAT_FILE_FALLBACK);
+DEFINE_MTHP_STAT_ATTR(file_fallback_charge, MTHP_STAT_FILE_FALLBACK_CHARGE);

  static struct attribute *stats_attrs[] = {
         &anon_fault_alloc_attr.attr,
@@ -562,6 +565,9 @@ static struct attribute *stats_attrs[] = {
         &anon_fault_fallback_charge_attr.attr,
         &swpout_attr.attr,
         &swpout_fallback_attr.attr,
+       &file_alloc_attr.attr,
+       &file_fallback_attr.attr,
+       &file_fallback_charge_attr.attr,
         NULL,
  };

diff --git a/mm/shmem.c b/mm/shmem.c
index f5469c357be6..99bd3c34f0fb 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1773,6 +1773,9 @@ static struct folio *shmem_alloc_and_add_folio(struct vm_fault *vmf,

                         if (pages == HPAGE_PMD_NR)
                                 count_vm_event(THP_FILE_FALLBACK);
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+                       count_mthp_stat(order, MTHP_STAT_FILE_FALLBACK);
+#endif

Using the conditional compilation directives here is a bit weird :)
Would there be any issues if we were to drop them?

Will cause building errors if CONFIG_TRANSPARENT_HUGEPAGE is not enabled.


Since THP_FILE_FALLBACK is working as expected, MTHP_STAT_FILE_FALLBACK
should work as well without the conditional compilation directives, IIUC.

No, you should take a look at how count_mthp_stat() is defined :)







