The patch titled
Subject: mm, THP, swap: support to count THP swapin and its fallback
has been added to the -mm tree. Its filename is
mm-thp-swap-support-to-count-thp-swapin-and-its-fallback.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-thp-swap-support-to-count-thp-swapin-and-its-fallback.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-swap-support-to-count-thp-swapin-and-its-fallback.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Huang Ying <ying.huang@xxxxxxxxx>
Subject: mm, THP, swap: support to count THP swapin and its fallback
2 new /proc/vmstat fields are added, "thp_swapin" and
"thp_swapin_fallback" to count swapin a THP from swap device as a whole
and fallback to normal page swapin.
Link: http://lkml.kernel.org/r/20180622035151.6676-11-ying.huang@xxxxxxxxx
Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Shaohua Li <shli@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Zi Yan <zi.yan@xxxxxxxxxxxxxx>
Cc: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
diff -puN Documentation/admin-guide/mm/transhuge.rst~mm-thp-swap-support-to-count-thp-swapin-and-its-fallback Documentation/admin-guide/mm/transhuge.rst
--- a/Documentation/admin-guide/mm/transhuge.rst~mm-thp-swap-support-to-count-thp-swapin-and-its-fallback
+++ a/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 -puN include/linux/vm_event_item.h~mm-thp-swap-support-to-count-thp-swapin-and-its-fallback include/linux/vm_event_item.h
--- a/include/linux/vm_event_item.h~mm-thp-swap-support-to-count-thp-swapin-and-its-fallback
+++ a/include/linux/vm_event_item.h
@@ -88,6 +88,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PS
THP_ZERO_PAGE_ALLOC_FAILED,
THP_SWPOUT,
THP_SWPOUT_FALLBACK,
+ THP_SWPIN,
+ THP_SWPIN_FALLBACK,
#endif
#ifdef CONFIG_MEMORY_BALLOON
BALLOON_INFLATE,
diff -puN mm/huge_memory.c~mm-thp-swap-support-to-count-thp-swapin-and-its-fallback mm/huge_memory.c
--- a/mm/huge_memory.c~mm-thp-swap-support-to-count-thp-swapin-and-its-fallback
+++ a/mm/huge_memory.c
@@ -1665,8 +1665,10 @@ retry:
/* 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 -puN mm/page_io.c~mm-thp-swap-support-to-count-thp-swapin-and-its-fallback mm/page_io.c
--- a/mm/page_io.c~mm-thp-swap-support-to-count-thp-swapin-and-its-fallback
+++ a/mm/page_io.c
@@ -347,6 +347,15 @@ out:
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;
@@ -370,7 +379,7 @@ int swap_readpage(struct page *page, boo
ret = mapping->a_ops->readpage(swap_file, page);
if (!ret)
- count_vm_event(PSWPIN);
+ count_swpin_vm_event(page);
return ret;
}
@@ -381,7 +390,7 @@ int swap_readpage(struct page *page, boo
unlock_page(page);
}
- count_vm_event(PSWPIN);
+ count_swpin_vm_event(page);
return 0;
}
@@ -400,7 +409,7 @@ int swap_readpage(struct page *page, boo
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 -puN mm/vmstat.c~mm-thp-swap-support-to-count-thp-swapin-and-its-fallback mm/vmstat.c
--- a/mm/vmstat.c~mm-thp-swap-support-to-count-thp-swapin-and-its-fallback
+++ a/mm/vmstat.c
@@ -1263,6 +1263,8 @@ 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",
_
Patches currently in -mm which might be from ying.huang@xxxxxxxxx are
mm-clear_huge_page-move-order-algorithm-into-a-separate-function.patch
mm-huge-page-copy-target-sub-page-last-when-copy-huge-page.patch
mm-hugetlbfs-rename-address-to-haddr-in-hugetlb_cow.patch
mm-hugetlbfs-pass-fault-address-to-cow-handler.patch
mm-swap-fix-race-between-swapoff-and-some-swap-operations.patch
mm-swap-fix-race-between-swapoff-and-some-swap-operations-v6.patch
mm-fix-race-between-swapoff-and-mincore.patch
mm-thp-swap-enable-pmd-swap-operations-for-config_thp_swap.patch
mm-thp-swap-make-config_thp_swap-depends-on-config_swap.patch
mm-thp-swap-support-pmd-swap-mapping-in-swap_duplicate.patch
mm-thp-swap-support-pmd-swap-mapping-in-swapcache_free_cluster.patch
mm-thp-swap-support-pmd-swap-mapping-in-free_swap_and_cache-swap_free.patch
mm-thp-swap-support-pmd-swap-mapping-when-splitting-huge-pmd.patch
mm-thp-swap-support-pmd-swap-mapping-in-split_swap_cluster.patch
mm-thp-swap-support-to-read-a-huge-swap-cluster-for-swapin-a-thp.patch
mm-thp-swap-swapin-a-thp-as-a-whole.patch
mm-thp-swap-support-to-count-thp-swapin-and-its-fallback.patch
mm-thp-swap-add-sysfs-interface-to-configure-thp-swapin.patch
mm-thp-swap-support-pmd-swap-mapping-in-swapoff.patch
mm-thp-swap-support-pmd-swap-mapping-in-madvise_free.patch
mm-cgroup-thp-swap-support-to-move-swap-account-for-pmd-swap-mapping.patch
mm-thp-swap-support-to-copy-pmd-swap-mapping-when-fork.patch
mm-thp-swap-free-pmd-swap-mapping-when-zap_huge_pmd.patch
mm-thp-swap-support-pmd-swap-mapping-for-madv_willneed.patch
mm-thp-swap-support-pmd-swap-mapping-in-mincore.patch
mm-thp-swap-support-pmd-swap-mapping-in-common-path.patch
mm-thp-swap-create-pmd-swap-mapping-when-unmap-the-thp.patch
mm-thp-avoid-to-split-thp-when-reclaim-madv_free-thp.patch
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