Subject: [PATCH] hugetlb: vmstat events for huge page allocations

Allocating huge pages directly from the buddy allocator is not guaranteed to
succeed.  Success depends on several factors (such as the amount of physical
memory available and the level of fragmentation).  With the addition of
dynamic hugetlb pool resizing, allocations can occur much more frequently.
For these reasons it is desirable to keep track of huge page allocation
successes and failures.

Add two new vmstat entries to track huge page allocations that succeed and
fail.  The presence of the two entries is contingent upon CONFIG_HUGETLB_PAGE
being enabled.

[akpm@linux-foundation.org: reduced ifdeffery]
Signed-off-by: Adam Litke <agl@us.ibm.com>
Signed-off-by: Eric Munson <ebmunson@us.ibm.com>
Tested-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Andy Whitcroft <apw@shadowen.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index e726b6d464951b21debc8ace283343b26e5d3f57..e83b69346d2342fd2927278d40f98c4fb1afdff3 100644 (file)
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -25,6 +25,7 @@
 #define HIGHMEM_ZONE(xx)
 #endif
 
+
 #define FOR_ALL_ZONES(xx) DMA_ZONE(xx) DMA32_ZONE(xx) xx##_NORMAL HIGHMEM_ZONE(xx) , xx##_MOVABLE
 
 enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
@@ -37,6 +38,9 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
                FOR_ALL_ZONES(PGSCAN_DIRECT),
                PGINODESTEAL, SLABS_SCANNED, KSWAPD_STEAL, KSWAPD_INODESTEAL,
                PAGEOUTRUN, ALLOCSTALL, PGROTATED,
+#ifdef CONFIG_HUGETLB_PAGE
+               HTLB_BUDDY_PGALLOC, HTLB_BUDDY_PGALLOC_FAIL,
+#endif
                NR_VM_EVENT_ITEMS
 };
 

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 93ea46a0fba46017c9ac1d87a66310c7d0a91fec..8deae4eb9696f3196d32a1d6652ed7e42841f9e9 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -242,6 +242,11 @@ static int alloc_fresh_huge_page(void)
                hugetlb_next_nid = next_nid;
        } while (!page && hugetlb_next_nid != start_nid);
 
+       if (ret)
+               count_vm_event(HTLB_BUDDY_PGALLOC);
+       else
+               count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
+
        return ret;
 }
 
@@ -302,9 +307,11 @@ static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma,
                 */
                nr_huge_pages_node[nid]++;
                surplus_huge_pages_node[nid]++;
+               __count_vm_event(HTLB_BUDDY_PGALLOC);
        } else {
                nr_huge_pages--;
                surplus_huge_pages--;
+               __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
        }
        spin_unlock(&hugetlb_lock);
 

diff --git a/mm/vmstat.c b/mm/vmstat.c
index 879bcc0a1d4c77868880555409bab4918c390f8f..4c21670f8d91de346cad33f8a0c5d1811a82a573 100644 (file)
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -645,6 +645,10 @@ static const char * const vmstat_text[] = {
        "allocstall",
 
        "pgrotated",
+#ifdef CONFIG_HUGETLB_PAGE
+       "htlb_buddy_alloc_success",
+       "htlb_buddy_alloc_fail",
+#endif
 #endif
 };