On 09.02.23 13:01, yang.yang29@xxxxxxxxxx wrote:
diff --git a/mm/ksm.c b/mm/ksm.c
index 652c088f9786..72c0722be280 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -276,6 +276,9 @@ static unsigned int zero_checksum __read_mostly;
/* Whether to merge empty (zeroed) pages with actual zero pages */
static bool ksm_use_zero_pages __read_mostly;
+/* The number of zero pages placed by KSM use_zero_pages */
+static unsigned long ksm_zero_pages_sharing;
Does this count how many zero pages are currently placed or how many
rmap items with ZERO_PAGE_FLAG are in the system?
Yes, it counts how many ksm zero pages are currently placed. and we use
rmap items with ZERO_PAGE_FLAG to record these zero page, similar to
ksm_pages_sharing and ksm_pages_shared which are recorded by the rmap_items
with STABLE_FLAG.
IOW, if someone triggers MADV_DONTNEED on such a zeropage, the counter
will not get updated, correct?
Well, the counter can get updated as someone triggers MADV_DONTNEED on such
a zeropage. You might write a simple code to test it.
Interesting, I'll have a look how that will be triggered.
--
Thanks,
David / dhildenb
