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authorChristian Borntraeger <borntraeger@de.ibm.com>2008-03-25 18:47:12 +0100
committerAvi Kivity <avi@qumranet.com>2008-04-27 12:00:40 +0300
commit5b7baf05783b1ac97a510243d7e82293416a7cf6 (patch)
tree15b753206d9a3fd5edd0029405f8acfc69237861 /mm
parent402b08622d9ac6e32e25289573272e0f21bb58a7 (diff)
s390: KVM preparation: host memory management changes for s390 kvm
This patch changes the s390 memory management defintions to use the pgste field for dirty and reference bit tracking of host and guest code. Usually on s390, dirty and referenced are tracked in storage keys, which belong to the physical page. This changes with virtualization: The guest and host dirty/reference bits are defined to be the logical OR of the values for the mapping and the physical page. This patch implements the necessary changes in pgtable.h for s390. There is a common code change in mm/rmap.c, the call to page_test_and_clear_young must be moved. This is a no-op for all architecture but s390. page_referenced checks the referenced bits for the physiscal page and for all mappings: o The physical page is checked with page_test_and_clear_young. o The mappings are checked with ptep_test_and_clear_young and friends. Without pgstes (the current implementation on Linux s390) the physical page check is implemented but the mapping callbacks are no-ops because dirty and referenced are not tracked in the s390 page tables. The pgstes introduces guest and host dirty and reference bits for s390 in the host mapping. These mapping must be checked before page_test_and_clear_young resets the reference bit. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'mm')
-rw-r--r--mm/rmap.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index 997f06907b6..e9bb6b1093f 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -413,9 +413,6 @@ int page_referenced(struct page *page, int is_locked,
{
int referenced = 0;
- if (page_test_and_clear_young(page))
- referenced++;
-
if (TestClearPageReferenced(page))
referenced++;
@@ -433,6 +430,10 @@ int page_referenced(struct page *page, int is_locked,
unlock_page(page);
}
}
+
+ if (page_test_and_clear_young(page))
+ referenced++;
+
return referenced;
}