diff options
author | Christian Borntraeger <borntraeger@de.ibm.com> | 2007-11-20 11:13:36 +0100 |
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committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2007-11-20 11:13:46 +0100 |
commit | ce7e9fae8db07af4080e868f4588f8f095f803dc (patch) | |
tree | 000a6cc755ee35ef3cfc0795c13ed500dc5457de /mm/shmem.c | |
parent | b8e7a54cd06b0b0174029ef3a7f5a1415a2c28f2 (diff) |
[S390] Optimize storage key handling for anonymous pages
page_mkclean used to call page_clear_dirty for every given page. This
is different to all other architectures, where the dirty bit in the
PTEs is only resetted, if page_mapping() returns a non-NULL pointer.
We can move the page_test_dirty/page_clear_dirty sequence into the
2nd if to avoid unnecessary iske/sske sequences, which are expensive.
This change also helps kvm for s390 as the host must transfer the
dirty bit into the guest status bits. By moving the page_clear_dirty
operation into the 2nd if, the vm will only call page_clear_dirty
for pages where it walks the mapping anyway. There it calls
ptep_clear_flush for writable ptes, so we can transfer the dirty bit
to the guest.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'mm/shmem.c')
0 files changed, 0 insertions, 0 deletions