On 07/27/2017 06:26 PM, Michal Hocko wrote:
On Thu 27-07-17 14:07:55, Aneesh Kumar K.V wrote:
We can now use this to set pmd page table entries to absolute values. THP
need to ensure that we always update pmd PTE entries such that we never mark
the pmd none. pmdp_establish helps in implementing that.
This doesn't flush the tlb. Based on the old_pmd value returned caller can
decide to call flush_pmd_tlb_range()
_Why_ do we need this. It doesn't really help that the newly added
function is not used so we could check that...
We were looking at having pmdp_establish used by the core code. But i
guess Kirill ended up using pmdp_invalidate. If we don't have
pmdp_establish usage in core code, we can drop this. This is to help
Kiril make progress with series at
https://lkml.kernel.org/r/20170615145224.66200-1-kirill.shutemov@xxxxxxxxxxxxxxx
Also thinking about the interface further, I guess pmdp_establish
interface is some what confusing. So we may want to rethink this
further. I know that i asked for pmdp_establish in earlier review of
Kirill's patchset. But now looking back i am not sure we can clearly
explain only semantic requirement of pmdp_establish. One thing we may
want to clarify is whether we should retain the Reference and change bit
from the old entry when we are doing a pmdp_establish ?
Kirill,
Considering core code is still only using pmdp_invalidate(), we may want
to drop this interface completely ?
-aneesh
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
