[RFC][PATCH] mm: ksm: add MAP_MERGEABLE mmap() as a KSM shortcut

2014-02-12 Thread Dave Hansen
We are starting to see substantial amounts (seconds) of latency being incurred by users of mmap_sem in the worst case. It is very common to see them spike up in to the tens-of-ms range. Any acquisition, especially for write, is a potential problem. The aggravating factor here is that we have

[RFC][PATCH] mm: ksm: add MAP_MERGEABLE mmap() as a KSM shortcut

2014-02-12 Thread Dave Hansen
We are starting to see substantial amounts (seconds) of latency being incurred by users of mmap_sem in the worst case. It is very common to see them spike up in to the tens-of-ms range. Any acquisition, especially for write, is a potential problem. The aggravating factor here is that we have