On Fri 03-08-12 22:16:52, Hillf Danton wrote: > On Thu, Aug 2, 2012 at 10:16 PM, Michal Hocko <mhocko@xxxxxxx> wrote: > > This patch addresses the issue by moving pmd_alloc into huge_pmd_share > > which guarantees that the shared pud is populated in the same > > critical section as pmd. > > Is i_mmap_mutex for guarding new pmd allocation? It doesn't guard the pmd allocation itself it just makes sure that pud population and pmd_allocation are done atomicaly wrt. other processes to share the same pmd because sharing is synchronized by i_mmap_mutex. > Is regression introduced if sharing is unavailable? No. The bug is about the sharing as the changelog describes. -- Michal Hocko SUSE Labs -- 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>