On Mon, Sep 16, 2013 at 08:06:30PM +0530, Aneesh Kumar K.V wrote: > Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> writes: > > > Hi, > > > > Kirill posted split_ptl patchset for thp today, so in this version > > I post only hugetlbfs part. I added Kconfig variables in following > > Kirill's patches (although without CONFIG_SPLIT_*_PTLOCK_CPUS.) > > > > This patch changes many lines, but all are in hugetlbfs specific code, > > so I think we can apply this independent of thp patches. > > ----- > > From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> > > Date: Fri, 13 Sep 2013 18:12:30 -0400 > > Subject: [PATCH v4] hugetlbfs: support split page table lock > > > > Currently all of page table handling by hugetlbfs code are done under > > mm->page_table_lock. So when a process have many threads and they heavily > > access to the memory, lock contention happens and impacts the performance. > > > > This patch makes hugepage support split page table lock so that we use > > page->ptl of the leaf node of page table tree which is pte for normal pages > > but can be pmd and/or pud for hugepages of some architectures. > > > > ChangeLog v4: > > - introduce arch dependent macro ARCH_ENABLE_SPLIT_HUGETLB_PTLOCK > > (only defined for x86 for now) > > - rename USE_SPLIT_PTLOCKS_HUGETLB to USE_SPLIT_HUGETLB_PTLOCKS > > Can we have separate locking for THP and hugetlb ? I think yes, because thp code and hugetlbfs code are clearly separated and we can execute only one of them on the same vma. > Doesn't both require us to > use same locking when updating pmd ? I think no for the same reason. Thanks, Naoya Horiguchi -- 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>