On Tue 28-05-13 15:52:50, Naoya Horiguchi wrote: > Currently all of page table handling by hugetlbfs code are done under > mm->page_table_lock. This is not optimal because there can be lock > contentions between unrelated components using this lock. While I agree with such a change in general I am a bit afraid of all subtle tweaks in the mm code that make hugetlb special. Maybe there are none for page_table_lock but I am not 100% sure. So this might be really tricky and it is not necessary for your further patches, is it? How have you tested this? > 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. > > Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> > --- > arch/x86/mm/hugetlbpage.c | 6 ++-- > include/linux/hugetlb.h | 18 ++++++++++ > mm/hugetlb.c | 84 ++++++++++++++++++++++++++++------------------- This doesn't seem to be the complete story. At least not from the trivial: $ find arch/ -name "*hugetlb*" | xargs git grep "page_table_lock" -- arch/powerpc/mm/hugetlbpage.c: spin_lock(&mm->page_table_lock); arch/powerpc/mm/hugetlbpage.c: spin_unlock(&mm->page_table_lock); arch/tile/mm/hugetlbpage.c: spin_lock(&mm->page_table_lock); arch/tile/mm/hugetlbpage.c: spin_unlock(&mm->page_table_lock); arch/x86/mm/hugetlbpage.c: * called with vma->vm_mm->page_table_lock held. -- 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>