Messages in this thread | | | Date | Tue, 15 May 2018 13:38:12 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH -mm] mm, hugetlb: Pass fault address to no page handler |
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On Tue, May 15, 2018 at 08:57:56AM +0800, Huang, Ying wrote: > From: Huang Ying <ying.huang@intel.com> > > This is to take better advantage of huge page clearing > optimization (c79b57e462b5d, "mm: hugetlb: clear target sub-page last > when clearing huge page"). Which will clear to access sub-page last > to avoid the cache lines of to access sub-page to be evicted when > clearing other sub-pages. This needs to get the address of the > sub-page to access, that is, the fault address inside of the huge > page. So the hugetlb no page fault handler is changed to pass that > information. This will benefit workloads which don't access the begin > of the huge page after page fault. > > With this patch, the throughput increases ~28.1% in vm-scalability > anon-w-seq test case with 88 processes on a 2 socket Xeon E5 2699 v4 > system (44 cores, 88 threads). The test case creates 88 processes, > each process mmap a big anonymous memory area and writes to it from > the end to the begin. For each process, other processes could be seen > as other workload which generates heavy cache pressure. At the same > time, the cache miss rate reduced from ~36.3% to ~25.6%, the > IPC (instruction per cycle) increased from 0.3 to 0.37, and the time > spent in user space is reduced ~19.3% > > Signed-off-by: "Huang, Ying" <ying.huang@intel.com> > Cc: Andrea Arcangeli <aarcange@redhat.com> > Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> > Cc: Andi Kleen <andi.kleen@intel.com> > Cc: Jan Kara <jack@suse.cz> > Cc: Michal Hocko <mhocko@suse.com> > Cc: Matthew Wilcox <mawilcox@microsoft.com> > Cc: Hugh Dickins <hughd@google.com> > Cc: Minchan Kim <minchan@kernel.org> > Cc: Shaohua Li <shli@fb.com> > Cc: Christopher Lameter <cl@linux.com> > Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> > Cc: Punit Agrawal <punit.agrawal@arm.com> > Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> > --- > mm/hugetlb.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 129088710510..3de6326abf39 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -3677,7 +3677,7 @@ int huge_add_to_page_cache(struct page *page, struct address_space *mapping, > > static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, > struct address_space *mapping, pgoff_t idx, > - unsigned long address, pte_t *ptep, unsigned int flags) > + unsigned long faddress, pte_t *ptep, unsigned int flags) > { > struct hstate *h = hstate_vma(vma); > int ret = VM_FAULT_SIGBUS; > @@ -3686,6 +3686,7 @@ static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, > struct page *page; > pte_t new_pte; > spinlock_t *ptl; > + unsigned long address = faddress & huge_page_mask(h);
faddress? I would rather keep it address and rename maked out variable to 'haddr'. We use 'haddr' for the cause in other places.
-- Kirill A. Shutemov
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