From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754286AbcFPMUI (ORCPT ); Thu, 16 Jun 2016 08:20:08 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:32813 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753846AbcFPMUG (ORCPT ); Thu, 16 Jun 2016 08:20:06 -0400 Date: Thu, 16 Jun 2016 14:20:02 +0200 From: Michal Hocko To: "Kirill A. Shutemov" Cc: Linus Torvalds , Andrew Morton , Rik van Riel , Mel Gorman , "Huang, Ying" , Minchan Kim , Vinayak Menon , Dave Hansen , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/2] Revert "mm: make faultaround produce old ptes" Message-ID: <20160616122001.GJ6836@dhcp22.suse.cz> References: <1465893750-44080-1-git-send-email-kirill.shutemov@linux.intel.com> <1465893750-44080-2-git-send-email-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1465893750-44080-2-git-send-email-kirill.shutemov@linux.intel.com> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 14-06-16 11:42:29, Kirill A. Shutemov wrote: > This reverts commit 5c0a85fad949212b3e059692deecdeed74ae7ec7. > > The commit causes ~6% regression in unixbench. Is the regression fully explained? My understanding from the email thread is that this is suspiciously too high. It is not like I would be against the revert but having an explanation would be really appreciated. > Let's revert it for now and consider other solution for reclaim problem > later. > > Signed-off-by: Kirill A. Shutemov > Reported-by: "Huang, Ying" > --- > include/linux/mm.h | 2 +- > mm/filemap.c | 2 +- > mm/memory.c | 23 +++++------------------ > 3 files changed, 7 insertions(+), 20 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 5df5feb49575..ece042dfe23c 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -602,7 +602,7 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) > } > > void do_set_pte(struct vm_area_struct *vma, unsigned long address, > - struct page *page, pte_t *pte, bool write, bool anon, bool old); > + struct page *page, pte_t *pte, bool write, bool anon); > #endif > > /* > diff --git a/mm/filemap.c b/mm/filemap.c > index 00ae878b2a38..20f3b1f33f0e 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -2186,7 +2186,7 @@ repeat: > if (file->f_ra.mmap_miss > 0) > file->f_ra.mmap_miss--; > addr = address + (page->index - vmf->pgoff) * PAGE_SIZE; > - do_set_pte(vma, addr, page, pte, false, false, true); > + do_set_pte(vma, addr, page, pte, false, false); > unlock_page(page); > goto next; > unlock: > diff --git a/mm/memory.c b/mm/memory.c > index 15322b73636b..61fe7e7b56bf 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -2877,7 +2877,7 @@ static int __do_fault(struct vm_area_struct *vma, unsigned long address, > * vm_ops->map_pages. > */ > void do_set_pte(struct vm_area_struct *vma, unsigned long address, > - struct page *page, pte_t *pte, bool write, bool anon, bool old) > + struct page *page, pte_t *pte, bool write, bool anon) > { > pte_t entry; > > @@ -2885,8 +2885,6 @@ void do_set_pte(struct vm_area_struct *vma, unsigned long address, > entry = mk_pte(page, vma->vm_page_prot); > if (write) > entry = maybe_mkwrite(pte_mkdirty(entry), vma); > - if (old) > - entry = pte_mkold(entry); > if (anon) { > inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); > page_add_new_anon_rmap(page, vma, address, false); > @@ -3032,20 +3030,9 @@ static int do_read_fault(struct mm_struct *mm, struct vm_area_struct *vma, > */ > if (vma->vm_ops->map_pages && fault_around_bytes >> PAGE_SHIFT > 1) { > pte = pte_offset_map_lock(mm, pmd, address, &ptl); > - if (!pte_same(*pte, orig_pte)) > - goto unlock_out; > do_fault_around(vma, address, pte, pgoff, flags); > - /* Check if the fault is handled by faultaround */ > - if (!pte_same(*pte, orig_pte)) { > - /* > - * Faultaround produce old pte, but the pte we've > - * handler fault for should be young. > - */ > - pte_t entry = pte_mkyoung(*pte); > - if (ptep_set_access_flags(vma, address, pte, entry, 0)) > - update_mmu_cache(vma, address, pte); > + if (!pte_same(*pte, orig_pte)) > goto unlock_out; > - } > pte_unmap_unlock(pte, ptl); > } > > @@ -3060,7 +3047,7 @@ static int do_read_fault(struct mm_struct *mm, struct vm_area_struct *vma, > put_page(fault_page); > return ret; > } > - do_set_pte(vma, address, fault_page, pte, false, false, false); > + do_set_pte(vma, address, fault_page, pte, false, false); > unlock_page(fault_page); > unlock_out: > pte_unmap_unlock(pte, ptl); > @@ -3111,7 +3098,7 @@ static int do_cow_fault(struct mm_struct *mm, struct vm_area_struct *vma, > } > goto uncharge_out; > } > - do_set_pte(vma, address, new_page, pte, true, true, false); > + do_set_pte(vma, address, new_page, pte, true, true); > mem_cgroup_commit_charge(new_page, memcg, false, false); > lru_cache_add_active_or_unevictable(new_page, vma); > pte_unmap_unlock(pte, ptl); > @@ -3164,7 +3151,7 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma, > put_page(fault_page); > return ret; > } > - do_set_pte(vma, address, fault_page, pte, true, false, false); > + do_set_pte(vma, address, fault_page, pte, true, false); > pte_unmap_unlock(pte, ptl); > > if (set_page_dirty(fault_page)) > -- > 2.8.1 > -- Michal Hocko SUSE Labs