From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNWANTED_LANGUAGE_BODY,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C20D2C433DF for ; Fri, 15 May 2020 04:10:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9FECE206F1 for ; Fri, 15 May 2020 04:10:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726205AbgEOEKc (ORCPT ); Fri, 15 May 2020 00:10:32 -0400 Received: from mail.loongson.cn ([114.242.206.163]:54194 "EHLO loongson.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726030AbgEOEKc (ORCPT ); Fri, 15 May 2020 00:10:32 -0400 Received: from kvm-dev1.localdomain (unknown [10.2.5.134]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9DxT98hFr5eHPU0AA--.1S3; Fri, 15 May 2020 12:10:10 +0800 (CST) From: Bibo Mao To: Thomas Bogendoerfer , Jiaxun Yang , Huacai Chen , Andrew Morton , Paul Burton , Dmitry Korotin , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Stafford Horne , Steven Price , Anshuman Khandual Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, Mike Rapoport , Sergei Shtylyov , "Maciej W. Rozycki" , linux-mm@kvack.org Subject: [PATCH 2/3] mm/memory.c: Update local TLB if PTE entry exists Date: Fri, 15 May 2020 12:10:08 +0800 Message-Id: <1589515809-32422-2-git-send-email-maobibo@loongson.cn> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1589515809-32422-1-git-send-email-maobibo@loongson.cn> References: <1589515809-32422-1-git-send-email-maobibo@loongson.cn> X-CM-TRANSID: AQAAf9DxT98hFr5eHPU0AA--.1S3 X-Coremail-Antispam: 1UD129KBjvJXoW3WFyfuw4kur1fWFy5Kw4UJwb_yoW7trWfpr yfCa1DXF4xXr18Zr4xXr4qvr15Za4rJa48Jr9xKw1Fv39xXr4fuay5G3yFvFZ5GryFqwsr Jr4jgF48Zayxuw7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPIb7Iv0xC_Kw4lb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI 8067AKxVWUGwA2048vs2IY020Ec7CjxVAFwI0_Gr0_Xr1l8cAvFVAK0II2c7xJM28CjxkF 64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVWUCVW8JwA2z4x0Y4vE2Ix0cI8IcV CY1x0267AKxVW8JVWxJwA2z4x0Y4vEx4A2jsIE14v26r4UJVWxJr1l84ACjcxK6I8E87Iv 6xkF7I0E14v26F4UJVW0owAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzV Aqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S 6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7Mx kIecxEwVCm-wCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02 F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_GFv_Wr ylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7Cj xVAFwI0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r 1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07bw 5l8UUUUU= X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If there are two threads hitting page fault at the same page, one thread updates PTE entry and local TLB, the other can update local tlb also, rather than give up and do page fault again. --- Change in V2: - separate tlb update and add pte readable privilege into two patches Signed-off-by: Bibo Mao --- mm/memory.c | 44 +++++++++++++++++++++++++++----------------- 1 file changed, 27 insertions(+), 17 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index f703fe8..57748de 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1770,8 +1770,8 @@ static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr, } entry = pte_mkyoung(*pte); entry = maybe_mkwrite(pte_mkdirty(entry), vma); - if (ptep_set_access_flags(vma, addr, pte, entry, 1)) - update_mmu_cache(vma, addr, pte); + ptep_set_access_flags(vma, addr, pte, entry, 1); + update_mmu_cache(vma, addr, pte); } goto out_unlock; } @@ -2436,17 +2436,16 @@ static inline bool cow_user_page(struct page *dst, struct page *src, if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { /* * Other thread has already handled the fault - * and we don't need to do anything. If it's - * not the case, the fault will be triggered - * again on the same address. + * and update local tlb only */ + update_mmu_cache(vma, addr, vmf->pte); ret = false; goto pte_unlock; } entry = pte_mkyoung(vmf->orig_pte); - if (ptep_set_access_flags(vma, addr, vmf->pte, entry, 0)) - update_mmu_cache(vma, addr, vmf->pte); + ptep_set_access_flags(vma, addr, vmf->pte, entry, 0); + update_mmu_cache(vma, addr, vmf->pte); } /* @@ -2463,7 +2462,8 @@ static inline bool cow_user_page(struct page *dst, struct page *src, vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl); locked = true; if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { - /* The PTE changed under us. Retry page fault. */ + /* The PTE changed under us, update local tlb */ + pdate_mmu_cache(vma, addr, vmf->pte); ret = false; goto pte_unlock; } @@ -2618,8 +2618,8 @@ static inline void wp_page_reuse(struct vm_fault *vmf) flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); entry = pte_mkyoung(vmf->orig_pte); entry = maybe_mkwrite(pte_mkdirty(entry), vma); - if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1)) - update_mmu_cache(vma, vmf->address, vmf->pte); + ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1); + update_mmu_cache(vma, vmf->address, vmf->pte); pte_unmap_unlock(vmf->pte, vmf->ptl); } @@ -2752,6 +2752,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) new_page = old_page; page_copied = 1; } else { + update_mmu_cache(vma, vmf->address, vmf->pte); mem_cgroup_cancel_charge(new_page, memcg, false); } @@ -2812,6 +2813,7 @@ vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf) * pte_offset_map_lock. */ if (!pte_same(*vmf->pte, vmf->orig_pte)) { + update_mmu_cache(vmf->vma, vmf->address, vmf->pte); pte_unmap_unlock(vmf->pte, vmf->ptl); return VM_FAULT_NOPAGE; } @@ -2936,6 +2938,7 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf) vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl); if (!pte_same(*vmf->pte, vmf->orig_pte)) { + update_mmu_cache(vma, vmf->address, vmf->pte); unlock_page(vmf->page); pte_unmap_unlock(vmf->pte, vmf->ptl); put_page(vmf->page); @@ -3341,8 +3344,10 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf) vma->vm_page_prot)); vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl); - if (!pte_none(*vmf->pte)) + if (!pte_none(*vmf->pte)) { + update_mmu_cache(vma, vmf->address, vmf->pte); goto unlock; + } ret = check_stable_address_space(vma->vm_mm); if (ret) goto unlock; @@ -3378,8 +3383,10 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf) vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl); - if (!pte_none(*vmf->pte)) + if (!pte_none(*vmf->pte)) { + update_mmu_cache(vma, vmf->address, vmf->pte); goto release; + } ret = check_stable_address_space(vma->vm_mm); if (ret) @@ -3646,8 +3653,10 @@ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg, } /* Re-check under ptl */ - if (unlikely(!pte_none(*vmf->pte))) + if (unlikely(!pte_none(*vmf->pte))) { + update_mmu_cache(vma, vmf->address, vmf->pte); return VM_FAULT_NOPAGE; + } flush_icache_page(vma, page); entry = mk_pte(page, vma->vm_page_prot); @@ -4224,18 +4233,18 @@ static vm_fault_t handle_pte_fault(struct vm_fault *vmf) vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd); spin_lock(vmf->ptl); entry = vmf->orig_pte; - if (unlikely(!pte_same(*vmf->pte, entry))) + if (unlikely(!pte_same(*vmf->pte, entry))) { + update_mmu_cache(vmf->vma, vmf->address, vmf->pte); goto unlock; + } if (vmf->flags & FAULT_FLAG_WRITE) { if (!pte_write(entry)) return do_wp_page(vmf); entry = pte_mkdirty(entry); } entry = pte_mkyoung(entry); - if (ptep_set_access_flags(vmf->vma, vmf->address, vmf->pte, entry, + if (!ptep_set_access_flags(vmf->vma, vmf->address, vmf->pte, entry, vmf->flags & FAULT_FLAG_WRITE)) { - update_mmu_cache(vmf->vma, vmf->address, vmf->pte); - } else { /* * This is needed only for protection faults but the arch code * is not yet telling us if this is a protection fault or not. @@ -4245,6 +4254,7 @@ static vm_fault_t handle_pte_fault(struct vm_fault *vmf) if (vmf->flags & FAULT_FLAG_WRITE) flush_tlb_fix_spurious_fault(vmf->vma, vmf->address); } + update_mmu_cache(vmf->vma, vmf->address, vmf->pte); unlock: pte_unmap_unlock(vmf->pte, vmf->ptl); return 0; -- 1.8.3.1