From patchwork Thu May 21 03:30:34 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: bibo mao X-Patchwork-Id: 11562133 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AA074159A for ; Thu, 21 May 2020 03:31:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 98DBD207FB for ; Thu, 21 May 2020 03:31:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728178AbgEUDbC (ORCPT ); Wed, 20 May 2020 23:31:02 -0400 Received: from mail.loongson.cn ([114.242.206.163]:60932 "EHLO loongson.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728172AbgEUDbC (ORCPT ); Wed, 20 May 2020 23:31:02 -0400 Received: from kvm-dev1.localdomain (unknown [10.2.5.134]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9Dx793d9cVewz03AA--.629S2; Thu, 21 May 2020 11:30:37 +0800 (CST) From: Bibo Mao To: Thomas Bogendoerfer , Jiaxun Yang , Huacai Chen , Andrew Morton , Paul Burton , Dmitry Korotin , =?utf-8?q?Philippe_Mathieu-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, David Hildenbrand Subject: [PATCH v5 1/4] MIPS: Do not flush tlb page when updating PTE entry Date: Thu, 21 May 2020 11:30:34 +0800 Message-Id: <1590031837-9582-1-git-send-email-maobibo@loongson.cn> X-Mailer: git-send-email 1.8.3.1 X-CM-TRANSID: AQAAf9Dx793d9cVewz03AA--.629S2 X-Coremail-Antispam: 1UD129KBjvJXoW7uFW3ZryxtrWktFy7GF43GFg_yoW8GFy5pF ZrArykKw4kG3y0yFy8Ar1v9r43J3yDGrZ8KryDCryqv3ZrXF1kKrs3Ka4Iyry8ZFyak3W8 Kr4jqF4DZa12v37anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvvb7Iv0xC_KF4lb4IE77IF4wAFF20E14v26ryj6rWUM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rw A2F7IY1VAKz4vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xII jxv20xvEc7CjxVAFwI0_Cr0_Gr1UM28EF7xvwVC2z280aVAFwI0_Gr1j6F4UJwA2z4x0Y4 vEx4A2jsIEc7CjxVAFwI0_Cr1j6rxdM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVAC Y4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJV W8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka 0xkIwI1lc2xSY4AK6svPMxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI 8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AK xVW8ZVWrXwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI 8IcVCY1x0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_WFyUJVCq3wCI42IY6I8E 87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73Uj IFyTuYvjxU2vPfDUUUU X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org It is not necessary to flush tlb page on all CPUs if suitable PTE entry exists already during page fault handling, just updating TLB is fine. Here redefine flush_tlb_fix_spurious_fault as empty on MIPS system. V5: - Define update_mmu_cache function specified on MIPS platform, and add page fault smp-race stats info V4: - add pte_sw_mkyoung function to implement readable privilege, and this function is only in effect on MIPS system. - add page valid bit judgement in function pte_modify V3: - add detailed changelog, modify typo issue in patch V2 v2: - split flush_tlb_fix_spurious_fault and tlb update into two patches - comments typo modification - separate tlb update and add pte readable privilege into two patches Signed-off-by: Bibo Mao --- arch/mips/include/asm/pgtable.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h index 9b01d2d..0d625c2 100644 --- a/arch/mips/include/asm/pgtable.h +++ b/arch/mips/include/asm/pgtable.h @@ -478,6 +478,8 @@ static inline pgprot_t pgprot_writecombine(pgprot_t _prot) return __pgprot(prot); } +#define flush_tlb_fix_spurious_fault(vma, address) do { } while (0) + /* * Conversion functions: convert a page and protection to a page entry, * and a page entry and page directory to the page they refer to. From patchwork Thu May 21 03:30:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: bibo mao X-Patchwork-Id: 11562137 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 99360739 for ; Thu, 21 May 2020 03:31:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 85816207F9 for ; Thu, 21 May 2020 03:31:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728172AbgEUDbC (ORCPT ); Wed, 20 May 2020 23:31:02 -0400 Received: from mail.loongson.cn ([114.242.206.163]:60938 "EHLO loongson.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728176AbgEUDbC (ORCPT ); Wed, 20 May 2020 23:31:02 -0400 Received: from kvm-dev1.localdomain (unknown [10.2.5.134]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9Dx793d9cVewz03AA--.629S3; Thu, 21 May 2020 11:30:38 +0800 (CST) From: Bibo Mao To: Thomas Bogendoerfer , Jiaxun Yang , Huacai Chen , Andrew Morton , Paul Burton , Dmitry Korotin , =?utf-8?q?Philippe_Mathieu-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, David Hildenbrand Subject: [PATCH v5 2/4] mm/memory.c: Update local TLB if PTE entry exists Date: Thu, 21 May 2020 11:30:35 +0800 Message-Id: <1590031837-9582-2-git-send-email-maobibo@loongson.cn> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1590031837-9582-1-git-send-email-maobibo@loongson.cn> References: <1590031837-9582-1-git-send-email-maobibo@loongson.cn> X-CM-TRANSID: AQAAf9Dx793d9cVewz03AA--.629S3 X-Coremail-Antispam: 1UD129KBjvJXoWxuFW5Cr43CrW8JF18ZFW3trb_yoW7ZryfpF 93Ca9rXF4xXr1kAr4xJw1qvr13Za4rJFWkJr9xKw1FywsIqw1Sgay5G3yFyFWkGr95tanr Jr4jgF4Uua1xuw7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPab7Iv0xC_Kw4lb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI 8067AKxVWUGwA2048vs2IY020Ec7CjxVAFwI0_Gr0_Xr1l8cAvFVAK0II2c7xJM28CjxkF 64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcV CY1x0267AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280 aVCY1x0267AKxVWxJr0_GcWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4 CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvj eVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxw CY02Avz4vE-syl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAq x4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6r W5MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF 7I0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxV WUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxU ygo2UUUUU X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org If two threads concurrently fault at the same address, the thread that won the race updates the PTE and its local TLB. For now, the other thread gives up, simply does nothing, and continues. It could happen that this second thread triggers another fault, whereby it only updates its local TLB while handling the fault. Instead of triggering another fault, let's directly update the local TLB of the second thread. It is only useful to architectures where software can update TLB, it may bring out some negative effect if update_mmu_cache is used for other purpose also. It seldom happens where multiple threads access the same page at the same time, so the negative effect is limited on other arches. With specjvm2008 workload, smp-race pgfault counts is about 3% to 4% of the total pgfault counts by watching /proc/vmstats information Signed-off-by: Bibo Mao --- arch/mips/include/asm/pgtable.h | 20 ++++++++++++++++++++ mm/memory.c | 27 +++++++++++++++++++-------- 2 files changed, 39 insertions(+), 8 deletions(-) diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h index 0d625c2..5f610ec 100644 --- a/arch/mips/include/asm/pgtable.h +++ b/arch/mips/include/asm/pgtable.h @@ -480,6 +480,26 @@ static inline pgprot_t pgprot_writecombine(pgprot_t _prot) #define flush_tlb_fix_spurious_fault(vma, address) do { } while (0) +#define __HAVE_ARCH_PTE_SAME +static inline int pte_same(pte_t pte_a, pte_t pte_b) +{ + return pte_val(pte_a) == pte_val(pte_b); +} + +#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS +static inline int ptep_set_access_flags(struct vm_area_struct *vma, + unsigned long address, pte_t *ptep, + pte_t entry, int dirty) +{ + if (!pte_same(*ptep, entry)) + set_pte_at(vma->vm_mm, address, ptep, entry); + /* + * update_mmu_cache will unconditionally execute, handling both + * the case that the PTE changed and the spurious fault case. + */ + return true; +} + /* * Conversion functions: convert a page and protection to a page entry, * and a page entry and page directory to the page they refer to. diff --git a/mm/memory.c b/mm/memory.c index f703fe8..9e2be4a 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2436,10 +2436,9 @@ 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; } @@ -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 */ + update_mmu_cache(vma, addr, vmf->pte); ret = false; goto pte_unlock; } @@ -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); @@ -4224,8 +4233,10 @@ 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); From patchwork Thu May 21 03:30:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: bibo mao X-Patchwork-Id: 11562139 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 16FCC60D for ; Thu, 21 May 2020 03:31:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0A46320738 for ; Thu, 21 May 2020 03:31:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728193AbgEUDbC (ORCPT ); Wed, 20 May 2020 23:31:02 -0400 Received: from mail.loongson.cn ([114.242.206.163]:60934 "EHLO loongson.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726954AbgEUDbC (ORCPT ); Wed, 20 May 2020 23:31:02 -0400 Received: from kvm-dev1.localdomain (unknown [10.2.5.134]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9Dx793d9cVewz03AA--.629S4; Thu, 21 May 2020 11:30:39 +0800 (CST) From: Bibo Mao To: Thomas Bogendoerfer , Jiaxun Yang , Huacai Chen , Andrew Morton , Paul Burton , Dmitry Korotin , =?utf-8?q?Philippe_Mathieu-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, David Hildenbrand Subject: [PATCH v5 3/4] mm/memory.c: Add memory read privilege on page fault handling Date: Thu, 21 May 2020 11:30:36 +0800 Message-Id: <1590031837-9582-3-git-send-email-maobibo@loongson.cn> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1590031837-9582-1-git-send-email-maobibo@loongson.cn> References: <1590031837-9582-1-git-send-email-maobibo@loongson.cn> X-CM-TRANSID: AQAAf9Dx793d9cVewz03AA--.629S4 X-Coremail-Antispam: 1UD129KBjvJXoWxZFy5KF13KFW5CFy3Gr1rJFb_yoW5AFy7pF Z7CwnY9rsrXw1xAFWfGFn29r1ruw4rKFWY9rySk3Wku3ZxJrn8Wrs7GayFv34kJFWkK3Wr Gr4jqr4UZay2vaUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPSb7Iv0xC_Kw4lb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI 8067AKxVWUXwA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF 64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcV CY1x0267AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280 aVCY1x0267AKxVWxJr0_GcWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4 CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvj eVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxw CY02Avz4vE-syl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAq x4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6r W5MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF 7I0E14v26F4j6r4UJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI 0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7I U5DMa5UUUUU== X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Here add pte_sw_mkyoung function to make page readable on MIPS platform during page fault handling. This patch improves page fault latency about 10% on my MIPS machine with lmbench lat_pagefault case. It is noop function on other arches, there is no negative influence on those architectures. Signed-off-by: Bibo Mao --- arch/mips/include/asm/pgtable.h | 2 ++ include/asm-generic/pgtable.h | 16 ++++++++++++++++ mm/memory.c | 3 +++ 3 files changed, 21 insertions(+) diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h index 5f610ec..9cd811e 100644 --- a/arch/mips/include/asm/pgtable.h +++ b/arch/mips/include/asm/pgtable.h @@ -414,6 +414,8 @@ static inline pte_t pte_mkyoung(pte_t pte) return pte; } +#define pte_sw_mkyoung pte_mkyoung + #ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT static inline int pte_huge(pte_t pte) { return pte_val(pte) & _PAGE_HUGE; } diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index 329b8c8..7dcfa30 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -227,6 +227,22 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres } #endif +/* + * On some architectures hardware does not set page access bit when accessing + * memory page, it is responsibilty of software setting this bit. It brings + * out extra page fault penalty to track page access bit. For optimization page + * access bit can be set during all page fault flow on these arches. + * To be differentiate with macro pte_mkyoung, this macro is used on platforms + * where software maintains page access bit. + */ +#ifndef pte_sw_mkyoung +static inline pte_t pte_sw_mkyoung(pte_t pte) +{ + return pte; +} +#define pte_sw_mkyoung pte_sw_mkyoung +#endif + #ifndef pte_savedwrite #define pte_savedwrite pte_write #endif diff --git a/mm/memory.c b/mm/memory.c index 9e2be4a..33d3b4c 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2704,6 +2704,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) } flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); entry = mk_pte(new_page, vma->vm_page_prot); + entry = pte_sw_mkyoung(entry); entry = maybe_mkwrite(pte_mkdirty(entry), vma); /* * Clear the pte entry and flush it first, before updating the @@ -3378,6 +3379,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf) __SetPageUptodate(page); entry = mk_pte(page, vma->vm_page_prot); + entry = pte_sw_mkyoung(entry); if (vma->vm_flags & VM_WRITE) entry = pte_mkwrite(pte_mkdirty(entry)); @@ -3660,6 +3662,7 @@ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg, flush_icache_page(vma, page); entry = mk_pte(page, vma->vm_page_prot); + entry = pte_sw_mkyoung(entry); if (write) entry = maybe_mkwrite(pte_mkdirty(entry), vma); /* copy-on-write page */ From patchwork Thu May 21 03:30:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: bibo mao X-Patchwork-Id: 11562135 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 21211739 for ; Thu, 21 May 2020 03:31:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 141492078B for ; Thu, 21 May 2020 03:31:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728243AbgEUDbF (ORCPT ); Wed, 20 May 2020 23:31:05 -0400 Received: from mail.loongson.cn ([114.242.206.163]:60956 "EHLO loongson.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728176AbgEUDbF (ORCPT ); Wed, 20 May 2020 23:31:05 -0400 Received: from kvm-dev1.localdomain (unknown [10.2.5.134]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9Dx793d9cVewz03AA--.629S5; Thu, 21 May 2020 11:30:39 +0800 (CST) From: Bibo Mao To: Thomas Bogendoerfer , Jiaxun Yang , Huacai Chen , Andrew Morton , Paul Burton , Dmitry Korotin , =?utf-8?q?Philippe_Mathieu-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, David Hildenbrand Subject: [PATCH v5 4/4] MIPS: mm: add page valid judgement in function pte_modify Date: Thu, 21 May 2020 11:30:37 +0800 Message-Id: <1590031837-9582-4-git-send-email-maobibo@loongson.cn> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1590031837-9582-1-git-send-email-maobibo@loongson.cn> References: <1590031837-9582-1-git-send-email-maobibo@loongson.cn> X-CM-TRANSID: AQAAf9Dx793d9cVewz03AA--.629S5 X-Coremail-Antispam: 1UD129KBjvdXoWrtFW8AryxtFWfuw43ur4DJwb_yoWDWwbEkw 47Zw4fCr95JF47uFW7A3WrJry2ga48uw1qva4xJw1ayF1qgr45CFW8WryUArZ8uFsFyF40 qa95G34fCFsrKjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbg8YjsxI4VWxJwAYFVCjjxCrM7AC8VAFwI0_Wr0E3s1l1xkIjI8I 6I8E6xAIw20EY4v20xvaj40_Wr0E3s1l1IIY67AEw4v_Jr0_Jr4l82xGYIkIc2x26280x7 IE14v26r1rM28IrcIa0xkI8VCY1x0267AKxVW5JVCq3wA2ocxC64kIII0Yj41l84x0c7CE w4AK67xGY2AK021l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6x kF7I0E14v26r4UJVWxJr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280 aVCY1x0267AKxVWxJr0_GcWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4 CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvj eVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxw CY02Avz4vE-syl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAq x4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6r W5MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF 7I0E14v26F4j6r4UJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI 0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7I U8FD73UUUUU== X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org If original PTE has _PAGE_ACCESSED bit set, and new pte has no _PAGE_NO_READ bit set, we can add _PAGE_SILENT_READ bit to enable page valid bit. Signed-off-by: Bibo Mao --- arch/mips/include/asm/pgtable.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h index 9cd811e..ef26552 100644 --- a/arch/mips/include/asm/pgtable.h +++ b/arch/mips/include/asm/pgtable.h @@ -529,8 +529,11 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) #else static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) { - return __pte((pte_val(pte) & _PAGE_CHG_MASK) | - (pgprot_val(newprot) & ~_PAGE_CHG_MASK)); + pte_val(pte) &= _PAGE_CHG_MASK; + pte_val(pte) |= pgprot_val(newprot) & ~_PAGE_CHG_MASK; + if ((pte_val(pte) & _PAGE_ACCESSED) && !(pte_val(pte) & _PAGE_NO_READ)) + pte_val(pte) |= _PAGE_SILENT_READ; + return pte; } #endif