From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: + mm-arm-use-general-page-fault-accounting.patch added to -mm tree Date: Wed, 08 Jul 2020 17:06:45 -0700 Message-ID: <20200709000645.4hs1HwZ95%akpm@linux-foundation.org> References: <20200703151445.b6a0cfee402c7c5c4651f1b1@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:45888 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725972AbgGIAGq (ORCPT ); Wed, 8 Jul 2020 20:06:46 -0400 In-Reply-To: <20200703151445.b6a0cfee402c7c5c4651f1b1@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: linux@armlinux.org.uk, mm-commits@vger.kernel.org, peterx@redhat.com, will@kernel.org The patch titled Subject: mm/arm: use general page fault accounting has been added to the -mm tree. Its filename is mm-arm-use-general-page-fault-accounting.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-arm-use-general-page-fault-accounting.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-arm-use-general-page-fault-accounting.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Peter Xu Subject: mm/arm: use general page fault accounting Use the general page fault accounting by passing regs into handle_mm_fault(). It naturally solve the issue of multiple page fault accounting when page fault retry happened. To do this, we need to pass the pt_regs pointer into __do_page_fault(). Fix PERF_COUNT_SW_PAGE_FAULTS perf event manually for page fault retries, by moving it before taking mmap_sem. Link: http://lkml.kernel.org/r/20200707225021.200906-5-peterx@redhat.com Signed-off-by: Peter Xu Cc: Russell King Cc: Will Deacon Signed-off-by: Andrew Morton --- arch/arm/mm/fault.c | 25 ++++++------------------- 1 file changed, 6 insertions(+), 19 deletions(-) --- a/arch/arm/mm/fault.c~mm-arm-use-general-page-fault-accounting +++ a/arch/arm/mm/fault.c @@ -202,7 +202,8 @@ static inline bool access_error(unsigned static vm_fault_t __kprobes __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr, - unsigned int flags, struct task_struct *tsk) + unsigned int flags, struct task_struct *tsk, + struct pt_regs *regs) { struct vm_area_struct *vma; vm_fault_t fault; @@ -224,7 +225,7 @@ good_area: goto out; } - return handle_mm_fault(vma, addr & PAGE_MASK, flags, NULL); + return handle_mm_fault(vma, addr & PAGE_MASK, flags, regs); check_stack: /* Don't allow expansion below FIRST_USER_ADDRESS */ @@ -266,6 +267,8 @@ do_page_fault(unsigned long addr, unsign if ((fsr & FSR_WRITE) && !(fsr & FSR_CM)) flags |= FAULT_FLAG_WRITE; + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr); + /* * As per x86, we may deadlock here. However, since the kernel only * validly references user space from well defined areas of the code, @@ -290,7 +293,7 @@ retry: #endif } - fault = __do_page_fault(mm, addr, fsr, flags, tsk); + fault = __do_page_fault(mm, addr, fsr, flags, tsk, regs); /* If we need to retry but a fatal signal is pending, handle the * signal first. We do not need to release the mmap_lock because @@ -302,23 +305,7 @@ retry: return 0; } - /* - * Major/minor page fault accounting is only done on the - * initial attempt. If we go through a retry, it is extremely - * likely that the page will be found in page cache at that point. - */ - - perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr); if (!(fault & VM_FAULT_ERROR) && flags & FAULT_FLAG_ALLOW_RETRY) { - if (fault & VM_FAULT_MAJOR) { - tsk->maj_flt++; - perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, - regs, addr); - } else { - tsk->min_flt++; - perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, - regs, addr); - } if (fault & VM_FAULT_RETRY) { flags |= FAULT_FLAG_TRIED; goto retry; _ Patches currently in -mm which might be from peterx@redhat.com are mm-do-page-fault-accounting-in-handle_mm_fault.patch mm-alpha-use-general-page-fault-accounting.patch mm-arc-use-general-page-fault-accounting.patch mm-arm-use-general-page-fault-accounting.patch mm-arm64-use-general-page-fault-accounting.patch mm-csky-use-general-page-fault-accounting.patch mm-hexagon-use-general-page-fault-accounting.patch mm-ia64-use-general-page-fault-accounting.patch mm-m68k-use-general-page-fault-accounting.patch mm-microblaze-use-general-page-fault-accounting.patch mm-mips-use-general-page-fault-accounting.patch mm-nds32-use-general-page-fault-accounting.patch mm-nios2-use-general-page-fault-accounting.patch mm-openrisc-use-general-page-fault-accounting.patch mm-parisc-use-general-page-fault-accounting.patch mm-powerpc-use-general-page-fault-accounting.patch mm-riscv-use-general-page-fault-accounting.patch mm-s390-use-general-page-fault-accounting.patch mm-sh-use-general-page-fault-accounting.patch mm-sparc32-use-general-page-fault-accounting.patch mm-sparc64-use-general-page-fault-accounting.patch mm-x86-use-general-page-fault-accounting.patch mm-xtensa-use-general-page-fault-accounting.patch mm-clean-up-the-last-pieces-of-page-fault-accountings.patch mm-gup-remove-task_struct-pointer-for-all-gup-code.patch