[01/26] mm: Do page fault accounting in handle_mm_fault

Message ID	20200626223130.199227-2-peterx@redhat.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <SRS0=/w+2=AH=kvack.org=owner-linux-mm@kernel.org> DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BA4802088E From: Peter Xu <peterx@redhat.com> To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Andrew Morton <akpm@linux-foundation.org>, Linus Torvalds <torvalds@linux-foundation.org>, Gerald Schaefer <gerald.schaefer@de.ibm.com>, Andrea Arcangeli <aarcange@redhat.com>, Will Deacon <will@kernel.org>, peterx@redhat.com, Michael Ellerman <mpe@ellerman.id.au> Subject: [PATCH 01/26] mm: Do page fault accounting in handle_mm_fault Date: Fri, 26 Jun 2020 18:31:05 -0400 Message-Id: <20200626223130.199227-2-peterx@redhat.com> In-Reply-To: <20200626223130.199227-1-peterx@redhat.com> References: <20200626223130.199227-1-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org Precedence: bulk
Series	mm: Page fault accounting cleanups \| expand [00/26] mm: Page fault accounting cleanups [01/26] mm: Do page fault accounting in handle_mm_fault [02/26] mm/alpha: Use general page fault accounting [03/26] mm/arc: Use general page fault accounting [04/26] mm/arm: Use general page fault accounting [05/26] mm/arm64: Use general page fault accounting [06/26] mm/csky: Use general page fault accounting [07/26] mm/hexagon: Use general page fault accounting [08/26] mm/ia64: Use general page fault accounting [09/26] mm/m68k: Use general page fault accounting [10/26] mm/microblaze: Use general page fault accounting [11/26] mm/mips: Use general page fault accounting [12/26] mm/nds32: Use general page fault accounting [13/26] mm/nios2: Use general page fault accounting [14/26] mm/openrisc: Use general page fault accounting [15/26] mm/parisc: Use general page fault accounting [16/26] mm/powerpc: Use general page fault accounting [17/26] mm/riscv: Use general page fault accounting [18/26] mm/s390: Use general page fault accounting [19/26] mm/sh: Use general page fault accounting [20/26] mm/sparc32: Use general page fault accounting [21/26] mm/sparc64: Use general page fault accounting [22/26] mm/unicore32: Use general page fault accounting [23/26] mm/x86: Use general page fault accounting [24/26] mm/xtensa: Use general page fault accounting [25/26] mm: Clean up the last pieces of page fault accountings [26/26] mm/gup: Remove task_struct pointer for all gup code

diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c index c2d7b6d7bac7..82e72f24486e 100644 --- a/arch/alpha/mm/fault.c +++ b/arch/alpha/mm/fault.c @@ -148,7 +148,7 @@ do_page_fault(unsigned long address, unsigned long mmcsr, /* If for any reason at all we couldn't handle the fault, make sure we exit gracefully rather than endlessly redo the fault. */ - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); if (fault_signal_pending(fault, regs)) return; diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c index 92b339c7adba..34380139e7a2 100644 --- a/arch/arc/mm/fault.c +++ b/arch/arc/mm/fault.c @@ -131,7 +131,7 @@ void do_page_fault(unsigned long address, struct pt_regs *regs) goto bad_area; } - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); /* Quick path to respond to signals */ if (fault_signal_pending(fault, regs)) { diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c index 2dd5c41cbb8d..0d6be0f4f27c 100644 --- a/arch/arm/mm/fault.c +++ b/arch/arm/mm/fault.c @@ -223,7 +223,7 @@ __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr, goto out; } - return handle_mm_fault(vma, addr & PAGE_MASK, flags); + return handle_mm_fault(vma, addr & PAGE_MASK, flags, NULL); check_stack: /* Don't allow expansion below FIRST_USER_ADDRESS */ diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index c9cedc0432d2..5f6607b951b8 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -422,7 +422,7 @@ static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr, */ if (!(vma->vm_flags & vm_flags)) return VM_FAULT_BADACCESS; - return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags); + return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags, NULL); } static bool is_el0_instruction_abort(unsigned int esr) diff --git a/arch/csky/mm/fault.c b/arch/csky/mm/fault.c index 4e6dc68f3258..b14f97d3cb15 100644 --- a/arch/csky/mm/fault.c +++ b/arch/csky/mm/fault.c @@ -150,7 +150,8 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write, * make sure we exit gracefully rather than endlessly redo * the fault. */ - fault = handle_mm_fault(vma, address, write ? FAULT_FLAG_WRITE : 0); + fault = handle_mm_fault(vma, address, write ? FAULT_FLAG_WRITE : 0, + NULL); if (unlikely(fault & VM_FAULT_ERROR)) { if (fault & VM_FAULT_OOM) goto out_of_memory; diff --git a/arch/hexagon/mm/vm_fault.c b/arch/hexagon/mm/vm_fault.c index 72334b26317a..f04cd0a6d905 100644 --- a/arch/hexagon/mm/vm_fault.c +++ b/arch/hexagon/mm/vm_fault.c @@ -89,7 +89,7 @@ void do_page_fault(unsigned long address, long cause, struct pt_regs *regs) break; } - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); if (fault_signal_pending(fault, regs)) return; diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c index 30d0c1fca99e..caa93e083c9d 100644 --- a/arch/ia64/mm/fault.c +++ b/arch/ia64/mm/fault.c @@ -139,7 +139,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re * sure we exit gracefully rather than endlessly redo the * fault. */ - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); if (fault_signal_pending(fault, regs)) return; diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c index 3bfb5c8ac3c7..2db38dfbc00c 100644 --- a/arch/m68k/mm/fault.c +++ b/arch/m68k/mm/fault.c @@ -135,7 +135,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, * the fault. */ - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); pr_debug("handle_mm_fault returns %x\n", fault); if (fault_signal_pending(fault, regs)) diff --git a/arch/microblaze/mm/fault.c b/arch/microblaze/mm/fault.c index 3248141f8ed5..9abfa5224386 100644 --- a/arch/microblaze/mm/fault.c +++ b/arch/microblaze/mm/fault.c @@ -215,7 +215,7 @@ void do_page_fault(struct pt_regs *regs, unsigned long address, * make sure we exit gracefully rather than endlessly redo * the fault. */ - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); if (fault_signal_pending(fault, regs)) return; diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c index f8d62cd83b36..31c2afb8f8a5 100644 --- a/arch/mips/mm/fault.c +++ b/arch/mips/mm/fault.c @@ -152,7 +152,7 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write, * make sure we exit gracefully rather than endlessly redo * the fault. */ - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); if (fault_signal_pending(fault, regs)) return; diff --git a/arch/nds32/mm/fault.c b/arch/nds32/mm/fault.c index f331e533edc2..22527129025c 100644 --- a/arch/nds32/mm/fault.c +++ b/arch/nds32/mm/fault.c @@ -207,7 +207,7 @@ void do_page_fault(unsigned long entry, unsigned long addr, * the fault. */ - fault = handle_mm_fault(vma, addr, flags); + fault = handle_mm_fault(vma, addr, flags, NULL); /* * If we need to retry but a fatal signal is pending, handle the diff --git a/arch/nios2/mm/fault.c b/arch/nios2/mm/fault.c index ec9d8a9c426f..88abf297c759 100644 --- a/arch/nios2/mm/fault.c +++ b/arch/nios2/mm/fault.c @@ -131,7 +131,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long cause, * make sure we exit gracefully rather than endlessly redo * the fault. */ - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); if (fault_signal_pending(fault, regs)) return; diff --git a/arch/openrisc/mm/fault.c b/arch/openrisc/mm/fault.c index 8af1cc78c4fb..45aedc572361 100644 --- a/arch/openrisc/mm/fault.c +++ b/arch/openrisc/mm/fault.c @@ -159,7 +159,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long address, * the fault. */ - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); if (fault_signal_pending(fault, regs)) return; diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c index 86e8c848f3d7..c10908ea8803 100644 --- a/arch/parisc/mm/fault.c +++ b/arch/parisc/mm/fault.c @@ -302,7 +302,7 @@ void do_page_fault(struct pt_regs *regs, unsigned long code, * fault. */ - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); if (fault_signal_pending(fault, regs)) return; diff --git a/arch/powerpc/mm/copro_fault.c b/arch/powerpc/mm/copro_fault.c index beb060b96632..c0478bef1f14 100644 --- a/arch/powerpc/mm/copro_fault.c +++ b/arch/powerpc/mm/copro_fault.c @@ -64,7 +64,7 @@ int copro_handle_mm_fault(struct mm_struct *mm, unsigned long ea, } ret = 0; - *flt = handle_mm_fault(vma, ea, is_write ? FAULT_FLAG_WRITE : 0); + *flt = handle_mm_fault(vma, ea, is_write ? FAULT_FLAG_WRITE : 0, NULL); if (unlikely(*flt & VM_FAULT_ERROR)) { if (*flt & VM_FAULT_OOM) { ret = -ENOMEM; diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 84af6c8eecf7..992b10c3761c 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -563,7 +563,7 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address, * make sure we exit gracefully rather than endlessly redo * the fault. */ - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); #ifdef CONFIG_PPC_MEM_KEYS /* diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c index be84e32adc4c..677ee1bb11ac 100644 --- a/arch/riscv/mm/fault.c +++ b/arch/riscv/mm/fault.c @@ -110,7 +110,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs) * make sure we exit gracefully rather than endlessly redo * the fault. */ - fault = handle_mm_fault(vma, addr, flags); + fault = handle_mm_fault(vma, addr, flags, NULL); /* * If we need to retry but a fatal signal is pending, handle the diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index dedc28be27ab..ab6d7eedcfab 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -479,7 +479,7 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) * make sure we exit gracefully rather than endlessly redo * the fault. */ - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); if (fault_signal_pending(fault, regs)) { fault = VM_FAULT_SIGNAL; if (flags & FAULT_FLAG_RETRY_NOWAIT) diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c index 5f23d7907597..a4e670a9c9b3 100644 --- a/arch/sh/mm/fault.c +++ b/arch/sh/mm/fault.c @@ -464,7 +464,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, * make sure we exit gracefully rather than endlessly redo * the fault. */ - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR))) if (mm_fault_error(regs, error_code, address, fault)) diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c index f6e0e601f857..61524d284706 100644 --- a/arch/sparc/mm/fault_32.c +++ b/arch/sparc/mm/fault_32.c @@ -235,7 +235,7 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write, * make sure we exit gracefully rather than endlessly redo * the fault. */ - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); if (fault_signal_pending(fault, regs)) return; @@ -411,7 +411,7 @@ static void force_user_fault(unsigned long address, int write) if (!(vma->vm_flags & (VM_READ | VM_EXEC))) goto bad_area; } - switch (handle_mm_fault(vma, address, flags)) { + switch (handle_mm_fault(vma, address, flags, NULL)) { case VM_FAULT_SIGBUS: case VM_FAULT_OOM: goto do_sigbus; diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c index c0c0dd471b6b..6b702a0a8155 100644 --- a/arch/sparc/mm/fault_64.c +++ b/arch/sparc/mm/fault_64.c @@ -423,7 +423,7 @@ asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs) goto bad_area; } - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); if (fault_signal_pending(fault, regs)) goto exit_exception; diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c index 8f18cf56b3dd..32cc8f59322b 100644 --- a/arch/um/kernel/trap.c +++ b/arch/um/kernel/trap.c @@ -75,7 +75,7 @@ int handle_page_fault(unsigned long address, unsigned long ip, do { vm_fault_t fault; - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) goto out_nosemaphore; diff --git a/arch/unicore32/mm/fault.c b/arch/unicore32/mm/fault.c index 3022104aa613..847ff24fcc2a 100644 --- a/arch/unicore32/mm/fault.c +++ b/arch/unicore32/mm/fault.c @@ -186,7 +186,7 @@ static vm_fault_t __do_pf(struct mm_struct *mm, unsigned long addr, * If for any reason at all we couldn't handle the fault, make * sure we exit gracefully rather than endlessly redo the fault. */ - fault = handle_mm_fault(vma, addr & PAGE_MASK, flags); + fault = handle_mm_fault(vma, addr & PAGE_MASK, flags, NULL); return fault; check_stack: diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index a51df516b87b..3e27ed85af06 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1461,7 +1461,7 @@ void do_user_addr_fault(struct pt_regs *regs, * userland). The return to userland is identified whenever * FAULT_FLAG_USER|FAULT_FLAG_KILLABLE are both set in flags. */ - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); major |= fault & VM_FAULT_MAJOR; /* Quick path to respond to signals */ diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c index e7172bd53ced..722ef3c98d60 100644 --- a/arch/xtensa/mm/fault.c +++ b/arch/xtensa/mm/fault.c @@ -108,7 +108,7 @@ void do_page_fault(struct pt_regs *regs) * make sure we exit gracefully rather than endlessly redo * the fault. */ - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, NULL); if (fault_signal_pending(fault, regs)) return; diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c index d6d85debd01b..66042b816943 100644 --- a/drivers/iommu/amd_iommu_v2.c +++ b/drivers/iommu/amd_iommu_v2.c @@ -497,7 +497,7 @@ static void do_fault(struct work_struct *work) if (access_error(vma, fault)) goto out; - ret = handle_mm_fault(vma, address, flags); + ret = handle_mm_fault(vma, address, flags, NULL); out: up_read(&mm->mmap_sem); diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c index 2998418f0a38..c9cb5e5b6c34 100644 --- a/drivers/iommu/intel-svm.c +++ b/drivers/iommu/intel-svm.c @@ -629,7 +629,7 @@ static irqreturn_t prq_event_thread(int irq, void *d) goto invalid; ret = handle_mm_fault(vma, address, - req->wr_req ? FAULT_FLAG_WRITE : 0); + req->wr_req ? FAULT_FLAG_WRITE : 0, NULL); if (ret & VM_FAULT_ERROR) goto invalid; diff --git a/include/linux/mm.h b/include/linux/mm.h index f3fe7371855c..46bee4044ac1 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -36,6 +36,7 @@ struct file_ra_state; struct user_struct; struct writeback_control; struct bdi_writeback; +struct pt_regs; void init_mm_internals(void); @@ -1652,7 +1653,8 @@ int invalidate_inode_page(struct page *page); #ifdef CONFIG_MMU extern vm_fault_t handle_mm_fault(struct vm_area_struct *vma, - unsigned long address, unsigned int flags); + unsigned long address, unsigned int flags, + struct pt_regs *regs); extern int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm, unsigned long address, unsigned int fault_flags, bool *unlocked); @@ -1662,7 +1664,8 @@ void unmap_mapping_range(struct address_space *mapping, loff_t const holebegin, loff_t const holelen, int even_cows); #else static inline vm_fault_t handle_mm_fault(struct vm_area_struct *vma, - unsigned long address, unsigned int flags) + unsigned long address, unsigned int flags, + struct pt_regs *regs) { /* should never happen if there's no MMU */ BUG(); diff --git a/mm/gup.c b/mm/gup.c index 87a6a59fe667..1a48c639ea49 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -876,7 +876,7 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma, fault_flags |= FAULT_FLAG_TRIED; } - ret = handle_mm_fault(vma, address, fault_flags); + ret = handle_mm_fault(vma, address, fault_flags, NULL); if (ret & VM_FAULT_ERROR) { int err = vm_fault_to_errno(ret, *flags); @@ -1222,7 +1222,7 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm, fatal_signal_pending(current)) return -EINTR; - ret = handle_mm_fault(vma, address, fault_flags); + ret = handle_mm_fault(vma, address, fault_flags, NULL); major |= ret & VM_FAULT_MAJOR; if (ret & VM_FAULT_ERROR) { int err = vm_fault_to_errno(ret, 0); diff --git a/mm/hmm.c b/mm/hmm.c index 280585833adf..5fca59a1f6e9 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -90,7 +90,8 @@ static int hmm_vma_fault(unsigned long addr, unsigned long end, } for (; addr < end; addr += PAGE_SIZE) - if (handle_mm_fault(vma, addr, fault_flags) & VM_FAULT_ERROR) + if (handle_mm_fault(vma, addr, fault_flags, NULL) & + VM_FAULT_ERROR) return -EFAULT; return -EBUSY; } diff --git a/mm/ksm.c b/mm/ksm.c index 281c00129a2e..2e2b02abcc0f 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -480,7 +480,8 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr) break; if (PageKsm(page)) ret = handle_mm_fault(vma, addr, - FAULT_FLAG_WRITE | FAULT_FLAG_REMOTE); + FAULT_FLAG_WRITE | FAULT_FLAG_REMOTE, + NULL); else ret = VM_FAULT_WRITE; put_page(page); diff --git a/mm/memory.c b/mm/memory.c index f703fe8c8346..4a9b333b079e 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -71,6 +71,8 @@ #include <linux/dax.h> #include <linux/oom.h> #include <linux/numa.h> +#include <linux/perf_event.h> +#include <linux/ptrace.h> #include <trace/events/kmem.h> @@ -4345,6 +4347,36 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, return handle_pte_fault(&vmf); } +/** + * mm_account_fault - Do page fault accountings + * @regs: the pt_regs struct pointer. When set to NULL, will skip accounting + * @address: faulted address. + * @major: whether this is a major fault. + * + * This will take care of most of the page fault accountings. It should only + * be called when a page fault is completed. For example, VM_FAULT_RETRY means + * the fault needs to be retried again later, so it should not contribute to + * the accounting. + * + * The accounting will also include the PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN] + * perf counter updates. Note: the handling of PERF_COUNT_SW_PAGE_FAULTS + * should still be in per-arch page fault handlers at the entry of page fault. + */ +static inline void mm_account_fault(struct pt_regs *regs, + unsigned long address, bool major) +{ + if (!regs) + return; + + if (major) { + current->maj_flt++; + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address); + } else { + current->min_flt++; + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address); + } +} + /* * By the time we get here, we already hold the mm semaphore * @@ -4352,7 +4384,7 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, * return value. See filemap_fault() and __lock_page_or_retry(). */ vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, - unsigned int flags) + unsigned int flags, struct pt_regs *regs) { vm_fault_t ret; @@ -4393,6 +4425,34 @@ vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, mem_cgroup_oom_synchronize(false); } + if (ret & (VM_FAULT_RETRY | VM_FAULT_ERROR)) + return ret; + + /* + * Do accounting in the common code, to avoid unnecessary + * architecture differences or duplicated code. + * + * We arbitrarily make the rules be: + * + * - Unsuccessful faults do not count (e.g. when the address wasn't + * valid). That includes arch_vma_access_permitted() failing above. + * + * So this is expressly not a "this many hardware page faults" + * counter. Use the hw profiling for that. + * + * - Incomplete faults do not count (e.g. RETRY). They will only + * count once completed. + * + * - The fault counts as a "major" fault when the final successful + * fault is VM_FAULT_MAJOR, or if it was a retry (which implies that + * we couldn't handle it immediately previously). + * + * - If the fault is done for GUP, regs will be NULL and no accounting + * will be done. + */ + mm_account_fault(regs, address, (ret & VM_FAULT_MAJOR) || + (flags & FAULT_FLAG_TRIED)); + return ret; } EXPORT_SYMBOL_GPL(handle_mm_fault);

[01/26] mm: Do page fault accounting in handle_mm_fault

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