From: Laurent Dufour <ldufour@linux.vnet.ibm.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: paulmck@linux.vnet.ibm.com, peterz@infradead.org,
akpm@linux-foundation.org, kirill@shutemov.name,
ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net,
jack@suse.cz, benh@kernel.crashing.org, mpe@ellerman.id.au,
paulus@samba.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
hpa@zytor.com, Will Deacon <will.deacon@arm.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
kemi.wang@intel.com, sergey.senozhatsky.work@gmail.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com,
npiggin@gmail.com, bsingharora@gmail.com,
Tim Chen <tim.c.chen@linux.intel.com>,
linuxppc-dev@lists.ozlabs.org, x86@kernel.org
Subject: Re: [PATCH v6 22/24] mm: Speculative page fault handler return VMA
Date: Tue, 16 Jan 2018 15:47:51 +0100 [thread overview]
Message-ID: <6d958348-bece-2c21-e8dc-4e5a65e82f9b@linux.vnet.ibm.com> (raw)
In-Reply-To: <20180113042354.GA24241@bombadil.infradead.org>
On 13/01/2018 05:23, Matthew Wilcox wrote:
> On Fri, Jan 12, 2018 at 11:02:51AM -0800, Matthew Wilcox wrote:
>> On Fri, Jan 12, 2018 at 06:26:06PM +0100, Laurent Dufour wrote:
>>> @@ -1354,7 +1354,10 @@ extern int handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
>>> unsigned int flags);
>>> #ifdef CONFIG_SPF
>>> extern int handle_speculative_fault(struct mm_struct *mm,
>>> + unsigned long address, unsigned int flags,
>>> + struct vm_area_struct **vma);
>>
>> I think this shows that we need to create 'struct vm_fault' on the stack
>> in the arch code and then pass it to handle_speculative_fault(), followed
>> by handle_mm_fault(). That should be quite a nice cleanup actually.
>> I know that's only 30+ architectures to change ;-)
>
> Of course, we don't need to change them all. Try this:
That would be good candidate for a clean up but I'm not sure this should be
part of this already too long series.
If you don't mind, unless a global agreement is stated on that, I'd prefer
to postpone such a change once the initial series is accepted.
Cheers,
Laurent.
> Subject: [PATCH] Add vm_handle_fault
>
> For the speculative fault handler, we want to create the struct vm_fault
> on the stack in the arch code and pass it into the generic mm code.
> To avoid changing 30+ architectures, leave handle_mm_fault with its
> current function signature and move its guts into the new vm_handle_fault
> function. Even this saves a nice 172 bytes on the random x86-64 .config
> I happen to have around.
>
> Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 5eb3d2524bdc..403934297a3d 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -3977,36 +3977,28 @@ static int handle_pte_fault(struct vm_fault *vmf)
> * The mmap_sem may have been released depending on flags and our
> * return value. See filemap_fault() and __lock_page_or_retry().
> */
> -static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
> - unsigned int flags)
> +static int __handle_mm_fault(struct vm_fault *vmf)
> {
> - struct vm_fault vmf = {
> - .vma = vma,
> - .address = address & PAGE_MASK,
> - .flags = flags,
> - .pgoff = linear_page_index(vma, address),
> - .gfp_mask = __get_fault_gfp_mask(vma),
> - };
> - unsigned int dirty = flags & FAULT_FLAG_WRITE;
> - struct mm_struct *mm = vma->vm_mm;
> + unsigned int dirty = vmf->flags & FAULT_FLAG_WRITE;
> + struct mm_struct *mm = vmf->vma->vm_mm;
> pgd_t *pgd;
> p4d_t *p4d;
> int ret;
>
> - pgd = pgd_offset(mm, address);
> - p4d = p4d_alloc(mm, pgd, address);
> + pgd = pgd_offset(mm, vmf->address);
> + p4d = p4d_alloc(mm, pgd, vmf->address);
> if (!p4d)
> return VM_FAULT_OOM;
>
> - vmf.pud = pud_alloc(mm, p4d, address);
> - if (!vmf.pud)
> + vmf->pud = pud_alloc(mm, p4d, vmf->address);
> + if (!vmf->pud)
> return VM_FAULT_OOM;
> - if (pud_none(*vmf.pud) && transparent_hugepage_enabled(vma)) {
> - ret = create_huge_pud(&vmf);
> + if (pud_none(*vmf->pud) && transparent_hugepage_enabled(vmf->vma)) {
> + ret = create_huge_pud(vmf);
> if (!(ret & VM_FAULT_FALLBACK))
> return ret;
> } else {
> - pud_t orig_pud = *vmf.pud;
> + pud_t orig_pud = *vmf->pud;
>
> barrier();
> if (pud_trans_huge(orig_pud) || pud_devmap(orig_pud)) {
> @@ -4014,50 +4006,51 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
> /* NUMA case for anonymous PUDs would go here */
>
> if (dirty && !pud_access_permitted(orig_pud, WRITE)) {
> - ret = wp_huge_pud(&vmf, orig_pud);
> + ret = wp_huge_pud(vmf, orig_pud);
> if (!(ret & VM_FAULT_FALLBACK))
> return ret;
> } else {
> - huge_pud_set_accessed(&vmf, orig_pud);
> + huge_pud_set_accessed(vmf, orig_pud);
> return 0;
> }
> }
> }
>
> - vmf.pmd = pmd_alloc(mm, vmf.pud, address);
> - if (!vmf.pmd)
> + vmf->pmd = pmd_alloc(mm, vmf->pud, vmf->address);
> + if (!vmf->pmd)
> return VM_FAULT_OOM;
> - if (pmd_none(*vmf.pmd) && transparent_hugepage_enabled(vma)) {
> - ret = create_huge_pmd(&vmf);
> + if (pmd_none(*vmf->pmd) && transparent_hugepage_enabled(vmf->vma)) {
> + ret = create_huge_pmd(vmf);
> if (!(ret & VM_FAULT_FALLBACK))
> return ret;
> } else {
> - pmd_t orig_pmd = *vmf.pmd;
> + pmd_t orig_pmd = *vmf->pmd;
>
> barrier();
> if (unlikely(is_swap_pmd(orig_pmd))) {
> VM_BUG_ON(thp_migration_supported() &&
> !is_pmd_migration_entry(orig_pmd));
> if (is_pmd_migration_entry(orig_pmd))
> - pmd_migration_entry_wait(mm, vmf.pmd);
> + pmd_migration_entry_wait(mm, vmf->pmd);
> return 0;
> }
> if (pmd_trans_huge(orig_pmd) || pmd_devmap(orig_pmd)) {
> - if (pmd_protnone(orig_pmd) && vma_is_accessible(vma))
> - return do_huge_pmd_numa_page(&vmf, orig_pmd);
> + if (pmd_protnone(orig_pmd) &&
> + vma_is_accessible(vmf->vma))
> + return do_huge_pmd_numa_page(vmf, orig_pmd);
>
> if (dirty && !pmd_access_permitted(orig_pmd, WRITE)) {
> - ret = wp_huge_pmd(&vmf, orig_pmd);
> + ret = wp_huge_pmd(vmf, orig_pmd);
> if (!(ret & VM_FAULT_FALLBACK))
> return ret;
> } else {
> - huge_pmd_set_accessed(&vmf, orig_pmd);
> + huge_pmd_set_accessed(vmf, orig_pmd);
> return 0;
> }
> }
> }
>
> - return handle_pte_fault(&vmf);
> + return handle_pte_fault(vmf);
> }
>
> /*
> @@ -4066,9 +4059,10 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
> * The mmap_sem may have been released depending on flags and our
> * return value. See filemap_fault() and __lock_page_or_retry().
> */
> -int handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
> - unsigned int flags)
> +int vm_handle_fault(struct vm_fault *vmf)
> {
> + unsigned int flags = vmf->flags;
> + struct vm_area_struct *vma = vmf->vma;
> int ret;
>
> __set_current_state(TASK_RUNNING);
> @@ -4092,9 +4086,9 @@ int handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
> mem_cgroup_oom_enable();
>
> if (unlikely(is_vm_hugetlb_page(vma)))
> - ret = hugetlb_fault(vma->vm_mm, vma, address, flags);
> + ret = hugetlb_fault(vma->vm_mm, vma, vmf->address, flags);
> else
> - ret = __handle_mm_fault(vma, address, flags);
> + ret = __handle_mm_fault(vmf);
>
> if (flags & FAULT_FLAG_USER) {
> mem_cgroup_oom_disable();
> @@ -4110,6 +4104,26 @@ int handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
>
> return ret;
> }
> +
> +/*
> + * By the time we get here, we already hold the mm semaphore
> + *
> + * The mmap_sem may have been released depending on flags and our
> + * return value. See filemap_fault() and __lock_page_or_retry().
> + */
> +int handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
> + unsigned int flags)
> +{
> + struct vm_fault vmf = {
> + .vma = vma,
> + .address = address & PAGE_MASK,
> + .flags = flags,
> + .pgoff = linear_page_index(vma, address),
> + .gfp_mask = __get_fault_gfp_mask(vma),
> + };
> +
> + return vm_handle_fault(&vmf);
> +}
> EXPORT_SYMBOL_GPL(handle_mm_fault);
>
> #ifndef __PAGETABLE_P4D_FOLDED
>
next prev parent reply other threads:[~2018-01-16 14:48 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-12 17:25 [PATCH v6 00/24] Speculative page faults Laurent Dufour
2018-01-12 17:25 ` [PATCH v6 01/24] x86/mm: Define CONFIG_SPF Laurent Dufour
2018-01-12 18:57 ` Thomas Gleixner
2018-01-15 17:37 ` Laurent Dufour
2018-01-15 17:49 ` Thomas Gleixner
2018-01-15 18:37 ` Laurent Dufour
2018-01-12 17:25 ` [PATCH v6 02/24] powerpc/mm: " Laurent Dufour
2018-01-12 17:25 ` [PATCH v6 03/24] mm: Dont assume page-table invariance during faults Laurent Dufour
2018-01-17 3:04 ` Andi Kleen
2018-01-17 8:57 ` Laurent Dufour
2018-01-12 17:25 ` [PATCH v6 04/24] mm: Prepare for FAULT_FLAG_SPECULATIVE Laurent Dufour
2018-01-12 17:25 ` [PATCH v6 05/24] mm: Introduce pte_spinlock " Laurent Dufour
2018-01-12 17:25 ` [PATCH v6 06/24] mm: VMA sequence count Laurent Dufour
2018-01-12 17:25 ` [PATCH v6 07/24] mm: Protect VMA modifications using " Laurent Dufour
2018-01-12 17:25 ` [PATCH v6 08/24] mm: protect mremap() against SPF hanlder Laurent Dufour
2018-01-12 17:25 ` [PATCH v6 09/24] mm: Protect SPF handler against anon_vma changes Laurent Dufour
2018-01-12 17:25 ` [PATCH v6 10/24] mm: Cache some VMA fields in the vm_fault structure Laurent Dufour
2018-01-12 17:25 ` [PATCH v6 11/24] mm/migrate: Pass vm_fault pointer to migrate_misplaced_page() Laurent Dufour
2018-01-12 17:25 ` [PATCH v6 12/24] mm: Introduce __lru_cache_add_active_or_unevictable Laurent Dufour
2018-01-12 17:25 ` [PATCH v6 13/24] mm: Introduce __maybe_mkwrite() Laurent Dufour
2018-01-12 17:25 ` [PATCH v6 14/24] mm: Introduce __vm_normal_page() Laurent Dufour
2018-01-12 17:25 ` [PATCH v6 15/24] mm: Introduce __page_add_new_anon_rmap() Laurent Dufour
2018-01-12 17:26 ` [PATCH v6 16/24] mm: Protect mm_rb tree with a rwlock Laurent Dufour
2018-01-12 18:48 ` Matthew Wilcox
2018-01-15 17:42 ` Laurent Dufour
2018-01-12 17:26 ` [PATCH v6 17/24] mm: Provide speculative fault infrastructure Laurent Dufour
2018-01-12 17:26 ` [PATCH v6 18/24] mm: Try spin lock in speculative path Laurent Dufour
2018-01-12 18:18 ` Matthew Wilcox
2018-01-16 13:24 ` Laurent Dufour
2018-01-12 17:26 ` [PATCH v6 19/24] mm: Adding speculative page fault failure trace events Laurent Dufour
2018-01-12 17:26 ` [PATCH v6 20/24] perf: Add a speculative page fault sw event Laurent Dufour
2018-01-12 17:26 ` [PATCH v6 21/24] perf tools: Add support for the SPF perf event Laurent Dufour
2018-01-12 17:26 ` [PATCH v6 22/24] mm: Speculative page fault handler return VMA Laurent Dufour
2018-01-12 19:02 ` Matthew Wilcox
2018-01-13 4:23 ` Matthew Wilcox
2018-01-16 14:47 ` Laurent Dufour [this message]
2018-01-16 14:58 ` Matthew Wilcox
2018-01-12 17:26 ` [PATCH v6 23/24] x86/mm: Add speculative pagefault handling Laurent Dufour
2018-01-12 17:26 ` [PATCH v6 24/24] powerpc/mm: Add speculative page fault Laurent Dufour
2018-01-16 15:11 ` [PATCH v6 00/24] Speculative page faults Kirill A. Shutemov
2018-01-17 15:15 ` Laurent Dufour
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