From: Joao Martins <joao.m.martins@oracle.com>
To: linux-mm@kvack.org
Cc: Dan Williams <dan.j.williams@intel.com>,
Vishal Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
Naoya Horiguchi <naoya.horiguchi@nec.com>,
Matthew Wilcox <willy@infradead.org>,
Jason Gunthorpe <jgg@ziepe.ca>,
John Hubbard <jhubbard@nvidia.com>,
Jane Chu <jane.chu@oracle.com>,
Muchun Song <songmuchun@bytedance.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jonathan Corbet <corbet@lwn.net>, Christoph Hellwig <hch@lst.de>,
nvdimm@lists.linux.dev, linux-doc@vger.kernel.org
Subject: Re: [PATCH v6 09/10] device-dax: set mapping prior to vmf_insert_pfn{,_pmd,pud}()
Date: Thu, 25 Nov 2021 11:42:22 +0000 [thread overview]
Message-ID: <0439eb48-1688-a4f4-5feb-8eb2680d652f@oracle.com> (raw)
In-Reply-To: <20211124191005.20783-10-joao.m.martins@oracle.com>
On 11/24/21 19:10, Joao Martins wrote:
> Normally, the @page mapping is set prior to inserting the page into a
> page table entry. Make device-dax adhere to the same ordering, rather
> than setting mapping after the PTE is inserted.
>
> The address_space never changes and it is always associated with the
> same inode and underlying pages. So, the page mapping is set once but
> cleared when the struct pages are removed/freed (i.e. after
> {devm_}memunmap_pages()).
>
> Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> ---
> drivers/dax/device.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dax/device.c b/drivers/dax/device.c
> index 9c87927d4bc2..0ef9fecec005 100644
> --- a/drivers/dax/device.c
> +++ b/drivers/dax/device.c
> @@ -121,6 +121,8 @@ static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
>
> *pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
>
> + dax_set_mapping(vmf, *pfn, fault_size);
> +
> return vmf_insert_mixed(vmf->vma, vmf->address, *pfn);
> }
>
> @@ -161,6 +163,8 @@ static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
>
> *pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
>
> + dax_set_mapping(vmf, *pfn, fault_size);
> +
> return vmf_insert_pfn_pmd(vmf, *pfn, vmf->flags & FAULT_FLAG_WRITE);
> }
>
> @@ -203,6 +207,8 @@ static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
>
> *pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
>
> + dax_set_mapping(vmf, *pfn, fault_size);
> +
> return vmf_insert_pfn_pud(vmf, *pfn, vmf->flags & FAULT_FLAG_WRITE);
> }
> #else
> @@ -245,8 +251,6 @@ static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
> rc = VM_FAULT_SIGBUS;
> }
>
> - if (rc == VM_FAULT_NOPAGE)
> - dax_set_mapping(vmf, pfn, fault_size);
> dax_read_unlock(id);
>
> return rc;
>
This last chunk is going to spoof out a new warning because @fault_size in
dev_dax_huge_fault stops being used after this patch.
I've added below chunk for the next version (in addition to Christoph comments in
patch 4):
@@ -217,7 +223,6 @@ static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
enum page_entry_size pe_size)
{
struct file *filp = vmf->vma->vm_file;
- unsigned long fault_size;
vm_fault_t rc = VM_FAULT_SIGBUS;
int id;
pfn_t pfn;
@@ -230,23 +235,18 @@ static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
id = dax_read_lock();
switch (pe_size) {
case PE_SIZE_PTE:
- fault_size = PAGE_SIZE;
rc = __dev_dax_pte_fault(dev_dax, vmf, &pfn);
break;
case PE_SIZE_PMD:
- fault_size = PMD_SIZE;
rc = __dev_dax_pmd_fault(dev_dax, vmf, &pfn);
break;
case PE_SIZE_PUD:
- fault_size = PUD_SIZE;
rc = __dev_dax_pud_fault(dev_dax, vmf, &pfn);
break;
default:
rc = VM_FAULT_SIGBUS;
}
next prev parent reply other threads:[~2021-11-25 11:42 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-24 19:09 [PATCH v6 00/10] mm, device-dax: Introduce compound pages in devmap Joao Martins
2021-11-24 19:09 ` [PATCH v6 01/10] memory-failure: fetch compound_head after pgmap_pfn_valid() Joao Martins
2021-11-24 19:09 ` [PATCH v6 02/10] mm/page_alloc: split prep_compound_page into head and tail subparts Joao Martins
2021-11-24 19:09 ` [PATCH v6 03/10] mm/page_alloc: refactor memmap_init_zone_device() page init Joao Martins
2021-11-24 19:09 ` [PATCH v6 04/10] mm/memremap: add ZONE_DEVICE support for compound pages Joao Martins
2021-11-25 6:11 ` Christoph Hellwig
2021-11-25 11:35 ` Joao Martins
2021-11-24 19:10 ` [PATCH v6 05/10] device-dax: use ALIGN() for determining pgoff Joao Martins
2021-11-24 19:10 ` [PATCH v6 06/10] device-dax: use struct_size() Joao Martins
2021-11-24 19:10 ` [PATCH v6 07/10] device-dax: ensure dev_dax->pgmap is valid for dynamic devices Joao Martins
2021-11-24 19:10 ` [PATCH v6 08/10] device-dax: factor out page mapping initialization Joao Martins
2021-11-24 19:10 ` [PATCH v6 09/10] device-dax: set mapping prior to vmf_insert_pfn{,_pmd,pud}() Joao Martins
2021-11-25 11:42 ` Joao Martins [this message]
2021-11-26 18:39 ` Joao Martins
2021-11-29 7:32 ` Christoph Hellwig
2021-11-29 15:49 ` Joao Martins
2021-11-29 16:48 ` Christoph Hellwig
2021-11-29 17:20 ` Joao Martins
2021-11-24 19:10 ` [PATCH v6 10/10] device-dax: compound devmap support Joao Martins
2021-11-24 22:30 ` [PATCH v6 00/10] mm, device-dax: Introduce compound pages in devmap Dan Williams
2021-11-24 22:41 ` Andrew Morton
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