Re: [PATCH v12 0/10] Support Write-Through mapping on x86

[Luis R. Rodriguez]

On Mon, Jun 01, 2015 at 01:36:23PM -0600, Toshi Kani wrote:
> This patchset adds support of Write-Through (WT) mapping on x86.
> The study below shows that using WT mapping may be useful for
> non-volatile memory.
> 
> http://www.hpl.hp.com/techreports/2012/HPL-2012-236.pdf
> 
> The patchset consists of the following changes.
>  - Patch 1/10 to 6/10 add ioremap_wt()
>  - Patch 7/10 adds pgprot_writethrough()
>  - Patch 8/10 to 9/10 add set_memory_wt()
>  - Patch 10/10 changes the pmem driver to call ioremap_wt()
> 
> All new/modified interfaces have been tested.
> 
> The patchset is based on:
> git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp.git#tip-mm-2

While at it can you also look at:

mcgrof@ergon ~/linux-next (git::master)$ git grep -4 "writethrough" drivers/infiniband/

drivers/infiniband/hw/ipath/ipath_driver.c-
drivers/infiniband/hw/ipath/ipath_driver.c-     dd->ipath_pcirev = pdev->revision;
drivers/infiniband/hw/ipath/ipath_driver.c-
drivers/infiniband/hw/ipath/ipath_driver.c-#if defined(__powerpc__)
drivers/infiniband/hw/ipath/ipath_driver.c:     /* There isn't a generic way to specify writethrough mappings */
drivers/infiniband/hw/ipath/ipath_driver.c-     dd->ipath_kregbase = __ioremap(addr, len,
drivers/infiniband/hw/ipath/ipath_driver.c-             (_PAGE_NO_CACHE|_PAGE_WRITETHRU));
drivers/infiniband/hw/ipath/ipath_driver.c-#else
drivers/infiniband/hw/ipath/ipath_driver.c-     dd->ipath_kregbase = ioremap_nocache(addr, len);
--
drivers/infiniband/hw/ipath/ipath_file_ops.c-
drivers/infiniband/hw/ipath/ipath_file_ops.c-   phys = dd->ipath_physaddr + piobufs;
drivers/infiniband/hw/ipath/ipath_file_ops.c-
drivers/infiniband/hw/ipath/ipath_file_ops.c-#if defined(__powerpc__)
drivers/infiniband/hw/ipath/ipath_file_ops.c:   /* There isn't a generic way to specify writethrough mappings */
drivers/infiniband/hw/ipath/ipath_file_ops.c-   pgprot_val(vma->vm_page_prot) |= _PAGE_NO_CACHE;
drivers/infiniband/hw/ipath/ipath_file_ops.c-   pgprot_val(vma->vm_page_prot) |= _PAGE_WRITETHRU;
drivers/infiniband/hw/ipath/ipath_file_ops.c-   pgprot_val(vma->vm_page_prot) &= ~_PAGE_GUARDED;
drivers/infiniband/hw/ipath/ipath_file_ops.c-#endif
--
drivers/infiniband/hw/qib/qib_file_ops.c-
drivers/infiniband/hw/qib/qib_file_ops.c-       phys = dd->physaddr + piobufs;
drivers/infiniband/hw/qib/qib_file_ops.c-
drivers/infiniband/hw/qib/qib_file_ops.c-#if defined(__powerpc__)
drivers/infiniband/hw/qib/qib_file_ops.c:       /* There isn't a generic way to specify writethrough mappings */
drivers/infiniband/hw/qib/qib_file_ops.c-       pgprot_val(vma->vm_page_prot) |= _PAGE_NO_CACHE;
drivers/infiniband/hw/qib/qib_file_ops.c-       pgprot_val(vma->vm_page_prot) |= _PAGE_WRITETHRU;
drivers/infiniband/hw/qib/qib_file_ops.c-       pgprot_val(vma->vm_page_prot) &= ~_PAGE_GUARDED;
drivers/infiniband/hw/qib/qib_file_ops.c-#endif
--
drivers/infiniband/hw/qib/qib_pcie.c-   addr = pci_resource_start(pdev, 0);
drivers/infiniband/hw/qib/qib_pcie.c-   len = pci_resource_len(pdev, 0);
drivers/infiniband/hw/qib/qib_pcie.c-
drivers/infiniband/hw/qib/qib_pcie.c-#if defined(__powerpc__)
drivers/infiniband/hw/qib/qib_pcie.c:   /* There isn't a generic way to specify writethrough mappings */
drivers/infiniband/hw/qib/qib_pcie.c-   dd->kregbase = __ioremap(addr, len, _PAGE_NO_CACHE | _PAGE_WRITETHRU);
drivers/infiniband/hw/qib/qib_pcie.c-#else
drivers/infiniband/hw/qib/qib_pcie.c-   dd->kregbase = ioremap_nocache(addr, len);
drivers/infiniband/hw/qib/qib_pcie.c-#endif

  Luis
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