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authorDan Williams <dan.j.williams@intel.com>2016-09-07 08:51:21 -0700
committerDan Williams <dan.j.williams@intel.com>2016-09-09 17:34:46 -0700
commit9049771f7d5490a302589976984810064c83ab40 (patch)
tree139176732c8a7a1ccf66ed7399cce292730732c5 /arch/x86/mm/pat.c
parentca120cf688874f4423e579e7cc5ddf7244aeca45 (diff)
mm: fix cache mode of dax pmd mappings
track_pfn_insert() in vmf_insert_pfn_pmd() is marking dax mappings as uncacheable rendering them impractical for application usage. DAX-pte mappings are cached and the goal of establishing DAX-pmd mappings is to attain more performance, not dramatically less (3 orders of magnitude). track_pfn_insert() relies on a previous call to reserve_memtype() to establish the expected page_cache_mode for the range. While memremap() arranges for reserve_memtype() to be called, devm_memremap_pages() does not. So, teach track_pfn_insert() and untrack_pfn() how to handle tracking without a vma, and arrange for devm_memremap_pages() to establish the write-back-cache reservation in the memtype tree. Cc: <stable@vger.kernel.org> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Nilesh Choudhury <nilesh.choudhury@oracle.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Toshi Kani <toshi.kani@hpe.com> Reported-by: Kai Zhang <kai.ka.zhang@oracle.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'arch/x86/mm/pat.c')
-rw-r--r--arch/x86/mm/pat.c17
1 files changed, 10 insertions, 7 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index ecb1b69c1651..170cc4ff057b 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -927,9 +927,10 @@ int track_pfn_copy(struct vm_area_struct *vma)
}
/*
- * prot is passed in as a parameter for the new mapping. If the vma has a
- * linear pfn mapping for the entire range reserve the entire vma range with
- * single reserve_pfn_range call.
+ * prot is passed in as a parameter for the new mapping. If the vma has
+ * a linear pfn mapping for the entire range, or no vma is provided,
+ * reserve the entire pfn + size range with single reserve_pfn_range
+ * call.
*/
int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
unsigned long pfn, unsigned long addr, unsigned long size)
@@ -938,11 +939,12 @@ int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
enum page_cache_mode pcm;
/* reserve the whole chunk starting from paddr */
- if (addr == vma->vm_start && size == (vma->vm_end - vma->vm_start)) {
+ if (!vma || (addr == vma->vm_start
+ && size == (vma->vm_end - vma->vm_start))) {
int ret;
ret = reserve_pfn_range(paddr, size, prot, 0);
- if (!ret)
+ if (ret == 0 && vma)
vma->vm_flags |= VM_PAT;
return ret;
}
@@ -997,7 +999,7 @@ void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
resource_size_t paddr;
unsigned long prot;
- if (!(vma->vm_flags & VM_PAT))
+ if (vma && !(vma->vm_flags & VM_PAT))
return;
/* free the chunk starting from pfn or the whole chunk */
@@ -1011,7 +1013,8 @@ void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
size = vma->vm_end - vma->vm_start;
}
free_pfn_range(paddr, size);
- vma->vm_flags &= ~VM_PAT;
+ if (vma)
+ vma->vm_flags &= ~VM_PAT;
}
/*