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authorJoao Martins <joao.m.martins@oracle.com>2022-01-15 01:04:47 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2022-01-15 17:30:26 +0300
commit14606001efb48a17be31a5bec626c13ca49d783a (patch)
tree0ca8883b1b1050c53ae3cd76472704085d6c4275 /drivers/dax
parent6ec228b6fef5ad3a1f19e76c29640a9161415240 (diff)
downloadlinux-14606001efb48a17be31a5bec626c13ca49d783a.tar.xz
device-dax: compound devmap support
Use the newly added compound devmap facility which maps the assigned dax ranges as compound pages at a page size of @align. dax devices are created with a fixed @align (huge page size) which is enforced through as well at mmap() of the device. Faults, consequently happen too at the specified @align specified at the creation, and those don't change throughout dax device lifetime. MCEs unmap a whole dax huge page, as well as splits occurring at the configured page size. Performance measured by gup_test improves considerably for unpin_user_pages() and altmap with NVDIMMs: $ gup_test -f /dev/dax1.0 -m 16384 -r 10 -S -a -n 512 -w (pin_user_pages_fast 2M pages) put:~71 ms -> put:~22 ms [altmap] (pin_user_pages_fast 2M pages) get:~524ms put:~525 ms -> get: ~127ms put:~71ms $ gup_test -f /dev/dax1.0 -m 129022 -r 10 -S -a -n 512 -w (pin_user_pages_fast 2M pages) put:~513 ms -> put:~188 ms [altmap with -m 127004] (pin_user_pages_fast 2M pages) get:~4.1 secs put:~4.12 secs -> get:~1sec put:~563ms .. as well as unpin_user_page_range_dirty_lock() being just as effective as THP/hugetlb[0] pages. [0] https://lore.kernel.org/linux-mm/20210212130843.13865-5-joao.m.martins@oracle.com/ Link: https://lkml.kernel.org/r/20211202204422.26777-12-joao.m.martins@oracle.com Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/dax')
-rw-r--r--drivers/dax/device.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 60d43cb195da..591f293d326f 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -78,14 +78,20 @@ static void dax_set_mapping(struct vm_fault *vmf, pfn_t pfn,
{
unsigned long i, nr_pages = fault_size / PAGE_SIZE;
struct file *filp = vmf->vma->vm_file;
+ struct dev_dax *dev_dax = filp->private_data;
pgoff_t pgoff;
+ /* mapping is only set on the head */
+ if (dev_dax->pgmap->vmemmap_shift)
+ nr_pages = 1;
+
pgoff = linear_page_index(vmf->vma,
ALIGN(vmf->address, fault_size));
for (i = 0; i < nr_pages; i++) {
struct page *page = pfn_to_page(pfn_t_to_pfn(pfn) + i);
+ page = compound_head(page);
if (page->mapping)
continue;
@@ -443,6 +449,9 @@ int dev_dax_probe(struct dev_dax *dev_dax)
}
pgmap->type = MEMORY_DEVICE_GENERIC;
+ if (dev_dax->align > PAGE_SIZE)
+ pgmap->vmemmap_shift =
+ order_base_2(dev_dax->align >> PAGE_SHIFT);
addr = devm_memremap_pages(dev, pgmap);
if (IS_ERR(addr))
return PTR_ERR(addr);