Keith Busch df06b37ffe mm/gup: cache dev_pagemap while pinning pages ... Getting pages from ZONE_DEVICE memory needs to check the backing device's live-ness, which is tracked in the device's dev_pagemap metadata. This metadata is stored in a radix tree and looking it up adds measurable software overhead. This patch avoids repeating this relatively costly operation when dev_pagemap is used by caching the last dev_pagemap while getting user pages. The gup_benchmark kernel self test reports this reduces time to get user pages to as low as 1/3 of the previous time. Link: http://lkml.kernel.org/r/20181012173040.15669-1-keith.busch@intel.com Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2018-10-26 16:38:15 -07:00
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acpi
asm-generic
clocksource
crypto
drm
dt-bindings
keys
kvm
linux	mm/gup: cache dev_pagemap while pinning pages	2018-10-26 16:38:15 -07:00
math-emu
media
memory
misc
net
pcmcia
ras
rdma
scsi
soc
sound
target
trace
uapi
video
xen