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authorKeith Busch <keith.busch@intel.com>2018-10-26 15:10:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-10-26 16:38:15 -0700
commitdf06b37ffe5a442503b7095b77b0a970df515459 (patch)
tree2fdb301eba4b4c2240595040496096b3a6489c79 /drivers/pcmcia/pxa2xx_colibri.c
parent9fd61bc95130d4971568b89c9548b5e0a4e18e0e (diff)
downloadop-kernel-dev-df06b37ffe5a442503b7095b77b0a970df515459.zip
op-kernel-dev-df06b37ffe5a442503b7095b77b0a970df515459.tar.gz
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>
Diffstat (limited to 'drivers/pcmcia/pxa2xx_colibri.c')
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