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| author | Myron Stowe <myron.stowe@hp.com> | 2010-10-21 22:24:14 +0200 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2010-10-25 05:31:43 +0200 |
| commit | 4a3cba5e72a5232842ff7c1ca691ec3450af64b9 (patch) | |
| tree | bcf2659d20f6b8383f3c42d066595832097ca46e /drivers/acpi/video.c | |
| parent | ACPI: Convert simple locking to RCU based locking (diff) | |
| download | linux-4a3cba5e72a5232842ff7c1ca691ec3450af64b9.tar.xz linux-4a3cba5e72a5232842ff7c1ca691ec3450af64b9.zip | |
ACPI: Page based coalescing of I/O remappings optimization
This patch optimizes ACPI MMIO remappings by keeping track of the
remappings on a PAGE_SIZE granularity.
When an ioremap() occurs, the underlying infrastructure works on a 'page'
based granularity. As such, an ioremap() request for 1 byte for example,
will end up mapping in an entire (PAGE_SIZE) page. Huang Ying took
advantage of this in commit 15651291a2f8c11e7e6a42d8bfde7a213ff13262 by
checking if subsequent ioremap() requests reside within any of the list's
existing remappings still in place, and if so, incrementing a reference
count on the existing mapping as opposed to performing another ioremap().
Signed-off-by: Myron Stowe <myron.stowe@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi/video.c')
0 files changed, 0 insertions, 0 deletions