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| /openbmc/linux/drivers/mmc/host/ |
| H A D | omap_hsmmc.c | 94424004 Thu Jun 22 05:57:53 CDT 2017 Will Newton <will.newton@gmail.com> mmc: omap_hsmmc: Reduce max_segs for reliability
Reduce max_segs to 64, a value that allows allocation of an entire
EDMA descriptor list within a single page - EDMA descriptors
are 40 bytes and the header is much larger. This avoids doing a
higher order GFP_ATOMIC allocation in edma_prep_slave_sg
when setting up a transfer which can potentially fail due to
fragmentation under heavy I/O load.
The current value of 1024 is unusually high in comparison to
other mmc host drivers which mostly use values of between 1
and 256. The EDMA driver at present splits lists above 20
segments in any case so reducing the size of lists we pass to
it shouldn't add much overhead.
Signed-off-by: Will Newton <willn@resin.io>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
94424004 Thu Jun 22 05:57:53 CDT 2017 Will Newton <will.newton@gmail.com> mmc: omap_hsmmc: Reduce max_segs for reliability
Reduce max_segs to 64, a value that allows allocation of an entire
EDMA descriptor list within a single page - EDMA descriptors
are 40 bytes and the header is much larger. This avoids doing a
higher order GFP_ATOMIC allocation in edma_prep_slave_sg
when setting up a transfer which can potentially fail due to
fragmentation under heavy I/O load.
The current value of 1024 is unusually high in comparison to
other mmc host drivers which mostly use values of between 1
and 256. The EDMA driver at present splits lists above 20
segments in any case so reducing the size of lists we pass to
it shouldn't add much overhead.
Signed-off-by: Will Newton <willn@resin.io>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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