diff options
| author | Will Newton <will.newton@gmail.com> | 2017-06-22 11:57:53 +0100 |
|---|---|---|
| committer | Ulf Hansson <ulf.hansson@linaro.org> | 2017-08-30 14:01:22 +0200 |
| commit | 9442400486a1ec28915e9ab31517a5665ed35705 (patch) | |
| tree | db07558c3b70d373ead6db1f0f57d5f211c8ddc8 /drivers/mmc/host/omap_hsmmc.c | |
| parent | 163671845092af687ef5104ecb2e5b461f4c46d4 (diff) | |
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>
Diffstat (limited to 'drivers/mmc/host/omap_hsmmc.c')
| -rw-r--r-- | drivers/mmc/host/omap_hsmmc.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c index 26c97b2ee7e6..3b5e6d11069b 100644 --- a/drivers/mmc/host/omap_hsmmc.c +++ b/drivers/mmc/host/omap_hsmmc.c @@ -2076,9 +2076,9 @@ static int omap_hsmmc_probe(struct platform_device *pdev) host->dbclk = NULL; } - /* Since we do only SG emulation, we can have as many segs - * as we want. */ - mmc->max_segs = 1024; + /* Set this to a value that allows allocating an entire descriptor + * list within a page (zero order allocation). */ + mmc->max_segs = 64; mmc->max_blk_size = 512; /* Block Length at max can be 1024 */ mmc->max_blk_count = 0xFFFF; /* No. of Blocks is 16 bits */ |