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@xxxxxxxx> --- drivers/mmc/host/omap_hsmmc.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) Changes in v2: - More verbose commit message - Rebased onto current master diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c index 8c39dcc..bbcca93 100644 --- a/drivers/mmc/host/omap_hsmmc.c +++ b/drivers/mmc/host/omap_hsmmc.c @@ -2097,9 +2097,9 @@ 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 */ -- 2.9.4 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
