Luca Porzio d3df0465db mmc: remove bondage between REQ_META and reliable write ... Anytime a write operation is performed with Reliable Write flag enabled, the eMMC device is enforced to bypass the cache and do a write to the underling NVM device by Jedec specification; this causes a performance penalty since write operations can't be optimized by the device cache. In our tests, we replayed a typical mobile daily trace pattern and found ~9% overall time reduction in trace replay by using this patch. Also the write ops within 4KB~64KB chunk size range get a 40~60% performance improvement by using the patch (as this range of write chunks are the ones affected by REQ_META). This patch has been discussed in the Mobile & Embedded Linux Storage Forum and it's the results of feedbacks from many people. We also checked with fsdevl and f2fs mailing list developers that this change in the usage of REQ_META is not affecting FS behavior and we got positive feedbacks. Reporting here the feedbacks: http://comments.gmane.org/gmane.linux.file-systems/97219 http://thread.gmane.org/gmane.linux.file-systems.f2fs/3178/focus=3183 Signed-off-by: Bruce Ford <bford@micron.com> Signed-off-by: Luca Porzio <lporzio@micron.com> Fixes: ce39f9d17c ("mmc: support packed write command for eMMC4.5 devices") Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>		2015-11-09 14:04:52 +01:00
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card	mmc: remove bondage between REQ_META and reliable write	2015-11-09 14:04:52 +01:00
core	mmc: mmc: Improve reliability of mmc_select_hs400()	2015-11-09 13:16:32 +01:00
host	mmc: MMC_GOLDFISH should depend on HAS_DMA	2015-11-09 13:16:45 +01:00
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