Ross Zwisler <ross.zwis...@linux.intel.com> writes: > This series implements the very slow but correct handling for > blkdev_issue_flush() with DAX mappings, as discussed here: > > https://lkml.org/lkml/2015/10/26/116 > > I don't think that we can actually do the > > on_each_cpu(sync_cache, ...); > > ...where sync_cache is something like: > > cache_disable(); > wbinvd(); > pcommit(); > cache_enable(); > > solution as proposed by Dan because WBINVD + PCOMMIT doesn't guarantee that > your writes actually make it durably onto the DIMMs. I believe you really do > need to loop through the cache lines, flush them with CLWB, then fence and > PCOMMIT.
*blink* *blink* So much for not violating the principal of least surprise. I suppose you've asked the hardware folks, and they've sent you down this path? > I do worry that the cost of blindly flushing the entire PMEM namespace on each > fsync or msync will be prohibitively expensive, and that we'll by very > incentivized to move to the radix tree based dirty page tracking as soon as > possible. :) Sure, but wbinvd would be quite costly as well. Either way I think a better solution will be required in the near term. Cheers, Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
