On Wed, Oct 28, 2015 at 3:51 PM, Ross Zwisler <ross.zwis...@linux.intel.com> wrote: > On Wed, Oct 28, 2015 at 06:24:29PM -0400, Jeff Moyer wrote: >> 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? > > Sadly, yes, this was the guidance from the hardware folks.
So it turns out we weren't asking the right question. wbinvd may indeed be viable... we're still working through the caveats. -- 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/
