Messages in this thread | | | Date | Fri, 6 Nov 2015 18:35:11 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCH 0/2] "big hammer" for DAX msync/fsync correctness |
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On Fri, 6 Nov 2015, Dan Williams wrote: > On Fri, Nov 6, 2015 at 12:06 AM, Thomas Gleixner <tglx@linutronix.de> wrote: > > Just for the record. Such a flush mechanism with > > > > on_each_cpu() > > wbinvd() > > ... > > > > will make that stuff completely unusable on Real-Time systems. We've > > been there with the big hammer approach of the intel graphics > > driver. > > Noted. This means RT systems either need to disable DAX or avoid > fsync. Yes, this is a wart, but not an unexpected one in a first > generation persistent memory platform.
And it's not just only RT. The folks who are aiming for 100% undisturbed user space (NOHZ_FULL) will be massively unhappy about that as well.
Is it really required to do that on all cpus?
Thanks,
tglx
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