> On Jul 27, 2017, at 3:53 PM, Andrew Banman <abanman@xxxxxxx> wrote: > >> On Thu, Jun 22, 2017 at 10:47:29AM -0700, Andy Lutomirski wrote: >>> On Thu, Jun 22, 2017 at 7:50 AM, Borislav Petkov <bp@xxxxxxxxx> wrote: >>>> On Tue, Jun 20, 2017 at 10:22:12PM -0700, Andy Lutomirski wrote: >>>> Rewrite it entirely. When we enter lazy mode, we simply remove the >>>> cpu from mm_cpumask. This means that we need a way to figure out >>> >>> s/cpu/CPU/ >> >> Done. >> >>> >>>> whether we've missed a flush when we switch back out of lazy mode. >>>> I use the tlb_gen machinery to track whether a context is up to >>>> date. >>>> >>>> Note to reviewers: this patch, my itself, looks a bit odd. I'm >>>> using an array of length 1 containing (ctx_id, tlb_gen) rather than >>>> just storing tlb_gen, and making it at array isn't necessary yet. >>>> I'm doing this because the next few patches add PCID support, and, >>>> with PCID, we need ctx_id, and the array will end up with a length >>>> greater than 1. Making it an array now means that there will be >>>> less churn and therefore less stress on your eyeballs. >>>> >>>> NB: This is dubious but, AFAICT, still correct on Xen and UV. >>>> xen_exit_mmap() uses mm_cpumask() for nefarious purposes and this >>>> patch changes the way that mm_cpumask() works. This should be okay, >>>> since Xen *also* iterates all online CPUs to find all the CPUs it >>>> needs to twiddle. >>> >>> This whole text should be under the "---" line below if we don't want it >>> in the commit message. >> >> I figured that some future reader of this patch might actually want to >> see this text, though. >> >>> >>>> >>>> The UV tlbflush code is rather dated and should be changed. >> >> And I'd definitely like the UV maintainers to notice this part, now or >> in the future :) I don't want to personally touch the UV code with a >> ten-foot pole, but it really should be updated by someone who has a >> chance of getting it right and being able to test it. > > Noticed! We're aware of these changes and we're planning on updating this > code in the future. Presently the BAU tlb shootdown feature is working well > on our recent hardware. :) I would suggest reworking it to hook the SMP function call infrastructure instead of the TLB shootdown code. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
