On Mon, 2018-07-16 at 03:04 +0200, Ingo Molnar wrote: > * Rik van Riel <[email protected]> wrote: > > > On Mon, 2018-07-16 at 01:04 +0200, Ingo Molnar wrote: > > > * Rik van Riel <[email protected]> wrote: > > > > > > > + /* > > > > + * Stop remote flushes for the previous mm. > > > > + * Skip the idle task; we never send init_mm > > > > TLB > > > > flushing IPIs, > > > > + * but the bitmap manipulation can cause cache > > > > line contention. > > > > + */ > > > > + if (real_prev != &init_mm) { > > > > + VM_WARN_ON_ONCE(!cpumask_test_cpu(cpu, > > > > + mm_cpumask(rea > > > > l_pr > > > > ev))); > > > > + cpumask_clear_cpu(cpu, > > > > mm_cpumask(real_prev)); > > > > > > BTW., could this optimization be (safely) extended to all (or > > > most) > > > !task->mm > > > kernel threads? > > > > > > In particular softirq and threaded irq handlers could benefit > > > greatly > > > I suspect in > > > certain networking intense workloads that happen to active them. > > > > Yes, it could. > > > > Are there kernel threads that use something other than > > init_mm today? > > Yeah, I think that's the typical case - so at minimum the comment > should be fixed: > > > > > + * Skip the idle task; we never send init_mm TLB > flushing IPIs, > > and it should say 'skip kernel threads', right?
I will send a v6 that improves this comment, and has the S-o-b thing you suggested for patch 1/7. I think that addresses all the comments people had on this patch series. -- All Rights Reversed.
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