On Tue, Oct 31, 2017 at 3:32 PM, Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> wrote: > > If we change the page tables in such a way that we need an > invalidation of all contexts (aka. PCIDs / ASIDs) we can > actively invalidate them by: > 1. INVPCID for each PCID (works for single pages too). > 2. Load CR3 with each PCID without the NOFLUSH bit set > 3. Load CR3 with the NOFLUSH bit set for each and do > INVLPG for each address. > > But, none of these are really feasible since we have ~6 ASIDs (12 with > KAISER) at the time that we need to do an invalidation. So, we just > invalidate the *current* context and then mark the cpu_tlbstate > _quickly_. > > Then, at the next context-switch, we notice that we had > 'all_other_ctxs_invalid' marked, and go invalidate all of the > cpu_tlbstate.ctxs[] entries. > > This ensures that any futuee context switches will do a full flush > of the TLB so they pick up the changes. I'm convuced. What was wrong with the old code? I guess I just don't see what the problem is that is solved by this patch. -- 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>
