Messages in this thread | | | Subject | Re: [RFC PATCH v2 2/3] x86/mm/tlb: Defer PTI flushes | From | Dave Hansen <> | Date | Tue, 27 Aug 2019 11:28:53 -0700 |
| |
On 8/23/19 3:52 PM, Nadav Amit wrote: > INVPCID is considerably slower than INVLPG of a single PTE. Using it to > flush the user page-tables when PTI is enabled therefore introduces > significant overhead.
I'm not sure this is worth all the churn, especially in the entry code. For large flushes (> tlb_single_page_flush_ceiling), we don't do INVPCIDs in the first place.
I'd really want to understand what the heck is going on that makes INVPCID so slow, first.
| |