On Mon, Dec 09, 2024 at 01:04:43PM +0100, Valentin Schneider wrote: > > But I wonder what exactly was the original scenario encountered by > > Valentin. I mean, if TLB entry invalidations were necessary to sync > > changes to kernel text after flipping a static branch, then it might be > > less overhead to make a list of affected pages and call INVLPG on them. No; TLB is not involved with text patching (on x86). > > Valentin, do you happen to know? > > So from my experimentation (hackbench + kernel compilation on housekeeping > CPUs, dummy while(1) userspace loop on isolated CPUs), the TLB flushes only > occurred from vunmap() - mainly from all the hackbench threads coming and > going. Right, we have virtually mapped stacks.
