On Thu, Feb 02, 2023 at 03:38:58PM +0100, Christoph Lameter wrote: > On Wed, 1 Feb 2023, Marcelo Tosatti wrote: > > > In preparation to switch vmstat shepherd to flush > > per-CPU counters remotely, use a cmpxchg loop > > instead of a pair of read/write instructions. > > You are mixing full atomic cmpxchg and per cpu atomic cmpxchg? That does > not work. OK, missing locked on the local functions. Can fix that. > I thought you would only run this while the kernel is not active on the > remote cpu? Then you dont need any cmpxchg and you can leave the function > as is. The remote cpu can enter kernel mode while this function executes. There is no mode which indicates userspace cannot enter the kernel.
