On 25.05.2022 12:52, Andrew Cooper wrote: > On 25/05/2022 09:13, Roger Pau Monne wrote: >> Rename the flag to better note that it's not actually forcing any IPIs >> to be issued if none is required, but merely avoiding the usage of TLB >> flush assistance (which itself can avoid the sending of IPIs to remote >> processors). >> >> No functional change expected. >> >> Requested-by: Jan Beulich <[email protected]> >> Signed-off-by: Roger Pau Monné <[email protected]> >> --- >> Changes since v2: >> - New in this version. > > :( This needs reverting. > > It is specific to IPIs, because of our current choice of algorithm for > freeing pagetables. > > "no assist" excludes ipi-helper hypercalls which invoke > INVALIDATE_TLB_VECTOR. Such hypercalls do exist and specifically would > be improvement that we ought to use. > > Furthermore, we do want to work around the limitation that created > FLUSH_FORCE_IPI, because we absolutely do want to be able to use > hypercalls/remote TLB flushing capabilities when available. > > I accept that FORCE_IPI perhaps isn't a perfect name, but it's a whole > lot less bad than NO_ASSIST.
But FORCE_IPI has caused actual confusion while reviewing patch 2. If NO_ASSIST doesn't suit you and FORCE_IPI is also wrong, can you suggest a better name fitting both aspects? Jan
