On Sat, 22 Jul 2023 at 00:55, Pedro Falcato <pedro.falc...@gmail.com> wrote: > > On Thu, Jul 20, 2023 at 2:46 PM Ard Biesheuvel <a...@kernel.org> wrote: > > > > Instead of relying on raising the TPL to protect the critical sections > > that manipulate the global bitmask that keeps track of bounce buffer > > allocations, use compare-and-exchange to manage the global variable, and > > tweak the logic to line up with that. > > > > Given that IoMmuDxe implements a singleton protocol that is shared > > between multiple drivers, and considering the elaborate and confusing > > requirements in the UEFP spec regarding TPL levels at which protocol > > methods may be invoked, not relying on TPL levels at all is a more > > Really good change (I had thought of this when reading through the > other IoMmuDxe thread), but I'm wondering if this warrants the > addition of bit ops (AND, OR at least) to SynchronizationLib? >
Thanks. Atomic AND/OR would only help on the free path in this case. > Sidenote: the compiler can detect if atomic intrinsics use the "fetch" > value in (fetch_or, or_fetch, etc) and thus use smaller, more > efficient instruction sequences (https://godbolt.org/z/zWTTWacEd). if > only we could use those... > In principle, I'd agree but these are rarely used so I'm not sure it's worth the effort refactoring this. -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#107171): https://edk2.groups.io/g/devel/message/107171 Mute This Topic: https://groups.io/mt/100256049/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
