On 22/05/2018 17:42, Raslan, KarimAllah wrote: > On Mon, 2018-04-16 at 18:28 +0200, Paolo Bonzini wrote: >> On 15/04/2018 00:26, KarimAllah Ahmed wrote: >>> >>> Switch 'requests' to be explicitly 64-bit and update BUILD_BUG_ON check to >>> use the size of "requests" instead of the hard-coded '32'. >>> >>> That gives us a bit more room again for arch-specific requests as we >>> already ran out of space for x86 due to the hard-coded check. >>> >>> Cc: Paolo Bonzini <[email protected]> >>> Cc: Radim Krčmář <[email protected]> >>> Cc: [email protected] >>> Cc: [email protected] >>> Signed-off-by: KarimAllah Ahmed <[email protected]> >> >> I'm afraid architectures like ARM 32 need this to be conditional (using >> Kconfig). > > Why would using a 64-bit 'requests' be a problem for ARM32? Are you > concerned about performance here or is there some symantic problem?
They don't support atomics on double-word data. Paolo
