* Xiao Guangrong (guangrong.xiao@xxxxxxxxx) wrote: > > > On 11/23/18 7:02 PM, Dr. David Alan Gilbert wrote: > > > > +#include "qemu/osdep.h" > > > +#include "qemu/bitmap.h" > > > +#include "qemu/threaded-workqueue.h" > > > + > > > +#define SMP_CACHE_BYTES 64 > > > > That's architecture dependent isn't it? > > > > Yes, it's arch dependent indeed. > > I just used 64 for simplification and i think it is <= 64 on most CPU arch-es > so that can work. > > Should i introduce statically defined CACHE LINE SIZE for all arch-es? :( I think it depends why you need it; but we shouldn't have a constant that is wrong, and we shouldn't define something architecture dependent in here. > > > + /* > > > + * the bit in these two bitmaps indicates the index of the ＠requests > > > + * respectively. If it's the same, the corresponding request is free > > > + * and owned by the user, i.e, where the user fills a request. Otherwise, > > > + * it is valid and owned by the thread, i.e, where the thread fetches > > > + * the request and write the result. > > > + */ > > > + > > > + /* after the user fills the request, the bit is flipped. */ > > > + uint64_t request_fill_bitmap QEMU_ALIGNED(SMP_CACHE_BYTES); > > > + /* after handles the request, the thread flips the bit. */ > > > + uint64_t request_done_bitmap QEMU_ALIGNED(SMP_CACHE_BYTES); > > > > Patchew complained about some type mismatches; I think those are because > > you're using the bitmap_* functions on these; those functions always > > operate on 'long' not on uint64_t - and on some platforms they're > > unfortunately not the same. > > I guess you were taking about this error: > ERROR: externs should be avoided in .c files > #233: FILE: util/threaded-workqueue.c:65: > + uint64_t request_fill_bitmap QEMU_ALIGNED(SMP_CACHE_BYTES); > > The complained thing is "QEMU_ALIGNED(SMP_CACHE_BYTES)" as it gone > when the aligned thing is removed... > > The issue you pointed out can be avoid by using type-casting, like: > bitmap_xor(..., (void *)&thread->request_fill_bitmap) > cannot we? I thought the error was just due to long vs uint64_t ratehr than the qemu_aligned. I don't think it's just a casting problem, since I don't think the long's are always 64bit. Dave > Thanks! -- Dr. David Alan Gilbert / dgilbert@xxxxxxxxxx / Manchester, UK
