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? :(
+ /*
+ * 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?
Thanks!
