> The request itself has been
> touched by scsi_end_request() already, so unless the layout is really
> bad we shouldn't need to fetch a lot of cache lines there. That leaves
> __test_and_clear_bit(), I guess that must be it.
__test_and_clear_bit() is cheap; it's a single non-locked instruction.
Arguably it should be converted into a C variant so that the compiler
can pick the best code sequence (I'm not so sure the asm we picked for
this is optimal for all processors, I bet it'll be microcoded) but I'd
be surprised if it'd be more than a handful of cycles no matter what.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
