Linux-kernel mailing list archive 2000-53,: Re: test13-pre5

# Re: test13-pre5

Andrea Arcangeli (andrea@suse.de)
Sun, 31 Dec 2000 19:10:46 +0100

- Messages sorted by: [ date ][ thread ][ subject ][ author ]
- Next message: Andrea Arcangeli: "Re: test13-pre5"
- Previous message: Matti Aarnio: "Re: test13-pre5"

On Sun, Dec 31, 2000 at 09:27:23AM -0800, Linus Torvalds wrote:
> The alpha systems I remember this problem on were all [..]

Yes the granularity issue has nothing to do with SMP (with preemptive kernel
it can trigger even without interrupts involved into the code). Also
CONFIG_SPACE_EFFICIENT looks not necessary.

The x8 name is confusing IMHO (when I read `8' I expect 8bits only, the x
isn't explicit enough). But by using a better name we could save some byte on
alpha ev6 and x86. Something like granular_char/granular_short/granular_int
looks nicer. For the generic 64bit cpu they needs to be _unconditionally_
defined to `long'.

BTW, only old chips (ev[45]) doesn't provide byte granularity. Infact a linux
kernel compiled for ev6 can handle byte granularity also on alpha (it uses
-mcpu=ev6).

alpha reference manual 5.2.2:

[..] For each region, an implementation must support aligned quadword
access and may optionally support aligned longword access or byte
access. If byte access is supported in a region, aligned word access
and aligned longword access are also supported. [..]

21264hrm:

[..] The 21264-generated external references to memory space are
always of a fixed 64-byte size, though the internal access granularity
is byte, word, longword, or quad-word. [..]

Andrea
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/

- Next message: Andrea Arcangeli: "Re: test13-pre5"
- Previous message: Matti Aarnio: "Re: test13-pre5"