Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it

Christoph Lameter <[email protected]> wrote:

> cmpxchg is the simplest solution to realize many other atomic operations and
> its widely available on a wide variety of platforms.

But by no means all.  Where it doesn't exist it can only be properly emulated
by something such as LL/SC if they are there.  If not, then you can't do a
safe cmpxchg on SMP.

> It is the most universal atomic instruction that I know of.

I think TAS-type things and XCHG-type things are more common.

In fact I think more things have LL/SC than have CMPXCHG.

David
-
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/

---

• Follow-Ups:
  • Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
    • From: Linus Torvalds <[email protected]>
  • Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
    • From: Christoph Lameter <[email protected]>

• References:
  • Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
    • From: Christoph Lameter <[email protected]>
  • [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
    • From: David Howells <[email protected]>
  • Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
    • From: Christoph Lameter <[email protected]>
  • Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
    • From: Russell King <[email protected]>
  • Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
    • From: Christoph Lameter <[email protected]>
  • Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
    • From: Russell King <[email protected]>
  • Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
    • From: Nick Piggin <[email protected]>
  • Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
    • From: Russell King <[email protected]>
  • Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
    • From: Nick Piggin <[email protected]>
  • Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
    • From: Russell King <[email protected]>

• Prev by Date: Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
• Next by Date: Re: additional oom-killer tuneable worth submitting?
• Previous by thread: Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
• Next by thread: Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
• Index(es):
  • Date
  • Thread

[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]