Re: Synchronizing Bit operations V2

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Christoph Lameter wrote:
Changelog:

V2
	- Fix various oversights
	- Follow Hans Boehm's scheme for the barrier logic

The following patchset implements the ability to specify a
synchronization mode for bit operations.

I.e. instead of set_bit(x,y) we can do set_bit(x,y, mode).

The following modes are supported:


This has acquire and release, instead of the generic kernel
memory barriers rmb and wmb. As such, I don't think it would
get merged.

Note that the current semantics for bitops IA64 are broken. Both
smp_mb__after/before_clear_bit are now set to full memory barriers
to compensate which may affect performance.

I think you should fight the fights you can win and get a 90%
solution ;) at any rate you do need to fix the existing routines
unless you plan to audit all callers...

First, fix up ia64 in 2.6-head, this means fixing test_and_set_bit
and friends, smp_mb__*_clear_bit, and all the atomic operations that
both modify and return a value.

Then add test_and_set_bit_lock / clear_bit_unlock, and apply them
to a couple of critical places like page lock and buffer lock.

Is this being planned?

--
SUSE Labs, Novell Inc.
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