Messages in this thread | | | Date | Sat, 30 May 1998 16:49:13 +0200 | From | Pavel Machek <> | Subject | Re: test_and_set_bit() not atomic forever? [cli/sti in char/vt.c [patch]] |
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Hi!
> >Don't think so. Well, it is safe on i386, but on other architectures, > >test_and_set_bit is not guaranteed to be atomic. [And I'm afraid that > > Arggh I thought that test_and_set_bit() was atomic on all ports (since I > looked only its i386 implementation)!
Mistake.
> At first I can see test_and_set_bit() very more helpful if > implemented atomic.
I was told that atomic test_and_set_bit would be too expensive on sparc.
> As second since it' s declared _not_ atomic in Linux, why i386 implement > it atomic?
Because in i386 port it _IS_ atomic, so in arch/i386 you can assume that test_and_set_bit is atomic. Strange, is not it? Should be documented somewhere.
Pavel
-- I'm really pavel@atrey.karlin.mff.cuni.cz. Pavel Look at http://atrey.karlin.mff.cuni.cz/~pavel/ ;-).
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