Messages in this thread | | | Subject | Re: [PATCH 1/2] locking: Implement an algorithm choice for Wound-Wait mutexes | From | Thomas Hellstrom <> | Date | Wed, 13 Jun 2018 10:34:02 +0200 |
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On 06/13/2018 09:54 AM, Greg Kroah-Hartman wrote: > On Wed, Jun 13, 2018 at 09:47:44AM +0200, Thomas Hellstrom wrote: >> ----- >> >> +The algorithm (Wait-Die vs Wound-Wait) is chosen using the _is_wait_die >> +argument to DEFINE_WW_CLASS(). As a rough rule of thumb, use Wound-Wait iff you >> +typically expect the number of simultaneous competing transactions to be small, >> +and the rollback cost can be substantial. >> + >> Three different ways to acquire locks within the same w/w class. Common >> definitions for methods #1 and #2: >> >> -static DEFINE_WW_CLASS(ww_class); >> +static DEFINE_WW_CLASS(ww_class, false); > Minor nit on the api here. Having a "flag" is a royal pain. You have > to go and look up exactly what that "true/false" means every time you > run across it in code to figure out what it means. Don't do that if at > all possible. > > Make a new api: > DEFINE_WW_CLASS_DIE(ww_class); > instead that then wraps that boolean internally to switch between the > different types. That way the api is "self-documenting" and we all know > what is going on without having to dig through a header file. > > thanks, > > greg k-h
Good point. I'll update in a v2.
Thanks,
Thomas
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