Hi Hiroshi, On Wed, Apr 28, 2010 at 10:50 AM, Hiroshi DOYU <Hiroshi.DOYU@xxxxxxxxx> wrote: > Hi Ohad, > > From: ext Ohad Ben-Cohen <ohad@xxxxxxxxxx> > Subject: [PATCH 1/4] omap: mailbox cleanup: convert rwlocks to spinlock > Date: Tue, 27 Apr 2010 19:56:19 +0200 > >> rwlocks are slower and have potential starvation issues so spinlocks are >> generally preferred > > Would it be possible to explain the above a bit more? Sure, sorry for the laconic description. Jonathan Corbet wrote a nice summary about this: http://lwn.net/Articles/364583/ We could switch to rcu, but it's really an overkill because we don't really have a high bandwidth of readers (omap_mbox_get is not being called so much). The only disadvantage of a plain spinlock is that readers now will have to wait in the line, but since omap_mbox_get isn't called so frequently, I guess that by moving to spinlocks the average performance will actually increase (since spinlocks are faster and most likely there will not be multiple concurrent calls to omap_mbox_get). Anyway I only consider this as a cleanup and not really a performance issue, as mboxes_lock is not really on a hot path. Thanks, Ohad. > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
