On Tue, Sep 27, 2016 at 09:30:55AM +0200, Peter Zijlstra wrote: > > Also, if those bitlock ops had a different bit that showed contention, > > we could actually skip *all* of this, and just see that "oh, nobody is > > waiting on this page anyway, so there's no point in looking up those > > wait queues". We don't have that many "__wait_on_bit()" users, maybe > > we could say that the bitlocks do have to haev *two* bits: one for the > > lock bit itself, and one for "there is contention". > > That would be fairly simple to implement, the difficulty would be > actually getting a page-flag to use for this. We're running pretty low > in available bits :/ Simple is relative unless I drastically overcomplicated things and it wouldn't be the first time. 64-bit only side-steps the page flag issue as long as we can live with that. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>