Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 6 Aug 2020 11:32:20 -0700 | Subject | Re: [RFC PATCH] mm: silence soft lockups from unlock_page |
| |
On Thu, Aug 6, 2020 at 11:00 AM Matthew Wilcox <willy@infradead.org> wrote: > > It wasn't clear to me whether Hugh thought it was an improvement or > not that trylock was now less likely to jump the queue. There're > the usual "fair is the opposite of throughput" kind of arguments.
Yeah, it could go either way. But on the whole, if the lock bit is getting any contention, I think we'd rather have it be fair for latency reasons.
That said, I'm not convinced about my patch, and I actually threw it away without even testing it (sometimes I keep patches around in my private tree for testing, and they can live there for months or even years when I wonder if they are worth it, but this time I didn't bother to go to the trouble).
If somebody is interested in pursuing this, I think that patch might be a good starting point (and it _might_ even work), but it seemed to be too subtle to really worry about unless somebody finds an actual acute reason for it.
I think the existing patch narrowing the window is good, and it clearly didn't hurt throughput (although that was almost certainly for other reasons).
Linus
| |