Re: [PATCH 1/2] fs: Do not dispatch FITRIM through separate super_operation

Jeff Moyer
2010-11-18T17:27:20Z

James Bottomley <James.Bottomley@suse.de> writes:

> Not stepping into the debate: I'm happy to see punch go to the mapping
> data and FITRIM pick it up later.
>
> However, I think it's time to question whether we actually still want to
> allow online discard at all. Most of the benchmarks show it to be a net

Define online discard, please.

> lose to almost everything (either SSD or Thinly Provisioned arrays), so
> it's become an "enable this to degrade performance" option with no
> upside.

Some SSDs very much require TRIMming to perform well as they age. If
you're suggesting that we move from doing discards in journal commits to
a batched discard, like the one Lukas implemented, then I think that's
fine. If we need to reintroduce the finer-grained discards due to some
hardware changes in the future, we can always do that.

Cheers,
Jeff