Messages in this thread | | | Date | Thu, 05 Aug 2010 07:22:30 +1000 | From | Nigel Cunningham <> | Subject | Re: 2.6.35 Regression: Ages spent discarding blocks that weren't used! |
| |
Hi.
On 04/08/10 22:44, Mark Lord wrote: > Looks to me like more and more things are using the block discard > functionality, and as predicted it is slowing things down enormously. > > The problem is that we still only discard tiny bits (a single range > still??) > per TRIM command, rather than batching larger ranges and larger numbers > of ranges into single TRIM commands. > > That's a very poor implementation, especially when things start enabling > it by default. Eg. the swap code, mke2fs, etc.. > > Ugh.
I was hoping for a nice quick and simple answer. Since I haven't got one, I'll try to find time to do a git bisect. I think I'll also look at the swap code more carefully and see if it's doing the sensible thing. I can't (at the moment) see the logic behind calling discard when allocating swap. At freeing time makes much more sense to me.
Regards,
Nigel
| |