On 06/18/2017 04:43 PM, Jeff Layton wrote: >>> Just checked, and creating a 1TB ram disk and then running mkfs.ext2 on it >>> writes 16851MiB of data. I can't say I'm surprised you OOM, if you run that >>> in a 8G VM, as you're about 8G short. >>> >>> I'm puzzled as to why the discard change would make any difference, however. >> >> Reverted the patch, and I see identical behavior. The only difference is that >> the whole device is trimmed first, as expected. But it still writes ~16G >> afterwards. >> >> Are you sure this commit is what broke things for you? Honestly, I don't see >> how it could ever work with 1TB ram disk, 8G of RAM, and 16G of data written. >> > > My mistake! My brd rd_size parameter was too large by a factor of 1024 > (I missed that it was in kbytes and not bytes). With it sanely sized to > 1G (as I had actually intended), it works fine. > > It's interesting that the older kernel survives this and the newer one > doesn't, but since it's such a pathological setup I'm not too worried > about it.
Beats me, I don't see how anything could make a 16G ram disk work on an 8G setup? If the above has any change in behavior, I'd be inclined to point at vm changes. Puzzled! -- Jens Axboe
