Am 19.04.2021 um 19:12 hat Peter Lieven geschrieben: > > > Von meinem iPhone gesendet > > > Am 19.04.2021 um 14:31 schrieb Kevin Wolf <kw...@redhat.com>: > > > > Am 19.04.2021 um 11:13 hat Peter Lieven geschrieben: > >> > >> > >>>> Am 19.04.2021 um 10:36 schrieb Peter Lieven <p...@kamp.de>: > >>> > >>> > >>> > >>>> Am 15.04.2021 um 17:22 schrieb Kevin Wolf <kw...@redhat.com>: > >>>> > >>>> Peter, three years ago you changed 'qemu-img convert' to sacrifice some > >>>> sparsification in order to get aligned requests on the target image. At > >>>> the time, I thought the impact would be small, but it turns out that > >>>> this can end up wasting gigabytes of storagee (like converting a fully > >>>> zeroed 10 GB image taking 2.8 GB instead of a few kilobytes). > >>>> > >>>> https://bugzilla.redhat.com/show_bug.cgi?id=1882917 > >>>> > >>>> I'm not entirely sure how to attack this best since this is a tradeoff, > >>>> but maybe the approach in this series is still good enough for the case > >>>> that you wanted to fix back then? > >>>> > >>>> Of course, it would be possible to have a more complete fix like looking > >>>> forward a few blocks more before writing data, but that would probably > >>>> not be entirely trivial because you would have to merge blocks with ZERO > >>>> block status with DATA blocks that contain only zeros. I'm not sure if > >>>> it's worth this complication of the code. > >>> > >>> I will try to look into this asap. > >> > >> Besides from the reproducer described in the ticket, I retried my old > >> conversion test in our environment: > >> > >> Before commit 8dcd3c9b91: reads 4608 writes 14959 > >> After commit 8dcd3c9b91: reads 0 writes 14924 > >> With Kevins patch: reads 110 writes 14924 > >> > >> I think this is a good result if it avoids other issues. > > > > Sounds like a promising way to make the tradeoff. Thanks for testing! > > is this sth for 6.0-rc4?
No, certainly not. It would be for the first 6.1 pull request. Kevin
