On Mon, Aug 11, 2025 at 8:26 PM Chunsheng Luo <luochunsheng@xxxxxxxx> wrote: > > On Mon, Aug 11, 2025 Joanne Koong <joannelkoong@xxxxxxxxx> wrote: > >> > >> Large folios are only enabled if the writeback cache isn't on. > >> (Strictlimiting needs to be turned off if the writeback cache is used in > >> conjunction with large folios, else this tanks performance.) > > > > Some ideas for having this work with the writeback cache are > > a) add a fuse sysctl sysadmins can set to turn off strictlimiting for > > all fuse servers mounted after, in the kernel turn on large folios for > > writeback if that sysctl is on > > b) if the fuse server is privileged automatically turn off > > strictlimiting and enable large folios for writeback > > > > Any thoughts? > > Should large folios be enabled based on mount options? Consider adding an > option in fuse_init_out to explicitly turn on large folios. > Hi Chunsheng, Personally I'm not a fan of doing it through the init request because it is tied hand-in-hand with disabling strictlimiting (which requires admin privileges) and imo a) it feels clunky that the user needs to opt into it for writeback (for non-writeback cases, ideally large folios are the status quo) and then also find the bdi that corresponds to that fuse mount, then go into /sys/class/bdi/* for that bdi to disable strictlimiting, all while making sure this happens before write workloads start b) I think users (who most are not familiar with kernel internals) will likely be confused by what large folios are and whether/when they should opt into it or not imo if the fuse server is mounted as a privileged server, I think it's reasonable that strictlimiting could be turned off by default. Thanks, Joanne > Thanks > Chunsheng Luo
