On Thu, 2007-11-15 at 20:37 +0100, Miklos Szeredi wrote: > > I'm somewhat confused by the complexity. Currently we can already have a > > lot of dirty pages from FUSE (up to the per BDI dirty limit - so > > basically up to the total dirty limit). > > > > How is having them dirty from mmap'ed writes different? > > Nope, fuse never had dirty pages. It does normal writes > synchronously, just updating the cache. > > The dirty accounting and then the per-bdi throttling basically made it > possible _at_all_ to have a chance at a writepage implementation which > is not deadlocky (so thanks for those ;). > > But there's still the throttle_vm_writeout() thing, and the other > places where the kernel is waiting for a write to complete, which just > cannot be done within a constrained time if an unprivileged userspace > process is involved. Ah, ok, your initial story missed this part (not being intimately familiar with FUSE made all that somewhat obscure). The next point then, I'd expect your fuse_page_mkwrite() to push writeout of your 32-odd mmap pages instead of poll. - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
