Am Sonntag, 7. Oktober 2012 schrieb Alex Lyakas: > On Sun, Oct 7, 2012 at 12:53 PM, Martin Steigerwald <mar...@lichtvoll.de> wrote: > > Am Sonntag, 7. Oktober 2012 schrieb Alex Lyakas: […] > >> On Sat, Oct 6, 2012 at 11:40 AM, Martin Steigerwald > > > > <mar...@lichtvoll.de> wrote: > >> > Am Donnerstag, 4. Oktober 2012 schrieb Alex Lyakas: > >> >> Hi Jan, > >> >> as I promised, here is some code for you to look at. > >> >> > >> >> First I will describe the approach in general. > >> >> > >> >> # Get rid of the pipe. Instead, user-space passes a buffer and > >> >> kernel fills the specified user-space buffer with commands. > >> >> # When the buffer is full, kernel stops generating commands and > >> >> returns a checkpoint to the user-space. > >> > > >> > Can it just fill a second buffer while userspace command handles > >> > the first? > >> > >> No, at this point kernel receives only one buffer and fills it up. > >> Can you pls elaborate more what improvement you have in mind? Like > >> user-space sending a list of buffers to the kernel in one shot? Or > >> that user-space handles kind of producer-consumer pool of buffers > >> and works on full buffers while kernel fills the empty ones (this, > >> of course, can work). > >> > >> In general, my direction was to make the kernel call stateless, > >> which makes the user-space part more flexible. > > > > Hmmm, okay. So the kernel has only one buffer. > > > > Well I had some kind of double buffering in mind. The kernel fills > > one buffer while the userspace application handles the other buffer. > > Then kernel and userspace swap buffers. > > > > Just an idea of mine. I do not do kernel development, so I do not > > know whether its feasible. Was happy enough that I wrote a C program > > that uses some kernel functions some weeks ago that actually worked > > :) > > > > So would using two buffers and swapping them make sense?
> Martin, > I apologize for misspelling your name. No problem. > Yes, user-space can handle a buffer pool of any number of buffers, > like one thread fetching a free buffer, handling it to the kernel, > then putting it on some ready-buffer queue and signalling to a another > thread that fetches ready (full) buffers and handles them. After it is > done with the buffer, it puts it back on a free-buffer queue and > signals the first thread. This is exactly producer-consumer. Ah, so the kernel does not need to have anything to do with it. Nice. Thanks, -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
