Messages in this thread | | | Date | Mon, 27 Mar 2000 08:06:11 -0700 | From | "Jeff V. Merkey" <> | Subject | Re: NWFS Source Code Posted at 207.109.151.240 |
| |
Andi,
The Linux Buffer Cache does not present a logical block cache for NetWare's flavor of mirroring support, although basically what's there is implemented as a Logical Block Cache on top of the Linux Buffer Cache. You will notice that NWFS can use either it's own LRU or the linux buffer cache (there's an #if/#else/#endif for LINUX_BUFFER_CACHE in block.c -- this will make NWFS sit on top of buffer.c). You would want to crank down the MAX_BLOCK_BUFFERS count in nwfs.h to something smaller than 2000.
The Async processes bascially provides an elevator for remirroring and concurrent mirroring I/O so the file system doesn't get starved. It sits on top of the linux disk interface. These abstractions are also necessary for our clustered file system for Linux (M2FS). Look carefully at the layering in nwvp.c, and it will be clear why we did what we did.
This code base also runs on several other platforms, and some of what is there is not applicable to Linux, but is to NT and DOS. The tools use these interfaces and we have to have them as convinient abstractions since they are not available on every platform (not all OS's are as blessed as Linux).
What's here is a smaller version of the internal architecture of Native NetWare. Some of the services and what they do is a little different. I hope we are helping Linux?
Very Truly Yours,
Jeff
Andi Kleen wrote: > > "Jeff V. Merkey" <jmerkey@timpanogas.com> writes: > > > > 1. Full Asynch IO Manager (SMP) > > Could you expand a bit on your reasons to use an own buffer cache > instead of the standard Linux one ? Also what does this async > manager offer over the normal asynchronous block device interface ? > > Thanks, > > -Andi > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.rutgers.edu > Please read the FAQ at http://www.tux.org/lkml/
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |