Messages in this thread | | | From | Daniel Phillips <> | Subject | Re: Linux/Pro -- clusters | Date | Tue, 4 Dec 2001 18:16:32 +0100 |
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On December 4, 2001 04:19 pm, Jeff Garzik wrote: > Daniel Phillips wrote: > > > > On December 4, 2001 03:09 am, Donald Becker wrote: > > > To bring this branch back on point: we should distinguish between > > > design for an arbitrary and unpredictable goal (e.g. 128 way SMP) > > > vs. putting some design into things that we are supposed to already > > > understan > > > [...] > > > a VFS layer that doesn't require the kernel to know a priori all of > > > the filesystem types that might be loaded > > > > Right, there's a consensus that the fs includes have to fixed and that it > > should be in 2.5.lownum. The precise plan isn't fully evolved yet ;) > > > > See fsdevel for the thread, 3-4 months ago. IIRC, the favored idea (Linus's) > > was to make the generic struct inode part of the fs-specific inode instead of > > the other way around, which resolves the question of how the compiler > > calculates the size/layout of an inode. > > > > This is going to be a pervasive change that someone has to do all in one > > day, so it remains to be seen when/if that is actually going to happen. > > > > It's also going to break every out-of-tree filesystem. > > ug. what's wrong with a single additional alloc for generic_ip? [if a > filesystem needs to do multiple allocs post-conversion, somebody's doing > something wrong]
Single additional alloc -> twice as many allocs, two slabs, more cachelines dirty. This was hashed out on fsdevel, though apparently not to everyone's satisfaction.
> Using generic_ip in its current form has the advantage of being able to > create a nicely-aligned kmem cache for your private inode data.
I don't see why that's hard with the combined struct.
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