ccd component partition. Note that the ccd driver still allows partitions
of any types as components since an on-disk BSD disklabel isn't available
on some port.
default, as the copyright on the main file (ffs_softdep.c) is such
that is has been put into gnusrc. options SOFTDEP will pull this
in. This code also contains the trickle syncer.
Bump version number to 1.4O
a fifo of component buffers, and free them if ccdbuffer() fails. Once
all component buffers are build, run through the fifo and fire off the
requests to the components.
better mirroring solution.
The ccd driver will stay, even in the presence of RAIDframe, for applications
where just RAID-0 is needed (much smaller code footprint).
- If the partition was previously open, don't do the open/close steps.
(Sync with other disk drivers.)
- foosize()'s return value is in DEV_BSIZE units; adjust the size obtained
from the disklabel accordingly.
- Keep a freelist of component buffer headers, defaulting
to 8 headers per component (tunable with the CCDNBUF
kernel compile option).
- When allocating a component buffer, try to pull a header
off the freelist first, falling back on MALLOC() if the
freelist is empty. Use MALLOC() rather than malloc(),
because it will attempt to short-cut the allocation before
actually making a full-blown malloc() call.
- Keep statistics on how many component buffer headers have
been allocated and how many of those allocations have
resulted in freelist misses.
With these changes, I observed measurable decreases in system and
wall clock time on operations on an 8G ccd, as well as a measurable
drop in the time spent in ccdbuffer() (measured with kernel profiling).
- New metrics handling. Metrics are now kept in the new
`struct disk'. Busy time is now stored as a timeval, and
transfer count in bytes.
- Storage for disklabels is now dynamically allocated, so that
the size of the disk structure is not machine-dependent.
- Several new functions for attaching and detaching disks, and
handling metrics calculation.
Old-style instrumentation is still supported in drivers that did it before.
However, old-style instrumentation is being deprecated, and will go away
once the userland utilities are updated for the new framework.
For usage and architectural details, see the forthcoming disk(9) manual
page.
enami