to buffered block devices are allowed. The default is to be backwards
compatible, i.e. reads and writes are allowed.
The idea is for a larger crowd to start running with this disabled and
see what problems, if any, crop up, and then to change the default to
off and see if any problems crop up in the next 6 months prior to
potentially removing support entirely. There are still a few people,
Julian and myself included, who believe the buffered block device
access from usermode to be useful.
Remove use of vnode->v_lastr from buffered block device I/O in
preparation for removal of vnode->v_lastr field, replacing it with
the already existing seqcount metric to detect sequential operation.
Reviewed by: Alan Cox <alc@cs.rice.edu>, David Greenman <dg@root.com>
previously issued synchronously even if async daemons (nfsiod's) were
available. The commit has been moved from the strategy code to the doio
code in order to asynchronize it.
Removed use of lastr in preparation for removal of vnode->v_lastr. It
has been replaced with seqcount, which is already supported by the system
and, in fact, gives us a better heuristic for sequential detection then
lastr ever did.
Made major performance improvements to the server side commit. The
server previously fsync'd the entire file for each commit rpc. The
server now bawrite()s only those buffers related to the offset/size
specified in the commit rpc.
Note that we do not commit the meta-data yet. This works still needs
to be done.
Note that a further optimization can be done (and has not yet been done)
on the client: we can merge multiple potential commit rpc's into a
single rpc with a greater file offset/size range and greatly reduce
rpc traffic.
Reviewed by: Alan Cox <alc@cs.rice.edu>, David Greenman <dg@root.com>
syncs the entire underlying file rather then just the requested range,
resulting in huge inefficiencies when the VM system is articulated in
a certain way. The VOP_FSYNC was also found to massively reduce NFS
performance in certain cases.
Change MADV_DONTNEED and MADV_FREE to call vm_page_dontneed() instead
of vm_page_deactivate(). Using vm_page_deactivate() causes all
inactive and cache pages to be recycled before the dontneed/free page
is recycled, effectively flushing our entire VM inactive & cache
queues continuously even if only a few pages are being actively MADV
free'd and reused (such as occurs with a sequential scan of a
memory-mapped file).
Reviewed by: Alan Cox <alc@cs.rice.edu>, David Greenman <dg@root.com>
from the vnode. (The changeover is undergoing final testing and
will be committed soon).
Reviewed by: Alan Cox <alc@cs.rice.edu>, David Greenman <dg@root.com>
size != 512 that are configured without a label. The bug should only
have effected swap-backed VN mounts without a label.
Add several major features to VN. In the kernel we add a swap
pre-reservation capability, which can be used to guarentee seek
consistency for swap-backed VN nodes. This also incidently allows
a swap-backed VN filesystem to be recovered after a crash in some
cases (if the same swap blocks happen to be reserved).
We also add a number of new options to vnconfig which do the work
of pre-zeroing or creating/truncating/extending a file which greatly
simplifies using VN in a file-backed configuration.
Add FreeBSD CVS label to sys/sys/vnioctl.h, as well as a new ioctl
flag for the swap pre-reservation feature.
Reviewed by: Alan Cox <alc@cs.rice.edu>, David Greenman <dg@root.com>
underlying physical sector size when aligning I/O transfer sizes.
It cannot assume 512 bytes.
We assume the underlying sector size is a power of 2. If it isn't,
mmap() will break badly anyway (in the same way mmap broke with NFS
when NFS tried to cache piecemeal write ranges in buffers, before
we enforced read-buffer-before-write-piecemeal for NFS).
Reviewed by: Alan Cox <alc@cs.rice.edu>, David Greenman <dg@root.com>
Swap space can be freed from an interrupt and so swap reservation and
freeing must occur at splvm.
Add swap_pager_reserve() code to support a new swap pre-reservation
capability for the VN device.
Generally cleanup the swap code by simplifying the swp_pager_meta_build()
static function and consolidating the SWAPBLK_NONE test from a bit test
to an absolute compare. The bit test was left over from a rejected
swap allocation scheme that was not ultimately committed. A few other
minor cleanups were also made.
Reorganize the swap strategy code, again for VN support, to not
reallocate swap when writing as this messes up pre-reservation and
can fragment I/O unnecessarily as VN-baesd disk is messed around with.
Reviewed by: Alan Cox <alc@cs.rice.edu>, David Greenman <dg@root.com>
current process from the exclusive lock prior to initiating I/O.
This fixes a panic related to swap-backed VN disks
Reviewed by: Alan Cox <alc@cs.rice.edu>, David Greenman <dg@root.com>
Replace various VM related page count calculations strewn over the
VM code with inlines to aid in readability and to reduce fragility
in the code where modules depend on the same test being performed
to properly sleep and wakeup.
Split out a portion of the page deactivation code into an inline
in vm_page.c to support vm_page_dontneed().
add vm_page_dontneed(), which handles the madvise MADV_DONTNEED
feature in a related commit coming up for vm_map.c/vm_object.c. This
code prevents degenerate cases where an essentially active page may
be rotated through a subset of the paging lists, resulting in premature
disposal.
what I was trying to do work much better (ie at all. I could have sworn
it was working...) Fix a SEEK_SET to be SEEK_CUR, and make Bruce's
lseek() test work correctly.
useful as a seeking-tool as well as its many other uses. Previously,
dd(1) would succeed with count=0, but wouldn't get to the point that
blocks were to be read/written. This is a more useful behavior, and
this specific case doesn't seem to be handled by POSIX.
It's GPL'ed of course, but looking over it tonight I learned of Yet Another
Fast EtherLink XL Adapter: the 3c980C server adapter. This is basically
an updated version of the 3c980 that uses the Tornado ASIC instead of the
earlier Hurricane ASIC. The only change here is to add the new PCI device
ID (0x9805) and corresponding table entries.
commit and those which cause ugly nroff output have been fixed, since
the purpose of the style guideline which they contravene is to reduce
the sizes of deltas.
Reported by: bde
