The vnode-backed md(4) has to map the unmapped bio because VOP_READ()
and VOP_WRITE() interfaces do not allow to pass unmapped requests to
the filesystem. Vnode-backed md(4) uses pbufs instead of relying on
the bio_transient_map, to avoid usual md deadlock.
Sponsored by: The FreeBSD Foundation
Tested by: pho, scottl
buffer, transparently handling mapped or unmapped buffers. Its intent
is to replace the use of bzero(bp->b_data) in cases where the buffer
might be unmapped, to avoid unneeded upgrades.
Sponsored by: The FreeBSD Foundation
Tested by: pho
do not map the b_pages pages into buffer_map KVA. The use of the
unmapped buffers eliminate the need to perform TLB shootdown for
mapping on the buffer creation and reuse, greatly reducing the amount
of IPIs for shootdown on big-SMP machines and eliminating up to 25-30%
of the system time on i/o intensive workloads.
The unmapped buffer should be explicitely requested by the GB_UNMAPPED
flag by the consumer. For unmapped buffer, no KVA reservation is
performed at all. The consumer might request unmapped buffer which
does have a KVA reserve, to manually map it without recursing into
buffer cache and blocking, with the GB_KVAALLOC flag.
When the mapped buffer is requested and unmapped buffer already
exists, the cache performs an upgrade, possibly reusing the KVA
reservation.
Unmapped buffer is translated into unmapped bio in g_vfs_strategy().
Unmapped bio carry a pointer to the vm_page_t array, offset and length
instead of the data pointer. The provider which processes the bio
should explicitely specify a readiness to accept unmapped bio,
otherwise g_down geom thread performs the transient upgrade of the bio
request by mapping the pages into the new bio_transient_map KVA
submap.
The bio_transient_map submap claims up to 10% of the buffer map, and
the total buffer_map + bio_transient_map KVA usage stays the
same. Still, it could be manually tuned by kern.bio_transient_maxcnt
tunable, in the units of the transient mappings. Eventually, the
bio_transient_map could be removed after all geom classes and drivers
can accept unmapped i/o requests.
Unmapped support can be turned off by the vfs.unmapped_buf_allowed
tunable, disabling which makes the buffer (or cluster) creation
requests to ignore GB_UNMAPPED and GB_KVAALLOC flags. Unmapped
buffers are only enabled by default on the architectures where
pmap_copy_page() was implemented and tested.
In the rework, filesystem metadata is not the subject to maxbufspace
limit anymore. Since the metadata buffers are always mapped, the
buffers still have to fit into the buffer map, which provides a
reasonable (but practically unreachable) upper bound on it. The
non-metadata buffer allocations, both mapped and unmapped, is
accounted against maxbufspace, as before. Effectively, this means that
the maxbufspace is forced on mapped and unmapped buffers separately.
The pre-patch bufspace limiting code did not worked, because
buffer_map fragmentation does not allow the limit to be reached.
By Jeff Roberson request, the getnewbuf() function was split into
smaller single-purpose functions.
Sponsored by: The FreeBSD Foundation
Discussed with: jeff (previous version)
Tested by: pho, scottl (previous version), jhb, bf
MFC after: 2 weeks
breadn_flags(). Comparing with bread(), it adds an argument to pass
the flags to getblk().
Sponsored by: The FreeBSD Foundation
Tested by: pho
MFC after: 2 weeks
In common configurations biosize is a power of two, but is not required to
be so. Thanks to markj@ for spotting an additional case beyond my original
patch.
Reviewed by: rmacklem@
space configured for rc.d/dumpon to designate for dumping -- then exit
silently rather than with a
> realpath: /dev/dumpdev: No such file or directory
error message.
An argument could be made that we should print a (more informative) warning
message; but given that under the same conditions the rc.d/dumpon script will
already print a
> No suitable dump device was found
warning, it seems that printing an additional
> Dump device does not exist. Savecore not run.
warning would be superfluous.
first position of compatible property, so simplebus driver can be generic
driver for any bus listed as compatible with "simple-bus".
Sponsored by: The FreeBSD Foundation
command line option "-m <memsize in MB>" to specify the memory size.
Prior to this change the user needed to explicitly specify the amount of
memory allocated below 4G (-m <lowmem>) and the amount above 4G (-M <highmem>).
The "-M" option is no longer supported by 'bhyveload' and 'bhyve'.
The start of the PCI hole is fixed at 3GB and cannot be directly changed
using command line options. However it is still possible to change this in
special circumstances via the 'vm_set_lowmem_limit()' API provided by
libvmmapi.
Submitted by: Dinakar Medavaram (initial version)
Reviewed by: grehan
Obtained from: NetApp
to specify the offset into the PCI memory spare at which each serial port
will find its registers. This was already done for other Exar PCI serial
devices; it was accidentally omitted for this specific device.
Sponsored by: Sandvine Incorporated
MFC after: 1 week
calls to toggle TDF_SBDRY rather than passing PBDRY to individual sleep
calls.
- Remove the stop_allowed parameters from cursig() and issignal().
issignal() checks TDF_SBDRY directly.
- Remove the PBDRY and SLEEPQ_STOP_ON_BDRY flags.
has been deprecated for a while, some people still use it and were
unpleasantly surprised by this change.
I may revert this commit at a later date if I can come up with a way
to give users who still have authorized_keys2 files sufficient advance
warning.
MFC after: ASAP
register added to the symbol table by the assembler. On further
investigation it was found the problem was with the my_get_expression
function. This is called by parse_big_immediate.
Fix this by moving the call to parse_big_immediate to the end of the if,
else if, ..., else block.
much of which is not necessary for PowerPC.
The FBT module can likely be factored into 3 separate files: common,
intel, and powerpc, rather than duplicating most of the code between
the x86 and PowerPC flavors.
All DTrace modules for PowerPC will be MFC'd together once Fasttrap is
completed.
driver such that checking against the type was always false.
To detect NS DP83816, driver should have checked silicon revision
register for NS controllers. While here, remove SIS_TYPE_83816 to
not make the similar mistake again.
Reported by: Brad Smith ( brad@openbsd )
Replace the per-object resident and cached pages splay tree with a
path-compressed multi-digit radix trie.
Along with this, switch also the x86-specific handling of idle page
tables to using the radix trie.
This change is supposed to do the following:
- Allowing the acquisition of read locking for lookup operations of the
resident/cached pages collections as the per-vm_page_t splay iterators
are now removed.
- Increase the scalability of the operations on the page collections.
The radix trie does rely on the consumers locking to ensure atomicity of
its operations. In order to avoid deadlocks the bisection nodes are
pre-allocated in the UMA zone. This can be done safely because the
algorithm needs at maximum one new node per insert which means the
maximum number of the desired nodes is the number of available physical
frames themselves. However, not all the times a new bisection node is
really needed.
The radix trie implements path-compression because UFS indirect blocks
can lead to several objects with a very sparse trie, increasing the number
of levels to usually scan. It also helps in the nodes pre-fetching by
introducing the single node per-insert property.
This code is not generalized (yet) because of the possible loss of
performance by having much of the sizes in play configurable.
However, efforts to make this code more general and then reusable in
further different consumers might be really done.
The only KPI change is the removal of the function vm_page_splay() which
is now reaped.
The only KBI change, instead, is the removal of the left/right iterators
from struct vm_page, which are now reaped.
Further technical notes broken into mealpieces can be retrieved from the
svn branch:
http://svn.freebsd.org/base/user/attilio/vmcontention/
Sponsored by: EMC / Isilon storage division
In collaboration with: alc, jeff
Tested by: flo, pho, jhb, davide
Tested by: ian (arm)
Tested by: andreast (powerpc)
