Handle case when ACPI reports HPET device, but does not provide memory
resource for it. In such case take the address range from the HPET table.
This fixes hpet(4) driver attach on Asrock C2750D4I board.
Use relaxed (write-only) memory barriers when writing some of queue index
registers (for now on ISP2400+). We never read those registers back and
AFAIK their semantics does not require any immediate reaction on write.
Some more registers access optimizations:
- Process ATIO queue only if interrupt status tells so;
- Do not update queue out pointers after each processed command, do it
only once at the end of the loop.
Save one more register read per command by not reading rqstoutrp register
every time. The purpose of that register is unlikely output queue overflow
detection, so read it only when its last known (and probably stale now)
value signals overflow.
Optimize isp(4) to reduce CPU usage, especially in target mode:
- Remove two excessive and slow register reads from isp_intr(). Instead
of rereading value every time, assume that registers contain what we have
written there.
- Avoid sequential search through 4096 array elements when looking for
command tag. Use hash of lists to store active tags separately from free
ones and so greatly speedup the searches.
Don't even try to read vdev labels from devices smaller then SPA_MINDEVSIZE
(64MB). Even if we would find one somehow, ZFS kernel code rejects such
devices. It is funny to look on attempts to read 4 256K vdev labels from
1.44MB floppy, though it is not very practical and quite slow.
Reenable vfs.zfs.zio.use_uma for amd64, disabled at r209261.
On machines with seveal CPUs and enough RAM this can easily twice improve
ZFS performance or twice reduce CPU usage. It was disabled three years
ago due to memory and KVA exhaustion reports, but our VM subsystem got
improved a lot since that time, hopefully enough to make another try.
Introduce allocation cache to store LZ4 compression contexts without kicking
VM subsystem twice for every written record.
Tests on 24-core system show double reduction of CPU time spent on copying
single large well-compressed file.
This patch is not really needed on illumos (while not harm either) since
their memory allocator by default uses caching for all requests up to 128K.
Make UMA to not blindly force offpage slab header allocation for large
(> PAGE_SIZE) zones. If zone is not multiple to PAGE_SIZE, there may
be enough space for the header at the last page, so we may avoid extra
header memory allocation and hash table update/lookup.
ZFS creates bunch of odd-sized UMA zones (5120, 6144, 7168, 10240, 14336).
This change gives good use to at least some of otherwise lost memory there.
Don't count bucket allocation failures for UMA zones as their own failures.
There are good reasons for this to happen, such as recursion prevention, etc.
and they are not fatal since buckets are just an optimization mechanism.
Real bucket allocation failures are any way counted by the bucket zones
themselves, and we don't need double accounting there.
Implement mechanism to safely but slowly purge UMA per-CPU caches.
This is a last resort for very low memory condition in case other measures
to free memory were ineffective. Sequentially cycle through all CPUs and
extract per-CPU cache buckets into zone cache from where they can be freed.
Grow UMA zone bucket size also on lock congestion during item free.
Lock congestion is the same, whether it happens on alloc or free, so
handle it equally. Now that we have back pressure, there is no problem
to grow buckets a bit faster. Any way growth is much slower then in 9.x.
Add two new UMA bucket zones to store 3 and 9 items per bucket.
These new buckets make bucket size self-tuning more soft and precise.
Without them there are buckets for 1, 5, 13, 29, ... items. While at
bigger sizes difference about 2x is fine, at smallest ones it is 5x and
2.6x respectively. New buckets make that line look like 1, 3, 5, 9, 13,
29, reducing jumps between steps, making algorithm work softer, allocating
and freeing memory in better fitting chunks. Otherwise there is quite a
big gap between allocating 128K and 5x128K of RAM at once.
Implement soft pressure on UMA cache bucket sizes.
Every time system detects low memory condition decrease bucket sizes for
each zone by one item. As result, higher memory pressure will push to
smaller bucket sizes and so smaller per-CPU caches and so more efficient
memory use.
Before this change there was no force to oppose buckets growth as result
of practically inevitable zone lock conflicts, and after some run time
per-CPU caches could consume enough RAM to kill the system.
Create own free list for each of the first 32 possible allocation sizes.
In case of 4K allocation quantum that means for allocations up to 128K.
With growth of memory fragmentation these lists may grow to quite a large
sizes (tenths and hundreds of thousands items). Having in one list items
of different sizes in worst case may require full linear list traversal,
that may be very expensive. Having lists for items of single size means
that unless user specify some alignment or border requirements (that are
very rare cases) first item found on the list should satisfy the request.
While running SPEC NFS benchmark on top of ZFS on 24-core machine with
84GB RAM this change reduces CPU time spent in vmem_xalloc() from 8%
and lock congestion spinning around it from 20% to invisible levels.
And that all is by the cost of just 26 more pointers per vmem instance.
If at some point our kernel will start to actively use KVA allocations
with odd sizes above 128K, something may need to be done to bigger lists
also.
For sys/boot/i386 and sys/boot/pc98, separate flags to be passed
directly to the linker (LD_FLAGS) from flags passed indirectly, via the
compiler driver (LDFLAGS).
This is because several Makefiles under sys/boot/i386 and sys/boot/pc98
use ${LD} directly to link, and the normal LDFLAGS value should not be
used in these cases.
In sys/dev/scc, remove unused static function scc_setmreg(). While
here, invoke scc_getmreg() in two more places where it can be used.
Reviewed by: marcel
Fix bug introduced at r252226, when udata argument passed to bucket_alloc()
was used without making sure first that it was really passed for us.
On some of my systems this bug made user argument passed by ZFS code to
uma_zalloc_arg() unexpectedly block UMA per-CPU caches for those zones.
In sys/dev/mcd/mcd.c, mark the static const COPYRIGHT string as __used,
so it ends up in the object file, and no warnings are emitted about it
being actually unused.
For sys/dev/drm2/radeon, only use -fms-extensions with gcc. This flag
is only to stop gcc complaining about anonymous unions, which clang does
not do. For clang 3.4 however, -fms-extensions enables the Microsoft
__wchar_t type, which clashes with our own types.h.
MFC r260102:
Similar to r260020, only use -fms-extensions with gcc, for all other
modules which require this flag to compile. Use a GCC_MS_EXTENSIONS
variable, defined in kern.pre.mk, which can be used to easily supply the
flag (or not), depending on the compiler type.
In libc++'s type_traits header, avoid warnings (activated by our use of
-Wsystem-headers) about potential keyword compatibility problems, by
adding a __libcpp prefix to the applicable identifiers.
Upstream is still debating about this, but we need it now, to be able to
import clang 3.4.
