modeled on the access cache found in NFS, smbfs, and the Linux coda
module. This is a positive access cache of a single entry per file,
tracking recently granted rights, but unlike NFS and smbfs,
supporting explicit invalidation by the distributed file system.
For each cnode, maintain a C_ACCCACHE flag indicating the validity
of the cache, and a cached uid and mode tracking recently granted
positive access control decisions.
Prefer the cache to venus_access() in VOP_ACCESS() if it is valid,
and when we must fall back to venus_access(), update the cache.
Allow Venus to clear the access cache, either the whole cache on
CODA_FLUSH, or just entries for a specific uid on CODA_PURGEUSER.
Unlike the Coda module on Linux, we don't flush all entries on a
user purge using a generation number, we instead walk present
cnodes and clear only entries for the specific user, meaning it is
somewhat more expensive but won't hit all users.
Since the Coda module is agressive about not keeping around
unopened cnodes, the utility of the cache is somewhat limited for
files, but works will for directories. We should make Coda less
agressive about GCing cnodes in VOP_INACTIVE() in order to improve
the effectiveness of in-kernel caching of attributes and access
rights.
MFC after: 1 month
VFS namecache, as is done by the Coda module on Linux. Unlike the Coda
namecache, the global VFS namecache isn't tagged by credential, so use
ore conservative flushing behavior (for now) when CODA_PURGEUSER is
issued by Venus.
This improves overall integration with the FreeBSD VFS, including
allowing __getcwd() to work better, procfs/procstat monitoring, and so
on. This improves shell behavior in many cases, and improves ".."
handling. It may lead to some slowdown until we've implemented a
specific access cache, which should net improve performance, but in the
mean time, lookup access control now always goes to Venus, whereas
previously it didn't.
MFC after: 1 month
When ntfs_ntput() reaches 0 in the refcount the inode lockmgr is not
released and directly destroyed. Fix this by unlocking the lockmgr() even
in the case of zero-refcount.
Reported by: dougb, yar, Scot Hetzel <swhetzel at gmail dot com>
Submitted by: yar
This has the side effect of confusing gcc-4.2.1's optimizer into more
often doing the right thing. When it does the wrong thing here, it
seems to be mainly making too many copies of x with dependency chains.
This effect is tiny on amd64, but in some cases on i386 it is enormous.
E.g., on i386 (A64) with -O1, the current version of exp2() should
take about 50 cycles, but took 83 cycles before this change and 66
cycles after this change. exp2f() with -O1 only speeded up from 51
to 47 cycles. (exp2f() should take about 40 cycles, on an Athlon in
either i386 or amd64 mode, and now takes 42 on amd64). exp2l() with
-O1 slowed down from 155 cycles to 123 for some args; this is unimportant
since the i386 exp2l() is a fake; the wrong thing for it seems to
involve branch misprediction.
faster on all machines tested (old Celeron (P2), A64 (amd64 and i386)
and ia64) except on ia64 when compiled with -O1. It takes 2 more
multiplications, so it will be slower on old machines. The speedup
is about 8 cycles = 17% on A64 (amd64 and i386) with best CFLAGS
and some parallelism in the caller.
Move the evaluation of 2**k up a bit so that it doesn't compete too
much with the new polynomial evaluation. Unlike the previous
optimization, this rearrangement cannot change the result, so compilers
and CPU schedulers can do it, but they don't do it quite right yet.
This saves a whole 1 or 2 cycles on A64.
- mention LRO support
- describe multi-slice related tunables.
- correct DIAGNOSTICS section to reflect that missing firmware
is non-fatal.
Submitted by: gallatin
nfs_xid_gen() function instead of duplicating the logic in both
nfsm_rpchead() and the NFS3ERR_JUKEBOX handling in nfs_request().
MFC after: 1 week
Submitted by: mohans (a long while ago)
through the FreeBSD ABI. IPC_INFO, SHM_INFO, SHM_STAT were added
specifically for Linux binary support. They are not documented
as being a part of the FreeBSD ABI, also, the structures necessary
for them have been hidden away from the users for a long time.
Also, the Linux ABI layer uses it's own structures to populate the
responses back to the user to ensure that the ABI is consistent.
I think there is a bit more separation work that needs to happen.
Reviewed by: jhb
Discussed with: jhb
Discussed on: freebsd-arch@ (very briefly)
MFC after: 1 month
the PIC also informs the platform at which IRQ level it can start
assigning IPIs, since this can depend on the number of IRQs
supported for external interrupts.
when the result is +-0. IEEE754 requires (in all rounding modes) that
if the result is +-0 then its sign is the same as that of the first
arg, but in round-towards-minus-infinity mode an uncorrected implementation
detail always reversed the sign. (The detail is that x-x with x's
sign positive gives -0 in this mode only, but the algorithm assumed
that x-x always has positive sign for such x.)
remquo() and remquof() seem to need the same fix, but I cannot test them
yet.
Use long doubles when mixing NaN args. This trick improves consistency
of results on at least amd64, so that more serious problems like the
above aren't hidden in simple regression tests by noise for the NaNs.
On amd64, hardware remainder should be used since it is about 10 times
faster than software remainder and is already used for remquo(), but
it involves using the i387 even for floats and doubles, and the i387
does NaN mixing which is better than but inconsistent with SSE NaN mixing.
Software remainder() would probably have been inconsistent with
software remainderl() for the same reason if the latter existed.
Signaling NaNs cause further inconsistencies on at least ia64 and i386.
Use __FBSDID().
PAGE_SIZE or less, the bounce page counting logic was flawed and wouldn't
reserve any pages. Adjust to be correct. Review of other architectures is
forthcoming.
Submitted by: Joseph Golio
With write-allocate cache we get into the following scenario:
1. data has been updated in the memory by the USB HC, but
2. D-cache holds an un-flushed value of it
3. when affected cache line is being replaced, the old (un-flushed) value is
flushed and overwrites the newly arrived
This is possible due to how write-allocate works with virtual caches (ARM for
example).
In case of USB transfers it leads to fatal tags discrepancies in umass(4)
operation, which look like the following:
umass0: Invalid CSW: tag 1 should be 2
(probe0:umass-sim0:0:0:0): Request completed with CAM_REQ_CMP_ERR
(probe0:umass-sim0:0:0:0): Retrying Command
umass0: Invalid CSW: tag 1 should be 3
(probe0:umass-sim0:0:0:0): Request completed with CAM_REQ_CMP_ERR
(probe0:umass-sim0:0:0:0): Retrying Command
umass0: Invalid CSW: tag 1 should be 4
(probe0:umass-sim0:0:0:0): Request completed with CAM_REQ_CMP_ERR
(probe0:umass-sim0:0:0:0): Retrying Command
umass0: Invalid CSW: tag 1 should be 5
(probe0:umass-sim0:0:0:0): Request completed with CAM_REQ_CMP_ERR
(probe0:umass-sim0:0:0:0): Retrying Command
umass0: Invalid CSW: tag 1 should be 6
(probe0:umass-sim0:0:0:0): Request completed with CAM_REQ_CMP_ERR
(probe0:umass-sim0:0:0:0): error 5
(probe0:umass-sim0:0:0:0): Retries Exausted
To eliminate this, a BUS_DMASYNC_PREREAD sync operation is required in
usbd_start_transfer().
Credits for nailing this down go to Grzegorz Bernacki gjb AT semihalf DOT com.
Reviewed by: imp
Approved by: cognet (mentor)
historical relic, and are no longer appropriate for either LAN or WAN
mounting. At modern (gigabit and 10 gigabit) LAN speeds packet loss
from socket buffer fill events is common, and sequence numbers wrap
quickly enough that data corruption is possible. TCP solves both of
these problems without imposing significant overhead.
MFC after: 1 month
sectors so the geometry of large IDE disks has to be adjusted. This
corresponds to what the OpenSolaris dad(7D) driver does except that
the latter only tweaks sectors and effectively limits the mediasize
to 128GB so the cylinders and heads fields won't ever overflow. Not
limiting the mediasize is a compromise between allowing to use Sun
disk label as far as possible and being able to use the entire disk
with another disk label.
This allows to use the full capacity of large IDE disks if they were
not labeled under (Open)Solaris (in both ways of the meaning).
MFC after: 2 weeks
Turn off TFTP support by default: when both TFTP and NFS are enabled in the
loader, strange interactions occur in the pure netbooting scenario (i.e.
loader is TFTP-ed, kernel+world mounted over NFS), leading to very slow access
to the NFS-exported files.
Reviewed by: grehan
Approved by: cognet (mentor)
exp2(i/TBLSIZE) * p(z) instead of only for the final multiplication
and addition. This fixes the code to match the comment that the maximum
error is 0.5010 ulps (except on machines that evaluate float expressions
in extra precision, e.g., i386's, where the evaluation was already
in extra precision).
Fix and expand the comment about use of double precision.
The relative roundoff error from evaluating p(z) in non-extra precision
was about 16 times larger than in exp2() because the interval length
is 16 times smaller. Its maximum was at least P1 * (1.0 ulps) *
max(|z|) ~= log(2) * 1.0 * 1/32 ~= 0.0217 ulps (1.0 ulps from the
addition in (1 + P1*z) with a cancelation error when z ~= -1/32). The
actual final maximum was 0.5313 ulps, of which 0.0303 ulps must have
come from the additional roundoff error in p(z). I can't explain why
the additional roundoff error was almost 3/2 times larger than the rough
estimate.
