DTrace's pid provider works by inserting breakpoint instructions at probe
sites and installing a hook at the kernel's trap handler. The fasttrap code
will emulate the overwritten instruction in some common cases, but otherwise
copies it out into some scratch space in the traced process' address space
and ensures that it's executed after returning from the trap.
In Solaris and illumos, this (per-thread) scratch space comes from some
reserved space in TLS, accessible via the fs segment register. This
approach is somewhat unappealing on FreeBSD since it would require some
modifications to rtld and jemalloc (for static TLS) to ensure that TLS is
executable, and would thus introduce dependencies on their implementation
details. I think it would also be impossible to safely trace static binaries
compiled without these modifications.
This change implements the functionality in a different way, by having
fasttrap map pages into the target process' address space on demand. Each
page is divided into 64-byte chunks for use by individual threads, and
fasttrap's process descriptor struct has been extended to keep track of
any scratch space allocated for the corresponding process.
With this change it's possible to trace all libc functions in a program,
e.g. with
pid$target:libc.so.*::entry {@[probefunc] = count();}
Previously this would generally cause the victim process to crash, as
tracing memcpy on amd64 requires the functionality described above.
Increase maximal number of SCSI ports in CTL from 32 to 128.
After I gave each iSCSI target its own port, the old limit appeared to be
not so big. This change almost proportionally increases per-LUN memory
use, but it is still three times better then it was before r268807.
Reduce per-LUN memory usage from 18MB to 1.8MB.
CTL never had use for CA support code since SPI has gone, and there is no
even frontends supporting that. But it still was reserving 256 bytes of
memory per LUN per every possible initiator on every possible port.
Wrap unused code with ifdef's in case somebody ever need it.
Add support for VMWare dialect of EXTENDED COPY command, aka VAAI Clone.
This allows to clone VMs and move them between LUNs inside one storage
host without generating extra network traffic to the initiator and back,
and without being limited by network bandwidth.
LUNs participating in copy operation should have UNIQUE NAA or EUI IDs set.
For LUNs without these IDs VMWare will use traditional copy operations.
Beware: the above LUN IDs explicitly set to values non-unique from the VM
cluster point of view may cause data corruption if wrong LUN is addressed!
Sponsored by: iXsystems, Inc.
Move the "retry:" label so that the calls to m_pullup() are
not done after the call to m_defrag(). This fixes a problem
where m_pullup() would prepend an mbuf to the list created
by m_defrag() making the chain greater than 32 again.
Only invoke fasttrap hooks for traps from user mode, and ensure that they're
called with interrupts enabled. Calling fasttrap_pid_probe() with interrupts
disabled can lead to deadlock if fasttrap writes to the process' address
space.
When our linker merges .SUNW_dof sections from multiple files, it simply
concatenates the DOF tables into one section. Previously, the USDT init
code in drti.o would only look at the first table in the DOF section; with
this change, it iterates over all the tables, passing each DOF table to
the kernel.
PR: 186821
Copying pages via temporary mappings in the !DMAP case of pmap_copy_pages()
involves updating the corresponding page tables followed by accesses to the
pages in question. This sequence is subject to the situation exactly described
in the "AMD64 Architecture Programmer's Manual Volume 2: System Programming"
rev. 3.23, "7.3.1 Special Coherency Considerations" [1, p. 171 f.]. Therefore,
issuing the INVLPG right after modifying the PTE bits is crucial (see also
r269050, MFCed to stable/10 in r269235).
For the amd64 PMAP code, the order of instructions was already correct. The
above fact still is worth documenting, though.
1: http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2012/10/24593_APM_v21.pdf
Reviewed by: alc
Sponsored by: Bally Wulff Games & Entertainment GmbH
- Copying and zeroing pages via temporary mappings involves updating the
corresponding page tables followed by accesses to the pages in question.
This sequence is subject to the situation exactly described in the "AMD64
Architecture Programmer's Manual Volume 2: System Programming" rev. 3.23,
"7.3.1 Special Coherency Considerations" [1, p. 171 f.]. Therefore, issuing
the INVLPG right after modifying the PTE bits is crucial.
For pmap_copy_page(), this has been broken in r124956 and later on carried
over to pmap_copy_pages() derived from the former, while all other places
in the i386 PMAP code use the correct order of instructions in this regard.
Fixing the latter breakage solves the problem of data corruption seen with
unmapped I/O enabled when running at least bare metal on AMD R-268D APUs.
However, this might also fix similar corruption reported for virtualized
environments.
- In pmap_copy_pages(), correctly set the cache bits on the source page being
copied. This change is thought to be a NOP for the real world, though. [2]
1: http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2012/10/24593_APM_v21.pdf
Submitted by: kib [2]
Reviewed by: alc, kib
Sponsored by: Bally Wulff Games & Entertainment GmbH
Don't save entropy inside jails.
As of r126744, we no longer feed the entropy device in jails upon
start, and collecting them is no longer useful.
PR: conf/126744
Submitted by: Eugene Grosbein <eugen grosbein net> (with minor changes)
Approved by: so (des)
Improve extreme rewind import.
When doing an "extreme rewind" import ("zpool import -XF"), we attempt
to verify all data in the pool, essentially scrubbing the entire pool.
The problem is that spa_load_verify_cb() issues an unbounded number of
concurrent scrub i/os. This can lead to all of memory being used for
these zio's, wedging the system. Like normal scrub, we need to put a
cap on the number of outstanding i/os, and have the traverse thread
block when we reach this cap.
For this purpose the cap can be very large (10,000) to optimize the
elevator algorithm. Three kernel tunables have been added:
vfs.zfs.spa_load_verify_maxinflight
vfs.zfs.spa_load_verify_metadata
vfs.zfs.spa_load_verify_data
The latter two tunables controls whether metadata and/or user data
when doing extreme rewind.
Make 'zpool import -T' imply scrub.
Make zpool import -T <txg> accept hexadecimal values for the txg when
prefixed with 0x.
Skip txg's for which there is no uberblock when doing extreme rewind.
Skip reading all user data twice by skipping prefetches when doing
extreme rewinds as we do not access via the ARC.
Illumos issues:
4970 need controls on i/o issued by zpool import -XF
4971 zpool import -T should accept hex values
4972 zpool import -T implies extreme rewind, and thus a scrub
4973 spa_load_retry retries the same txg
4974 spa_load_verify() reads all data twice
Fix ctl(4) kldload failure that manifested like this:
link_elf_obj: symbol icl_pdu_new_bhs undefined
PR: 192031
Submitted by: Nils Beyer (earlier version)
Sponsored by: FreeBSD Foundation
This brings VHD support to mkimg(1); both dynamic and fixed file formats.
Dynamic VHD and VMDK file images are now sparsely written, meaning that
"free" sectors do not occupy space.
Relnotes: yes
Add OBJ_TMPFS_NODE flag.
MFC r268616:
Set the OBJ_TMPFS_NODE flag for vm_object of VREG tmpfs node.
MFC r269053:
Correct assertion. tmpfs vm object is always at the bottom of
the shadow chain.
Generalize vn_get_ino() to allow filesystems to use custom vnode
producer. Convert inline copies of vn_get_ino() in msdosfs and cd9660
into the uses of vn_get_ino_gen().
Pending interrupt status is cleared by writing to the ISR, not the data reg.
Use named constant rather than '0' to access the reset controller register.
