Mike Snitzer [Tue, 19 Mar 2013 23:32:57 +0000 (10:32 +1100)]
When reading the dm cache metadata from disk, ignore the policy hints
unless they were generated by the same major version number of the same
policy module.
The hints are considered to be private data belonging to the specific
module that generated them and there is no requirement for them to make
sense to different versions of the policy that generated them.
Policy modules are all required to work fine if no previous hints are
supplied (or if existing hints are lost).
Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Mike Snitzer [Tue, 19 Mar 2013 23:32:57 +0000 (10:32 +1100)]
Separate dm cache policy version string into 3 unsigned numbers
corresponding to major, minor and patchlevel and store them at the end
of the on-disk metadata so we know which version of the policy generated
the hints in case a future version wants to use them differently.
Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Paul Bolle [Tue, 5 Mar 2013 13:59:23 +0000 (14:59 +0100)]
Change "select DMAR" to "select INTEL_IOMMU"
Commit d3f138106b ("iommu: Rename the DMAR and INTR_REMAP config
options") changed all references to DMAR in Kconfig files to INTEL_IOMMU
(and, likewise, changed the references to CONFIG_DMAR everywhere else
to CONFIG_INTEL_IOMMU). That commit missed one "select DMAR" statement
in ia64's Kconfig file. Change that one too.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Tony Luck <tony.luck@intel.com>
The list of output registers is
: "=r"(ret) : "r"(iha), "r"(pte):"memory");
The constraint "=r" means that the GCC has to maintain that these vars
are in registers and contain valid info when the program flow leaves
the assembly block (output registers).
But "=r" also means that GCC can put them in registers that are used
as input registers. Input registers are iha, pte on the example.
If the predicate p7 is true, the 8th assembly instruction
"(p7) mov %0=r0;"
is the first one which writes to a register which is maintained by the
register constraints; it sets %0. %0 means the first register operand;
it is ret here.
This instruction might overwrite the %2 register (pte) which is needed
by the next instruction:
"(p7) st8 [%2]=r9;;"
Whether it really happens depends on how GCC decides what registers it
uses and how it optimizes the code.
The attached patch fixes the register operand constraints in
arch/ia64/kvm/vtlb.c.
The register constraints should be
: "=&r"(ret) : "r"(iha), "r"(pte):"memory");
The & means that GCC must not use any of the input registers to place
this output register in.
This is Debian bug#702639
(http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=702639).
The patch is applicable on Kernel 3.9-rc1, 3.2.35 and many other versions.
Signed-off-by: Stephan Schreiber <info@fs-driver.org> Cc: stable@vger.kernel.org Signed-off-by: Tony Luck <tony.luck@intel.com>
The list of output registers is
: "=r" (r8), "=r" (prev)
The constraint "=r" means that the GCC has to maintain that these vars
are in registers and contain valid info when the program flow leaves
the assembly block (output registers).
But "=r" also means that GCC can put them in registers that are used
as input registers. Input registers are uaddr, newval, oldval on the
example.
The second assembly instruction
" mov %0=r0 \n"
is the first one which writes to a register; it sets %0 to 0. %0 means
the first register operand; it is r8 here. (The r0 is read-only and
always 0 on the Itanium; it can be used if an immediate zero value is
needed.)
This instruction might overwrite one of the other registers which are
still needed.
Whether it really happens depends on how GCC decides what registers it
uses and how it optimizes the code.
The objdump utility can give us disassembly.
The futex_atomic_cmpxchg_inatomic() function is inline, so we have to
look for a module that uses the funtion. This is the
cmpxchg_futex_value_locked() function in
kernel/futex.c:
static int cmpxchg_futex_value_locked(u32 *curval, u32 __user *uaddr,
u32 uval, u32 newval)
{
int ret;
pagefault_disable();
ret = futex_atomic_cmpxchg_inatomic(curval, uaddr, uval, newval);
pagefault_enable();
return ret;
}
Now the disassembly. At first from the Kernel package 3.2.23 which has
been compiled with GCC 4.4, remeber this Kernel seemed to work:
objdump -d linux-3.2.23/debian/build/build_ia64_none_mckinley/kernel/futex.o
The lines
2b0: 0a 00 00 00 22 00 [MMI] mf;;
2b6: 80 00 00 00 42 00 mov r8=r0
2bc: 00 00 04 00 nop.i 0x0
2c0: 0b 00 20 40 2a 04 [MMI] mov.m ar.ccv=r8;;
2c6: 10 1a 85 22 20 00 cmpxchg4.acq r33=[r33],r35,ar.ccv
2cc: 00 00 04 00 nop.i 0x0;;
are the instructions of the assembly block.
The line
2b6: 80 00 00 00 42 00 mov r8=r0
sets the r8 register to 0 and after that
2c0: 0b 00 20 40 2a 04 [MMI] mov.m ar.ccv=r8;;
prepares the 'oldvalue' for the cmpxchg but it takes it from r8. This
is wrong.
What happened here is what I explained above: An input register is
overwritten which is still needed.
The register operand constraints in futex.h are wrong.
(The problem doesn't occur when the Kernel is compiled with GCC 4.6.)
The attached patch fixes the register operand constraints in futex.h.
The code after patching of it:
static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
return -EFAULT;
I also initialized the 'r8' var with the C programming language.
The _asm qualifier on the definition of the 'r8' var forces GCC to use
the r8 processor register for it.
I don't believe that we should use inline assembly for zeroing out a
local variable.
The constraint is
"+r" (r8)
what means that it is both an input register and an output register.
Note that the page fault handler will modify the r8 register which
will be the return value of the function.
The real fix is
"=&r" (prev)
The & means that GCC must not use any of the input registers to place
this output register in.
Patched the Kernel 3.2.23 and compiled it with GCC4.4:
Much better.
There is a
270: 05 40 00 00 00 e1 [MLX] mov r8=r0
which was generated by C code r8 = 0. Below
2b6: 00 10 81 54 08 00 mov.m ar.ccv=r34
what means that oldval is no longer overwritten.
This is Debian bug#702641
(http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=702641).
The patch is applicable on Kernel 3.9-rc1, 3.2.23 and many other versions.
Signed-off-by: Stephan Schreiber <info@fs-driver.org> Cc: stable@vger.kernel.org Signed-off-by: Tony Luck <tony.luck@intel.com>
Hanjun Guo [Fri, 8 Mar 2013 04:33:35 +0000 (12:33 +0800)]
Fix kexec oops when iosapic was removed
Iosapic hotplug was supported in IA64 code, but will lead to kexec oops
when iosapic was removed. here is the code logic:
iosapic_remove
iosapic_free
memset(&iosapic_lists[index], 0, sizeof(iosapic_lists[0]))
iosapic_lists[index].addr was set to 0;
and then kexec a new kernel
kexec_disable_iosapic
iosapic_write(rte->iosapic,..)
__iosapic_write(iosapic->addr, reg, val);
addr was set to 0 when iosapic_remove, and oops happened
Li, Zhen-Hua [Mon, 18 Mar 2013 02:45:43 +0000 (10:45 +0800)]
Add WB/UC check for early_ioremap
On ia64 system, the function early_ioremap returned an uncached memory
reference without checking whether this was consistent with existing
mappings. This causes efi error and the kernel failed during boot. Add a
check to test whether memory has EFI_MEMORY_WB set. Use the function
kern_mem_attribute() in early_iomap() function to provide appropriate
cacheable or uncacheable mapped address.
See the document Documentation/ia64/aliasing.txt for more details.
Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
In particular fsys_getppid always returns the ppid in the initial pid
namespace so it does not work for a process in a pid namespace.
Fix from Eric Biederman just removes the fast system call path.
While it is a little bit sad to see another one of these bite
the dust ... I can't imagine that getppid() is really on any
real applications critical path.
Daniel Vetter [Tue, 19 Mar 2013 22:48:39 +0000 (23:48 +0100)]
drm/i915: fixup pd vs pt confusion in gen6 ppgtt code
The index variable points at a page table, not a page directory or a
pde. Ben Widawsky fix this up correctly in his ppgtt cleanup, but I've
botched the job and copy&pasted the old confusion from the original
gen6 ppgtt code in
Linus Torvalds [Tue, 19 Mar 2013 22:17:40 +0000 (15:17 -0700)]
Merge tag 'for-linus-v3.9-rc4' of git://oss.sgi.com/xfs/xfs
Pull XFS fixes from Ben Myers:
- Fix for a potential infinite loop which was introduced in commit 4d559a3bcb73 ("xfs: limit speculative prealloc near ENOSPC
thresholds")
- Fix for the return type of xfs_iomap_eof_prealloc_initial_size from
commit a1e16c26660b ("xfs: limit speculative prealloc size on sparse
files")
- Fix for a failed buffer readahead causing subsequent callers to fail
incorrectly
* tag 'for-linus-v3.9-rc4' of git://oss.sgi.com/xfs/xfs:
xfs: ensure we capture IO errors correctly
xfs: fix xfs_iomap_eof_prealloc_initial_size type
xfs: fix potential infinite loop in xfs_iomap_prealloc_size()
Matthew Garrett [Tue, 19 Mar 2013 21:26:57 +0000 (17:26 -0400)]
PCI: Use ROM images from firmware only if no other ROM source available
Mantas Mikulėnas reported that his graphics hardware failed to
initialise after commit f9a37be0f02a ("x86: Use PCI setup data").
The aim of this commit was to ensure that ROM images were available on
some Apple systems that don't expose the GPU ROM via any other source.
In this case, UEFI appears to have provided a broken ROM image that we
were using even though there was a perfectly valid ROM available via
other sources. The simplest way to handle this seems to be to just
re-order pci_map_rom() and leave any firmare-supplied ROM to last.
Aristeu Rozanski [Fri, 15 Feb 2013 16:55:47 +0000 (11:55 -0500)]
devcg: propagate local changes down the hierarchy
This patch makes exception changes to propagate down in hierarchy respecting
when possible local exceptions.
New exceptions allowing additional access to devices won't be propagated, but
it'll be possible to add an exception to access all of part of the newly
allowed device(s).
New exceptions disallowing access to devices will be propagated down and the
local group's exceptions will be revalidated for the new situation.
Example:
A
/ \
B
group behavior exceptions
A allow "b 8:* rwm", "c 116:1 rw"
B deny "c 1:3 rwm", "c 116:2 rwm", "b 3:* rwm"
If a new exception is added to group A:
# echo "c 116:* r" > A/devices.deny
it'll propagate down and after revalidating B's local exceptions, the exception
"c 116:2 rwm" will be removed.
In case parent's exceptions change and local exceptions are not allowed anymore,
they'll be deleted.
v7:
- do not allow behavior change when the cgroup has children
- update documentation
v6: fixed issues pointed by Serge Hallyn
- only copy parent's exceptions while propagating behavior if the local
behavior is different
- while propagating exceptions, do not clear and copy parent's: it'd be against
the premise we don't propagate access to more devices
v5: fixed issues pointed by Serge Hallyn
- updated documentation
- not propagating when an exception is written to devices.allow
- when propagating a new behavior, clean the local exceptions list if they're
for a different behavior
v4: fixed issues pointed by Tejun Heo
- separated function to walk the tree and collect valid propagation targets
v3: fixed issues pointed by Tejun Heo
- update documentation
- move css_online/css_offline changes to a new patch
- use cgroup_for_each_descendant_pre() instead of own descendant walk
- move exception_copy rework to a separared patch
- move exception_clean rework to a separated patch
v2: fixed issues pointed by Tejun Heo
- instead of keeping the local settings that won't apply anymore, remove them
Aristeu Rozanski [Fri, 15 Feb 2013 16:55:46 +0000 (11:55 -0500)]
devcg: use css_online and css_offline
Allocate resources and change behavior only when online. This is needed in
order to determine if a node is suitable for hierarchy propagation or if it's
being removed.
Locking:
Both functions take devcgroup_mutex to make changes to device_cgroup structure.
Hierarchy propagation will also take devcgroup_mutex before walking the
tree while walking the tree itself is protected by rcu lock.
Aristeu Rozanski [Fri, 15 Feb 2013 16:55:45 +0000 (11:55 -0500)]
devcg: prepare may_access() for hierarchy support
Currently may_access() is only able to verify if an exception is valid for the
current cgroup, which has the same behavior. With hierarchy, it'll be also used
to verify if a cgroup local exception is valid towards its cgroup parent, which
might have different behavior.
v2:
- updated patch description
- rebased on top of a new patch to expand the may_access() logic to make it
more clear
- fixed argument description order in may_access()
Willem de Bruijn [Tue, 19 Mar 2013 10:18:11 +0000 (10:18 +0000)]
packet: packet fanout rollover during socket overload
Changes:
v3->v2: rebase (no other changes)
passes selftest
v2->v1: read f->num_members only once
fix bug: test rollover mode + flag
Minimize packet drop in a fanout group. If one socket is full,
roll over packets to another from the group. Maintain flow
affinity during normal load using an rxhash fanout policy, while
dispersing unexpected traffic storms that hit a single cpu, such
as spoofed-source DoS flows. Rollover breaks affinity for flows
arriving at saturated sockets during those conditions.
The patch adds a fanout policy ROLLOVER that rotates between sockets,
filling each socket before moving to the next. It also adds a fanout
flag ROLLOVER. If passed along with any other fanout policy, the
primary policy is applied until the chosen socket is full. Then,
rollover selects another socket, to delay packet drop until the
entire system is saturated.
Probing sockets is not free. Selecting the last used socket, as
rollover does, is a greedy approach that maximizes chance of
success, at the cost of extreme load imbalance. In practice, with
sufficiently long queues to absorb bursts, sockets are drained in
parallel and load balance looks uniform in `top`.
To avoid contention, scales counters with number of sockets and
accesses them lockfree. Values are bounds checked to ensure
correctness.
Tested using an application with 9 threads pinned to CPUs, one socket
per thread and sufficient busywork per packet operation to limits each
thread to handling 32 Kpps. When sent 500 Kpps single UDP stream
packets, a FANOUT_CPU setup processes 32 Kpps in total without this
patch, 270 Kpps with the patch. Tested with read() and with a packet
ring (V1).
Also, passes psock_fanout.c unit test added to selftests.
Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
projects / karo-tx-linux.git / log