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  1. 25 9月, 2014 2 次提交
  3. 13 8月, 2014 4 次提交
    • N
      powerpc: reorder per-cpu NUMA information's initialization · 2fabf084
      由 Nishanth Aravamudan 提交于 
      There is an issue currently where NUMA information is used on powerpc
(and possibly ia64) before it has been read from the device-tree, which
leads to large slab consumption with CONFIG_SLUB and memoryless nodes.

NUMA powerpc non-boot CPU's cpu_to_node/cpu_to_mem is only accurate
after start_secondary(), similar to ia64, which is invoked via
smp_init().

Commit 6ee0578b ("workqueue: mark init_workqueues() as
early_initcall()") made init_workqueues() be invoked via
do_pre_smp_initcalls(), which is obviously before the secondary
processors are online.

Additionally, the following commits changed init_workqueues() to use
cpu_to_node to determine the node to use for kthread_create_on_node:

bce90380 ("workqueue: add wq_numa_tbl_len and
wq_numa_possible_cpumask[]")
f3f90ad4 ("workqueue: determine NUMA node of workers accourding to
the allowed cpumask")

Therefore, when init_workqueues() runs, it sees all CPUs as being on
Node 0. On LPARs or KVM guests where Node 0 is memoryless, this leads to
a high number of slab deactivations
(http://www.spinics.net/lists/linux-mm/msg67489.html).

Fix this by initializing the powerpc-specific CPU<->node/local memory
node mapping as early as possible, which on powerpc is
do_init_bootmem(). Currently that function initializes the mapping for
the boot CPU, but we extend it to setup the mapping for all possible
CPUs. Then, in smp_prepare_cpus(), we can correspondingly set the
per-cpu values for all possible CPUs. That ensures that before the
early_initcalls run (and really as early as possible), the per-cpu NUMA
mapping is accurate.

While testing memoryless nodes on PowerKVM guests with a fix to the
workqueue logic to use cpu_to_mem() instead of cpu_to_node(), with a
guest topology of:

available: 2 nodes (0-1)
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
node 0 size: 0 MB
node 0 free: 0 MB
node 1 cpus: 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
node 1 size: 16336 MB
node 1 free: 15329 MB
node distances:
node   0   1
  0:  10  40
  1:  40  10

the slab consumption decreases from

Slab:             932416 kB
SUnreclaim:       902336 kB

to

Slab:             395264 kB
SUnreclaim:       359424 kB

And we a corresponding increase in the slab efficiency from

slab                                   mem     objs    slabs
                                      used   active   active
------------------------------------------------------------
kmalloc-16384                       337 MB   11.28%  100.00%
task_struct                         288 MB    9.93%  100.00%

to

slab                                   mem     objs    slabs
                                      used   active   active
------------------------------------------------------------
kmalloc-16384                        37 MB  100.00%  100.00%
task_struct                          31 MB  100.00%  100.00%

Powerpc didn't support memoryless nodes until recently (64bb80d8
"powerpc/numa: Enable CONFIG_HAVE_MEMORYLESS_NODES" and 8c272261
"powerpc/numa: Enable USE_PERCPU_NUMA_NODE_ID"). Those commits also
helped improve memory consumption with these kind of environments.
Signed-off-by: NNishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      2fabf084
    • A
      powerpc/ppc476: Disable BTAC · 97b3be1e
      由 Alistair Popple 提交于 
      This patch disables the branch target address CAM which under specific
circumstances may cause the processor to skip execution of 1-4
instructions. This fixes IBM Erratum #47.
Signed-off-by: NAlistair Popple <alistair@popple.id.au>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      97b3be1e
    • G
      powerpc/powernv: Fix IOMMU group lost · 763fe0ad
      由 Gavin Shan 提交于 
      When we take full hotplug to recover from EEH errors, PCI buses
could be involved. For the case, the child devices of involved
PCI buses can't be attached to IOMMU group properly, which is
caused by commit 3f28c5af ("powerpc/powernv: Reduce multi-hit of
iommu_add_device()").

When adding the PCI devices of the newly created PCI buses to
the system, the IOMMU group is expected to be added in (C).
(A) fails to bind the IOMMU group because bus->is_added is
false. (B) fails because the device doesn't have binding IOMMU
table yet. bus->is_added is set to true at end of (C) and
pdev->is_added is set to true at (D).

   pcibios_add_pci_devices()
      pci_scan_bridge()
         pci_scan_child_bus()
            pci_scan_slot()
               pci_scan_single_device()
                  pci_scan_device()
                  pci_device_add()
                     pcibios_add_device()           A: Ignore
                     device_add()                   B: Ignore
                  pcibios_fixup_bus()
                     pcibios_setup_bus_devices()
                        pcibios_setup_device()      C: Hit
      pcibios_finish_adding_to_bus()
         pci_bus_add_devices()
            pci_bus_add_device()                    D: Add device

If the parent PCI bus isn't involved in hotplug, the IOMMU
group is expected to be bound in (B). (A) should fail as the
sysfs entries aren't populated.

The patch fixes the issue by reverting commit 3f28c5af and remove
WARN_ON() in iommu_add_device() to allow calling the function
even the specified device already has associated IOMMU group.

Cc: <stable@vger.kernel.org>  # 3.16+
Reported-by: NThadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      763fe0ad
    • G
      powerpc: Fix "attempt to move .org backwards" error · 11d54904
      由 Guenter Roeck 提交于 
      Once again, we see

arch/powerpc/kernel/exceptions-64s.S: Assembler messages:
arch/powerpc/kernel/exceptions-64s.S:865: Error: attempt to move .org backwards
arch/powerpc/kernel/exceptions-64s.S:866: Error: attempt to move .org backwards
arch/powerpc/kernel/exceptions-64s.S:890: Error: attempt to move .org backwards

when compiling ppc:allmodconfig.

This time the problem has been caused by to commit 0869b6fd
("powerpc/book3s: Add basic infrastructure to handle HMI in Linux"),
which adds functions hmi_exception_early and hmi_exception_after_realmode
into a critical (size-limited) code area, even though that does not appear
to be necessary.

Move those functions to a non-critical area of the file.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      11d54904
  5. 09 8月, 2014 2 次提交
  7. 07 8月, 2014 1 次提交
  9. 06 8月, 2014 2 次提交
  11. 05 8月, 2014 16 次提交
  13. 30 7月, 2014 1 次提交
    • A
      powerpc/e6500: Add support for hardware threads · e16c8765
      由 Andy Fleming 提交于 
      The general idea is that each core will release all of its
threads into the secondary thread startup code, which will
eventually wait in the secondary core holding area, for the
appropriate bit in the PACA to be set. The kick_cpu function
pointer will set that bit in the PACA, and thus "release"
the core/thread to boot. We also need to do a few things that
U-Boot normally does for CPUs (like enable branch prediction).
Signed-off-by: NAndy Fleming <afleming@freescale.com>
[scottwood@freescale.com: various changes, including only enabling
 threads if Linux wants to kick them]
Signed-off-by: NScott Wood <scottwood@freescale.com>
      e16c8765
  15. 28 7月, 2014 12 次提交