linux-stable/arch/sparc/mm
David S. Miller a74ad5e660 sparc64: Handle extremely large kernel TLB range flushes more gracefully.
When the vmalloc area gets fragmented, and because the firmware
mapping area sits between where modules live and the vmalloc area, we
can sometimes receive requests for enormous kernel TLB range flushes.

When this happens the cpu just spins flushing billions of pages and
this triggers the NMI watchdog and other problems.

We took care of this on the TSB side by doing a linear scan of the
table once we pass a certain threshold.

Do something similar for the TLB flush, however we are limited by
the TLB flush facilities provided by the different chip variants.

First of all we use an (mostly arbitrary) cut-off of 256K which is
about 32 pages.  This can be tuned in the future.

The huge range code path for each chip works as follows:

1) On spitfire we flush all non-locked TLB entries using diagnostic
   acceses.

2) On cheetah we use the "flush all" TLB flush.

3) On sun4v/hypervisor we do a TLB context flush on context 0, which
   unlike previous chips does not remove "permanent" or locked
   entries.

We could probably do something better on spitfire, such as limiting
the flush to kernel TLB entries or even doing range comparisons.
However that probably isn't worth it since those chips are old and
the TLB only had 64 entries.

Reported-by: James Clarke <jrtc27@jrtc27.com>
Tested-by: James Clarke <jrtc27@jrtc27.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-27 09:11:05 -07:00
..
extable.c sparc: Add module.h to files previously implicitly using it. 2011-10-31 19:30:54 -04:00
fault_32.c mm: do not pass mm_struct into handle_mm_fault 2016-07-26 16:19:19 -07:00
fault_64.c sparc: migrate exception table users off module.h and onto extable.h 2016-10-06 01:42:30 -04:00
gup.c mm: replace get_user_pages_unlocked() write/force parameters with gup_flags 2016-10-18 14:13:37 -07:00
highmem.c sched/preempt, mm/kmap: Explicitly disable/enable preemption in kmap_atomic_* 2015-05-19 08:39:14 +02:00
hugetlbpage.c sparc64: Trim page tables for 8M hugepages 2016-07-29 10:49:16 -07:00
hypersparc.S [PATCH] sparc32: vm_area_struct access for old Sun SPARCs. 2013-07-10 13:56:10 -07:00
init_32.c sparc32: fix sparse warning in devices.c 2014-04-29 01:12:26 -04:00
init_64.c sparc: migrate exception table users off module.h and onto extable.h 2016-10-06 01:42:30 -04:00
init_64.h sparc64: Use kernel page tables for vmemmap. 2014-10-05 16:53:39 -07:00
io-unit.c sparc32: fix build with STRICT_MM_TYPECHECKS 2016-05-20 17:55:42 -07:00
iommu.c sparc32: fix sparse warning in iommu.c 2014-05-18 19:01:26 -07:00
leon_mm.c sparc32: fix sparse "Should it be static?" in mm/ 2014-04-29 01:12:25 -04:00
Makefile sparc32: introduce run-time patching of srmmu access functions 2012-05-27 23:52:49 -07:00
mm_32.h sparc32: fix sparse "Should it be static?" in mm/ 2014-04-29 01:12:25 -04:00
srmmu.c sparc32: drop superfluous cast in calls to __nocache_pa() 2016-05-20 17:55:42 -07:00
srmmu_access.S sparc32: introduce run-time patching of srmmu access functions 2012-05-27 23:52:49 -07:00
swift.S [PATCH] sparc32: vm_area_struct access for old Sun SPARCs. 2013-07-10 13:56:10 -07:00
tlb.c sparc64 mm: Fix more TSB sizing issues 2016-09-28 08:24:02 -07:00
tsb.c sparc64: Handle extremely large kernel TSB range flushes sanely. 2016-10-25 19:43:17 -07:00
tsunami.S [PATCH] sparc32: vm_area_struct access for old Sun SPARCs. 2013-07-10 13:56:10 -07:00
ultra.S sparc64: Handle extremely large kernel TLB range flushes more gracefully. 2016-10-27 09:11:05 -07:00
viking.S [PATCH] sparc32: vm_area_struct access for old Sun SPARCs. 2013-07-10 13:56:10 -07:00