linux_dsm_epyc7002/arch/sparc
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
..
boot sparc: Add "install" target 2014-08-04 20:45:59 -07:00
configs sparc/defconfigs: Remove CONFIG_IPV6_PRIVACY 2016-04-21 16:43:44 -04:00
crypto crypto: sparc - initialize blkcipher.ivsize 2015-10-08 21:36:48 +08:00
include sparc64: Delete now unused user copy fixup functions. 2016-10-24 21:26:04 -07:00
kernel sparc: Handle negative offsets in arch_jump_label_transform 2016-10-25 19:11:17 -07:00
lib sparc64: Delete now unused user copy fixup functions. 2016-10-24 21:26:04 -07:00
math-emu arch/sparc/math-emu/math_32.c: drop stray break operator 2014-08-04 20:29:06 -07:00
mm sparc64: Handle extremely large kernel TLB range flushes more gracefully. 2016-10-27 09:11:05 -07:00
net sparc: Fix misspellings in comments. 2016-03-20 21:28:58 -07:00
oprofile sparc: using HZ needs an include of linux/param.h 2009-10-05 00:46:08 -07:00
power Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc 2014-10-11 20:36:34 -04:00
prom sparc: fixing ident and beautifying code 2016-10-06 01:46:40 -04:00
Kbuild sparc64: Add SHA1 driver making use of the 'sha1' instruction. 2012-08-20 15:08:49 -07:00
Kconfig atomic64: no need for CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE 2016-10-07 18:46:30 -07:00
Kconfig.debug lib: consolidate DEBUG_STACK_USAGE option 2011-05-25 08:39:54 -07:00
Makefile sparc32: Add -Wa,-Av8 to KBUILD_CFLAGS. 2016-03-01 00:24:04 -05:00