Christophe Leroy 0e36b0d125 powerpc/mm: Only read faulting instruction when necessary in do_page_fault() ... Commit a7a9dcd882 ("powerpc: Avoid taking a data miss on every userspace instruction miss") has shown that limiting the read of faulting instruction to likely cases improves performance. This patch goes further into this direction by limiting the read of the faulting instruction to the only cases where it is likely needed. On an MPC885, with the same benchmark app as in the commit referred above, we see a reduction of about 3900 dTLB misses (approx 3%): Before the patch: Performance counter stats for './fault 500' (10 runs): 683033312 cpu-cycles ( +- 0.03% ) 134538 dTLB-load-misses ( +- 0.03% ) 46099 iTLB-load-misses ( +- 0.02% ) 19681 faults ( +- 0.02% ) 5.389747878 seconds time elapsed ( +- 0.06% ) With the patch: Performance counter stats for './fault 500' (10 runs): 682112862 cpu-cycles ( +- 0.03% ) 130619 dTLB-load-misses ( +- 0.03% ) 46073 iTLB-load-misses ( +- 0.05% ) 19681 faults ( +- 0.01% ) 5.381342641 seconds time elapsed ( +- 0.07% ) The proper work of the huge stack expansion was tested with the following app: int main(int argc, char **argv) { char buf[1024 * 1025]; sprintf(buf, "Hello world !\n"); printf(buf); exit(0); } Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Add include of pagemap.h to fix build errors] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>		2018-05-25 00:08:25 +10:00
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boot	powerpc/fsl/dts: fix the i2c-mux compatible for t104xqds	2018-05-21 14:48:01 +10:00
configs	powerpc/config: powernv_defconfig updates	2018-05-10 23:25:07 +10:00
crypto
include	powerpc/mm: Use instruction symbolic names in store_updates_sp()	2018-05-25 00:08:24 +10:00
kernel	powerpc/ptrace: Fix setting 512B aligned breakpoints with PTRACE_SET_DEBUGREG	2018-05-21 14:48:01 +10:00
kvm	Merge branch 'topic/ppc-kvm' into next	2018-05-15 22:28:19 +10:00
lib	powerpc/lib: Fix "integer constant is too large" build failure	2018-05-18 16:04:02 +10:00
math-emu
mm	powerpc/mm: Only read faulting instruction when necessary in do_page_fault()	2018-05-25 00:08:25 +10:00
net
oprofile
perf	powerpc/perf: Fix memory allocation for core-imc based on num_possible_cpus()	2018-05-18 21:57:49 +10:00
platforms	powernv: opal-sensor: Add support to read 64bit sensor values	2018-05-21 14:48:02 +10:00
purgatory
sysdev	powerpc/xive: prepare all hcalls to support long busy delays	2018-05-10 23:25:10 +10:00
tools
xmon
Kconfig	powerpc/livepatch: Implement reliable stack tracing for the consistency model	2018-05-10 23:25:12 +10:00
Kconfig.debug
Makefile
Makefile.postlink