The main purpose of this patchset is to dramatically reduce the time
spent in DTLB miss handler. This is achieved by:
1/ Mapping RAM with 8M pages
2/ Mapping IMMR with a fixed 512K page
On a live running system (VoIP gateway for Air Trafic Control), over
a 10 minutes period (with 277s idle), we get 87 millions DTLB misses
and approximatly 35 secondes are spent in DTLB handler.
This represents 5.8% of the overall time and even 10.8% of the
non-idle time.
Among those 87 millions DTLB misses, 15% are on user addresses and
85% are on kernel addresses. And within the kernel addresses, 93%
are on addresses from the linear address space and only 7% are on
addresses from the virtual address space.
Once the full patchset applied, the number of DTLB misses during the
period is reduced to 11.8 millions for a duration of 5.8s, which
represents 2% of the non-idle time.
This patch also includes other miscellaneous improvements:
1/ Handling of CPU6 ERRATA directly in mtspr() C macro to reduce code
specific to PPC8xx
2/ Rewrite of a few non critical ASM functions in C
3/ Removal of some unused items
See related patches for details
Main changes in v3:
* Using fixmap instead of fix address for mapping IMMR
Change in v4:
* Fix of a wrong #if notified by kbuild robot in 07/23
Change in v5:
* Removed use of pmd_val() as L-value
* Adapted to match the new include files layout in Linux 4.5
Christophe Leroy (23):
powerpc/8xx: Save r3 all the time in DTLB miss handler
powerpc/8xx: Map linear kernel RAM with 8M pages
powerpc: Update documentation for noltlbs kernel parameter
powerpc/8xx: move setup_initial_memory_limit() into 8xx_mmu.c
powerpc32: Fix pte_offset_kernel() to return NULL for bad pages
powerpc32: refactor x_mapped_by_bats() and x_mapped_by_tlbcam()
together
powerpc/8xx: Fix vaddr for IMMR early remap
powerpc/8xx: Map IMMR area with 512k page at a fixed address
powerpc/8xx: CONFIG_PIN_TLB unneeded for CONFIG_PPC_EARLY_DEBUG_CPM
powerpc/8xx: map more RAM at startup when needed
powerpc32: Remove useless/wrong MMU:setio progress message
powerpc32: remove ioremap_base
powerpc/8xx: Add missing SPRN defines into reg_8xx.h
powerpc/8xx: Handle CPU6 ERRATA directly in mtspr() macro
powerpc/8xx: remove special handling of CPU6 errata in set_dec()
powerpc/8xx: rewrite set_context() in C
powerpc/8xx: rewrite flush_instruction_cache() in C
powerpc: add inline functions for cache related instructions
powerpc32: Remove clear_pages() and define clear_page() inline
powerpc32: move xxxxx_dcache_range() functions inline
powerpc: Simplify test in __dma_sync()
powerpc32: small optimisation in flush_icache_range()
powerpc32: Remove one insn in mulhdu
Documentation/kernel-parameters.txt | 2 +-
arch/powerpc/Kconfig.debug | 1 -
arch/powerpc/include/asm/cache.h | 19 +++
arch/powerpc/include/asm/cacheflush.h | 52 ++++++-
arch/powerpc/include/asm/fixmap.h | 14 ++
arch/powerpc/include/asm/mmu-8xx.h | 4 +-
arch/powerpc/include/asm/nohash/32/pgtable.h | 5 +-
arch/powerpc/include/asm/page_32.h | 17 ++-
arch/powerpc/include/asm/reg.h | 2 +
arch/powerpc/include/asm/reg_8xx.h | 93 ++++++++++++
arch/powerpc/include/asm/time.h | 6 +-
arch/powerpc/kernel/asm-offsets.c | 8 ++
arch/powerpc/kernel/head_8xx.S | 207 +++++++++++++++++----------
arch/powerpc/kernel/misc_32.S | 107 ++------------
arch/powerpc/kernel/ppc_ksyms.c | 2 +
arch/powerpc/kernel/ppc_ksyms_32.c | 1 -
arch/powerpc/mm/8xx_mmu.c | 190 ++++++++++++++++++++++++
arch/powerpc/mm/Makefile | 1 +
arch/powerpc/mm/dma-noncoherent.c | 2 +-
arch/powerpc/mm/fsl_booke_mmu.c | 4 +-
arch/powerpc/mm/init_32.c | 23 ---
arch/powerpc/mm/mmu_decl.h | 34 +++--
arch/powerpc/mm/pgtable_32.c | 47 +-----
arch/powerpc/mm/ppc_mmu_32.c | 4 +-
arch/powerpc/platforms/embedded6xx/mpc10x.h | 10 --
arch/powerpc/sysdev/cpm_common.c | 15 +-
26 files changed, 583 insertions(+), 287 deletions(-)
create mode 100644 arch/powerpc/mm/8xx_mmu.c
--
2.1.0
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