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Subject[PATCH v3 0/5] elide extraneous generated code for folded p4d/pud/pmd
Date
Hi,

This series came out of seemingly benign excursion into understanding/removing
__ARCH_USE_5LEVEL_HACK from ARC port showing some extraneous code being
generated despite folded p4d/pud/pmd

| bloat-o-meter2 vmlinux-[AB]*
| add/remove: 0/0 grow/shrink: 3/0 up/down: 130/0 (130)
| function old new delta
| free_pgd_range 548 660 +112
| p4d_clear_bad 2 20 +18

The patches here address that

| bloat-o-meter2 vmlinux-[BF]*
| add/remove: 0/2 grow/shrink: 0/1 up/down: 0/-386 (-386)
| function old new delta
| pud_clear_bad 20 - -20
| p4d_clear_bad 20 - -20
| free_pgd_range 660 314 -346

The code savings are not a whole lot, but still worthwhile IMHO.

Please review, test and apply. It seems to survive my usual battery of
multibench, hakcbench etc.

Thx,
-Vineet

---
Changes since v2 [3]
- No code changes: Fixed the silly typos and collected ACKs

Changes since v1 [1]
- Per Linus Sugestion remvoed the extra ifdey'ery (hence not
accumulating Kirill's ACks)
- Added the RFC patch for pmd_free_tlb() after discussions [2]
- Also throwing in the ARC patch which started this all (so we get the
full context of patchset) - I'm ok if this goes via mm tree, should
be non contentious and can drop this too if Andrew thinks otherwise

[1] http://lists.infradead.org/pipermail/linux-snps-arc/2019-October/006263.html
[2] http://lists.infradead.org/pipermail/linux-snps-arc/2019-October/006277.html
[3] http://lists.infradead.org/pipermail/linux-snps-arc/2019-October/006307.html
---

Vineet Gupta (5):
ARC: mm: remove __ARCH_USE_5LEVEL_HACK
asm-generic/tlb: stub out pud_free_tlb() if nopud ...
asm-generic/tlb: stub out p4d_free_tlb() if nop4d ...
asm-generic/tlb: stub out pmd_free_tlb() if nopmd
asm-generic/mm: stub out p{4,u}d_clear_bad() if
__PAGETABLE_P{4,u}D_FOLDED

arch/arc/include/asm/pgtable.h | 1 -
arch/arc/mm/fault.c | 10 ++++++++--
arch/arc/mm/highmem.c | 4 +++-
include/asm-generic/4level-fixup.h | 1 -
include/asm-generic/5level-fixup.h | 1 -
include/asm-generic/pgtable-nop4d.h | 2 +-
include/asm-generic/pgtable-nopmd.h | 2 +-
include/asm-generic/pgtable-nopud.h | 2 +-
include/asm-generic/pgtable.h | 11 +++++++++++
include/asm-generic/tlb.h | 4 ----
mm/pgtable-generic.c | 9 +++++++++
11 files changed, 34 insertions(+), 13 deletions(-)

--
2.20.1

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