The patch titled
Subject: arch: remove GENERIC_FIND_FIRST_BIT entirely
has been added to the -mm tree. Its filename is
arch-remove-generic_find_first_bit-entirely.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/arch-remove-generic_find_first_bit-entirely.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/arch-remove-generic_find_first_bit-entirely.patch
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------------------------------------------------------
From: Yury Norov <yury.norov@xxxxxxxxx>
Subject: arch: remove GENERIC_FIND_FIRST_BIT entirely
In 5.12 cycle we enabled GENERIC_FIND_FIRST_BIT config option for ARM64
and MIPS. It increased performance and shrunk .text size; and so far I
didn't receive any negative feedback on the change.
https://lore.kernel.org/linux-arch/20210225135700.1381396-1-yury.norov@xxxxxxxxx/
Now I think it's a good time to switch all architectures to use
find_{first,last}_bit() unconditionally, and so remove corresponding
config option.
The patch does't introduce functioal changes for arc, arm, arm64, mips,
m68k, s390 and x86, for other architectures I expect improvement both in
performance and .text size.
Link: https://lkml.kernel.org/r/20210814211713.180533-5-yury.norov@xxxxxxxxx
Signed-off-by: Yury Norov <yury.norov@xxxxxxxxx>
Tested-by: Alexander Lobakin <alobakin@xxxxx> (mips)
Reviewed-by: Alexander Lobakin <alobakin@xxxxx> (mips)
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Acked-by: Will Deacon <will@xxxxxxxxxx>
Tested-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Cc: Alexey Klimov <aklimov@xxxxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: kernel test robot <lkp@xxxxxxxxx>
Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arc/Kconfig | 1 -
arch/arm64/Kconfig | 1 -
arch/mips/Kconfig | 1 -
arch/s390/Kconfig | 1 -
arch/x86/Kconfig | 1 -
arch/x86/um/Kconfig | 1 -
include/linux/find.h | 13 -------------
lib/Kconfig | 3 ---
8 files changed, 22 deletions(-)
--- a/arch/arc/Kconfig~arch-remove-generic_find_first_bit-entirely
+++ a/arch/arc/Kconfig
@@ -20,7 +20,6 @@ config ARC
select COMMON_CLK
select DMA_DIRECT_REMAP
select GENERIC_ATOMIC64 if !ISA_ARCV2 || !(ARC_HAS_LL64 && ARC_HAS_LLSC)
- select GENERIC_FIND_FIRST_BIT
# for now, we don't need GENERIC_IRQ_PROBE, CONFIG_GENERIC_IRQ_CHIP
select GENERIC_IRQ_SHOW
select GENERIC_PCI_IOMAP
--- a/arch/arm64/Kconfig~arch-remove-generic_find_first_bit-entirely
+++ a/arch/arm64/Kconfig
@@ -119,7 +119,6 @@ config ARM64
select GENERIC_CPU_AUTOPROBE
select GENERIC_CPU_VULNERABILITIES
select GENERIC_EARLY_IOREMAP
- select GENERIC_FIND_FIRST_BIT
select GENERIC_IDLE_POLL_SETUP
select GENERIC_IRQ_IPI
select GENERIC_IRQ_PROBE
--- a/arch/mips/Kconfig~arch-remove-generic_find_first_bit-entirely
+++ a/arch/mips/Kconfig
@@ -30,7 +30,6 @@ config MIPS
select GENERIC_ATOMIC64 if !64BIT
select GENERIC_CMOS_UPDATE
select GENERIC_CPU_AUTOPROBE
- select GENERIC_FIND_FIRST_BIT
select GENERIC_GETTIMEOFDAY
select GENERIC_IOMAP
select GENERIC_IRQ_PROBE
--- a/arch/s390/Kconfig~arch-remove-generic_find_first_bit-entirely
+++ a/arch/s390/Kconfig
@@ -126,7 +126,6 @@ config S390
select GENERIC_CPU_AUTOPROBE
select GENERIC_CPU_VULNERABILITIES
select GENERIC_ENTRY
- select GENERIC_FIND_FIRST_BIT
select GENERIC_GETTIMEOFDAY
select GENERIC_PTDUMP
select GENERIC_SMP_IDLE_THREAD
--- a/arch/x86/Kconfig~arch-remove-generic_find_first_bit-entirely
+++ a/arch/x86/Kconfig
@@ -133,7 +133,6 @@ config X86
select GENERIC_CPU_VULNERABILITIES
select GENERIC_EARLY_IOREMAP
select GENERIC_ENTRY
- select GENERIC_FIND_FIRST_BIT
select GENERIC_IOMAP
select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
--- a/arch/x86/um/Kconfig~arch-remove-generic_find_first_bit-entirely
+++ a/arch/x86/um/Kconfig
@@ -8,7 +8,6 @@ endmenu
config UML_X86
def_bool y
- select GENERIC_FIND_FIRST_BIT
config 64BIT
bool "64-bit kernel" if "$(SUBARCH)" = "x86"
--- a/include/linux/find.h~arch-remove-generic_find_first_bit-entirely
+++ a/include/linux/find.h
@@ -101,8 +101,6 @@ unsigned long find_next_zero_bit(const u
}
#endif
-#ifdef CONFIG_GENERIC_FIND_FIRST_BIT
-
#ifndef find_first_bit
/**
* find_first_bit - find the first set bit in a memory region
@@ -147,17 +145,6 @@ unsigned long find_first_zero_bit(const
}
#endif
-#else /* CONFIG_GENERIC_FIND_FIRST_BIT */
-
-#ifndef find_first_bit
-#define find_first_bit(addr, size) find_next_bit((addr), (size), 0)
-#endif
-#ifndef find_first_zero_bit
-#define find_first_zero_bit(addr, size) find_next_zero_bit((addr), (size), 0)
-#endif
-
-#endif /* CONFIG_GENERIC_FIND_FIRST_BIT */
-
#ifndef find_last_bit
/**
* find_last_bit - find the last set bit in a memory region
--- a/lib/Kconfig~arch-remove-generic_find_first_bit-entirely
+++ a/lib/Kconfig
@@ -59,9 +59,6 @@ config GENERIC_STRNLEN_USER
config GENERIC_NET_UTILS
bool
-config GENERIC_FIND_FIRST_BIT
- bool
-
source "lib/math/Kconfig"
config NO_GENERIC_PCI_IOPORT_MAP
_
Patches currently in -mm which might be from yury.norov@xxxxxxxxx are
bitops-protect-find_first_zero_bit-properly.patch
bitops-move-find_bit__le-functions-from-leh-to-findh.patch
include-move-findh-from-asm_generic-to-linux.patch
arch-remove-generic_find_first_bit-entirely.patch
lib-add-find_first_and_bit.patch
cpumask-use-find_first_and_bit.patch
all-replace-find_next_zero_bit-with-find_first_zero_bit-where-appropriate.patch
tools-sync-tools-bitmap-with-mother-linux.patch
cpumask-replace-cpumask_next_-with-cpumask_first_-where-appropriate.patch
include-linux-move-for_each_bit-macros-from-bitopsh-to-findh.patch
find-micro-optimize-for_each_setclear_bit.patch
replace-for_each__bit_from-with-for_each__bit-where-appropriate.patch
mm-percpu-micro-optimize-pcpu_is_populated.patch
bitmap-unify-find_bit-operations.patch
lib-bitmap-add-performance-test-for-bitmap_print_to_pagebuf.patch
vsprintf-rework-bitmap_list_string.patch
