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author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-15 05:35:53 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-15 05:35:53 +0300 |
commit | edd7ab76847442e299af64a761febd180d71f98d (patch) | |
tree | 91c3ee6ca27074c655bc1aaf04358f4e41df54d4 /lib/Kconfig.debug | |
parent | adb35e8dc98ba9bda99ff79ac6a05b8fcde2a762 (diff) | |
parent | 68061c02bb295da4955f0d309b9459f0a7ba83dd (diff) | |
download | linux-edd7ab76847442e299af64a761febd180d71f98d.tar.xz |
Merge tag 'core-mm-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull kmap updates from Thomas Gleixner:
"The new preemtible kmap_local() implementation:
- Consolidate all kmap_atomic() internals into a generic
implementation which builds the base for the kmap_local() API and
make the kmap_atomic() interface wrappers which handle the
disabling/enabling of preemption and pagefaults.
- Switch the storage from per-CPU to per task and provide scheduler
support for clearing mapping when scheduling out and restoring them
when scheduling back in.
- Merge the migrate_disable/enable() code, which is also part of the
scheduler pull request. This was required to make the kmap_local()
interface available which does not disable preemption when a
mapping is established. It has to disable migration instead to
guarantee that the virtual address of the mapped slot is the same
across preemption.
- Provide better debug facilities: guard pages and enforced
utilization of the mapping mechanics on 64bit systems when the
architecture allows it.
- Provide the new kmap_local() API which can now be used to cleanup
the kmap_atomic() usage sites all over the place. Most of the usage
sites do not require the implicit disabling of preemption and
pagefaults so the penalty on 64bit and 32bit non-highmem systems is
removed and quite some of the code can be simplified. A wholesale
conversion is not possible because some usage depends on the
implicit side effects and some need to be cleaned up because they
work around these side effects.
The migrate disable side effect is only effective on highmem
systems and when enforced debugging is enabled. On 64bit and 32bit
non-highmem systems the overhead is completely avoided"
* tag 'core-mm-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits)
ARM: highmem: Fix cache_is_vivt() reference
x86/crashdump/32: Simplify copy_oldmem_page()
io-mapping: Provide iomap_local variant
mm/highmem: Provide kmap_local*
sched: highmem: Store local kmaps in task struct
x86: Support kmap_local() forced debugging
mm/highmem: Provide CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP
mm/highmem: Provide and use CONFIG_DEBUG_KMAP_LOCAL
microblaze/mm/highmem: Add dropped #ifdef back
xtensa/mm/highmem: Make generic kmap_atomic() work correctly
mm/highmem: Take kmap_high_get() properly into account
highmem: High implementation details and document API
Documentation/io-mapping: Remove outdated blurb
io-mapping: Cleanup atomic iomap
mm/highmem: Remove the old kmap_atomic cruft
highmem: Get rid of kmap_types.h
xtensa/mm/highmem: Switch to generic kmap atomic
sparc/mm/highmem: Switch to generic kmap atomic
powerpc/mm/highmem: Switch to generic kmap atomic
nds32/mm/highmem: Switch to generic kmap atomic
...
Diffstat (limited to 'lib/Kconfig.debug')
-rw-r--r-- | lib/Kconfig.debug | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index c789b39ed527..e952f892f047 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -849,9 +849,31 @@ config DEBUG_PER_CPU_MAPS Say N if unsure. +config DEBUG_KMAP_LOCAL + bool "Debug kmap_local temporary mappings" + depends on DEBUG_KERNEL && KMAP_LOCAL + help + This option enables additional error checking for the kmap_local + infrastructure. Disable for production use. + +config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP + bool + +config DEBUG_KMAP_LOCAL_FORCE_MAP + bool "Enforce kmap_local temporary mappings" + depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP + select KMAP_LOCAL + select DEBUG_KMAP_LOCAL + help + This option enforces temporary mappings through the kmap_local + mechanism for non-highmem pages and on non-highmem systems. + Disable this for production systems! + config DEBUG_HIGHMEM bool "Highmem debugging" depends on DEBUG_KERNEL && HIGHMEM + select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP + select DEBUG_KMAP_LOCAL help This option enables additional error checking for high memory systems. Disable for production systems. |