On Tue, Nov 03 2020 at 09:48, Linus Torvalds wrote:
> I have no complaints about the patch, but it strikes me that if people
> want to actually have much better debug coverage, this is where it
> should be (I like the "every other address" thing too, don't get me
> wrong).
>
> In particular, instea
On Tue, Nov 3, 2020 at 2:33 AM Thomas Gleixner wrote:
>
> +static inline void *kmap(struct page *page)
> +{
> + void *addr;
> +
> + might_sleep();
> + if (!PageHighMem(page))
> + addr = page_address(page);
> + else
> + addr = kmap_high(page);
> +
Instead of storing the map per CPU provide and use per task storage. That
prepares for local kmaps which are preemptible.
The context switch code is preparatory and not yet in use because
kmap_atomic() runs with preemption disabled. Will be made usable in the
next step.
The context switch logic i
On Tue, Nov 03 2020 at 10:27, Thomas Gleixner wrote:
> +struct kmap_ctrl {
> +#ifdef CONFIG_KMAP_LOCAL
> + int idx;
> + pte_t pteval[KM_TYPE_NR];
I'm a moron. Fixed it on the test machine ...
___
On Tue, Nov 3, 2020 at 10:27 AM Thomas Gleixner wrote:
>
> kmap_types.h is a misnomer because the old atomic MAP based array does not
> exist anymore and the whole indirection of architectures including
> kmap_types.h is inconinstent and does not allow to provide guard page
> debugging for this mi
For whatever reasons SH has highmem bits all over the place but does
not enable it via Kconfig. Remove the bitrot.
Signed-off-by: Thomas Gleixner
---
arch/sh/include/asm/fixmap.h |8
arch/sh/include/asm/kmap_types.h | 15 ---
arch/sh/mm/init.c|8
Historical leftovers from the time where kmap() had fixed slots.
Signed-off-by: Thomas Gleixner
Cc: Alexander Viro
Cc: Benjamin LaHaise
Cc: linux-fsde...@vger.kernel.org
Cc: linux-...@kvack.org
Cc: Chris Mason
Cc: Josef Bacik
Cc: David Sterba
Cc: linux-bt...@vger.kernel.org
---
fs/aio.c
Neither fbmem_peek() nor fbmem_poke() require to disable pagefaults and
preemption as a side effect of io_mapping_map_atomic_wc().
Use io_mapping_map_local_wc() instead.
Signed-off-by: Thomas Gleixner
Cc: Ben Skeggs
Cc: David Airlie
Cc: Daniel Vetter
Cc: dri-de...@lists.freedesktop.org
Cc: no
Following up to the discussion in:
https://lore.kernel.org/r/20200914204209.256266...@linutronix.de
and the second version of this:
https://lore.kernel.org/r/20201029221806.189523...@linutronix.de
this series provides a preemptible variant of kmap_atomic & related
interfaces.
This is achie
On Tue, Nov 03, 2020 at 10:27:15AM +0100, Thomas Gleixner wrote:
> Historical leftovers from the time where kmap() had fixed slots.
>
> Signed-off-by: Thomas Gleixner
> Cc: Alexander Viro
> Cc: Benjamin LaHaise
> Cc: linux-fsde...@vger.kernel.org
> Cc: linux-...@kvack.org
> Cc: Chris Mason
> C
Convert X86 to the generic kmap atomic implementation and make the
iomap_atomic() naming convention consistent while at it.
Signed-off-by: Thomas Gleixner
Cc: x...@kernel.org
---
V3: Remove the kmap_types cruft
---
arch/x86/Kconfig |3 +
arch/x86/include/asm/fixmap.h
No reason having the same code in every architecture
Signed-off-by: Thomas Gleixner
Cc: "David S. Miller"
Cc: sparcli...@vger.kernel.org
---
V3: Remove the kmap types cruft
---
arch/sparc/Kconfig |1
arch/sparc/include/asm/highmem.h|8 +-
arch/sparc/include/asm/kma
No reason having the same code in every architecture.
Signed-off-by: Thomas Gleixner
Cc: Michal Simek
---
V3: Remove the kmap types cruft
---
arch/microblaze/Kconfig |1
arch/microblaze/include/asm/fixmap.h |4 -
arch/microblaze/include/asm/highmem.h |6 ++
arch/micr
No reason having the same code in every architecture.
Signed-off-by: Thomas Gleixner
Cc: Russell King
Cc: Arnd Bergmann
Cc: linux-arm-ker...@lists.infradead.org
---
V3: Remove the kmap types cruft
---
arch/arm/Kconfig |1
arch/arm/include/asm/fixmap.h |4 -
arch/a
The kmap_atomic* interfaces in all architectures are pretty much the same
except for post map operations (flush) and pre- and post unmap operations.
Provide a generic variant for that.
Signed-off-by: Thomas Gleixner
Cc: Andrew Morton
Cc: linux...@kvack.org
---
V3: Do not reuse the kmap_atomic_i
No reason having the same code in every architecture
Signed-off-by: Thomas Gleixner
Cc: Chris Zankel
Cc: Max Filippov
Cc: linux-xte...@linux-xtensa.org
---
V3: Remove the kmap types cruft
---
arch/xtensa/Kconfig |1
arch/xtensa/include/asm/fixmap.h |4 +--
arch/xtensa/i
No reason having the same code in every architecture
Signed-off-by: Thomas Gleixner
Cc: Thomas Bogendoerfer
Cc: linux-m...@vger.kernel.org
---
V3: Remove the kmap types cruft
---
arch/mips/Kconfig |1
arch/mips/include/asm/fixmap.h |4 -
arch/mips/include/asm/highm
Switch the atomic iomap implementation over to kmap_local and stick the
preempt/pagefault mechanics into the generic code similar to the
kmap_atomic variants.
Rename the x86 map function in preparation for a non-atomic variant.
Signed-off-by: Thomas Gleixner
---
V2: New patch to make review easi
No more users. Get rid of it and remove the traces in documentation.
Signed-off-by: Thomas Gleixner
---
V3: New patch
---
Documentation/driver-api/io-mapping.rst | 22 +---
include/linux/io-mapping.h | 42 +---
2 files changed, 9 insertion
No reason having the same code in every architecture.
Signed-off-by: Thomas Gleixner
Cc: linux-c...@vger.kernel.org
---
V3: Does not compile with gcc 10
---
arch/csky/Kconfig |1
arch/csky/include/asm/fixmap.h |4 +-
arch/csky/include/asm/highmem.h |6 ++-
arch/csky/m
The implementation details in the documentation are outdated and not really
helpful. Remove them.
Signed-off-by: Thomas Gleixner
---
V3: New patch
---
Documentation/driver-api/io-mapping.rst | 22 --
1 file changed, 22 deletions(-)
--- a/Documentation/driver-api/io-mapping
The mapping code is odd and looks broken. See FIXME in the comment.
Also fix the harmless off by one in the FIX_KMAP_END define.
Signed-off-by: Thomas Gleixner
Cc: Nick Hu
Cc: Greentime Hu
Cc: Vincent Chen
---
V3: Remove the kmap types cruft
---
arch/nds32/Kconfig.cpu |1
arch
Now that the kmap atomic index is stored in task struct provide a
preemptible variant. On context switch the maps of an outgoing task are
removed and the map of the incoming task are restored. That's obviously
slow, but highmem is slow anyway.
The kmap_local.*() functions can be invoked from both
Adopt the map ordering to match the other architectures and the generic
code. Also make the maximum entries limited and not dependend on the number
of CPUs. With the original implementation did the following calculation:
nr_slots = mapsize >> PAGE_SHIFT;
The results in either 512 or 1024 total
All users gone.
Signed-off-by: Thomas Gleixner
---
include/linux/highmem.h | 63 +++-
mm/highmem.c|7 -
2 files changed, 5 insertions(+), 65 deletions(-)
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -86,31 +86,1
Replace kmap_atomic_pfn() with kmap_local_pfn() which is preemptible and
can take page faults.
Remove the indirection of the dump page and the related cruft which is not
longer required.
Signed-off-by: Thomas Gleixner
Cc: Thomas Bogendoerfer
Cc: linux-m...@vger.kernel.org
---
V3: New patch
---
Replace kmap_atomic_pfn() with kmap_local_pfn() which is preemptible and
can take page faults.
Remove the indirection of the dump page and the related cruft which is not
longer required.
Signed-off-by: Thomas Gleixner
---
V3: New patch
---
arch/x86/kernel/crash_dump_32.c | 48
Move the gory details of kmap & al into a private header and only document
the interfaces which are usable by drivers.
Signed-off-by: Thomas Gleixner
---
V3: New patch
---
include/linux/highmem-internal.h | 174 +
include/linux/highmem.h | 270 ++---
There is no reason to disable pagefaults and preemption as a side effect of
kmap_atomic_prot().
Use kmap_local_page_prot() instead and document the reasoning for the
mapping usage with the given pgprot.
Remove the NULL pointer check for the map. These functions return a valid
address for valid pa
None of these mapping requires the side effect of disabling pagefaults and
preemption.
Use io_mapping_map_local_wc() instead, and clean up gtt_user_read() and
gtt_user_write() to use a plain copy_from_user() as the local maps are not
disabling pagefaults.
Signed-off-by: Thomas Gleixner
Cc: Jani
There is no reason to disable pagefaults and preemption as a side effect of
kmap_atomic_prot().
Use kmap_local_page_prot() instead and document the reasoning for the
mapping usage with the given pgprot.
Remove the NULL pointer check for the map. These functions return a valid
address for valid pa
No more users.
Signed-off-by: Thomas Gleixner
---
V3: New patch
---
include/linux/highmem-internal.h | 12
1 file changed, 12 deletions(-)
--- a/include/linux/highmem-internal.h
+++ b/include/linux/highmem-internal.h
@@ -99,13 +99,6 @@ static inline void *kmap_atomic(struct p
None of these mapping requires the side effect of disabling pagefaults and
preemption.
Use io_mapping_map_local_wc() instead, rename the related functions
accordingly and clean up qxl_process_single_command() to use a plain
copy_from_user() as the local maps are not disabling pagefaults.
Signed-o
The header is not longer used and on alpha, ia64, openrisc, parisc and um
it was completely unused anyway as these architectures have no highmem
support.
Signed-off-by: Thomas Gleixner
---
V3: New patch
---
arch/alpha/include/asm/kmap_types.h | 15 ---
arch/ia64/include/asm/kmap_t
No more users.
Signed-off-by: Thomas Gleixner
---
V3: New patch
---
include/linux/highmem-internal.h | 14 ++
1 file changed, 2 insertions(+), 12 deletions(-)
--- a/include/linux/highmem-internal.h
+++ b/include/linux/highmem-internal.h
@@ -87,16 +87,11 @@ static inline void __kun
Now that the scheduler can deal with migrate disable properly, there is no
real compelling reason to make it only available for RT.
There are quite some code pathes which needlessly disable preemption in
order to prevent migration and some constructs like kmap_atomic() enforce
it implicitly.
Maki
Instead of storing the map per CPU provide and use per task storage. That
prepares for local kmaps which are preemptible.
The context switch code is preparatory and not yet in use because
kmap_atomic() runs with preemption disabled. Will be made usable in the
next step.
The context switch logic i
There is no requirement to disable pagefaults and preemption for these
cache management mappings.
Replace kmap_atomic_pfn() with kmap_local_pfn(). This allows to remove
kmap_atomic_pfn() in the next step.
Signed-off-by: Thomas Gleixner
Cc: Russell King
Cc: linux-arm-ker...@lists.infradead.org
-
For some obscure reason when CONFIG_DEBUG_HIGHMEM is enabled the stack
depth is increased from 20 to 41. But the only thing DEBUG_HIGHMEM does is
to enable a few BUG_ON()'s in the mapping code.
That's a leftover from the historical mapping code which had fixed entries
for various purposes. DEBUG_H
Similar to kmap local provide a iomap local variant which only disables
migration, but neither disables pagefaults nor preemption.
Signed-off-by: Thomas Gleixner
---
V3: Restrict migrate disable to the 32bit mapping case and update documentation.
V2: Split out from the large combo patch and add
No reason having the same code in every architecture
Signed-off-by: Thomas Gleixner
Cc: Michael Ellerman
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: linuxppc-...@lists.ozlabs.org
---
V3: Remove the kmap types cruft
---
arch/powerpc/Kconfig |1
arch/powerpc/include/
Nothing in modules can use that.
Signed-off-by: Thomas Gleixner
Reviewed-by: Christoph Hellwig
Cc: Andrew Morton
Cc: linux...@kvack.org
---
mm/highmem.c |2 --
1 file changed, 2 deletions(-)
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -108,8 +108,6 @@ static inline wait_queue_head_t *get_pkm
Nothing uses totalhigh_pages_dec() and totalhigh_pages_set().
Signed-off-by: Thomas Gleixner
---
V3: New patch
---
include/linux/highmem.h | 10 --
1 file changed, 10 deletions(-)
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -104,21 +104,11 @@ static inline void tota
kmap_types.h is a misnomer because the old atomic MAP based array does not
exist anymore and the whole indirection of architectures including
kmap_types.h is inconinstent and does not allow to provide guard page
debugging for this misfeature.
Add a common header file which defines the mapping stac
44 matches
Mail list logo
