search for: kmap_local

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 preemptible and atomic context. kmap local sections disable migration to keep the resulting virtual mapping address correct, but disable neither pagefaults nor preemption. A wholesale conversion of kmap_atomic to be fully preemptible is not possible because s...

...nesting. The comment in highmem.c: * - fixmap anyhow needs a limited number of mappings. So 2M kvaddr == 256 PTE * slots across NR_CPUS would be more than sufficient (generic code defines * KM_TYPE_NR as 20). is just wrong. KM_TYPE_NR (now KM_MAX_IDX) is the number of slots per CPU because kmap_local/atomic() needs to support nested mappings (thread, softirq, interrupt). While KM_MAX_IDX might be overestimated, the above reasoning is just wrong and clearly the highmem code was never tested with any system with more than a few CPUs. Use the default number of slots and fail the build when it doe...

...1: > - drop the btrfs changes (queue up in the btrfs tree) > - drop the finaly move to jfs (can't be done without the btrfs patches) > - fix the existing minix code to properly propagate errors Grabbed. I'll split that into per-fs branches (and synchronize wrt fixes), fold the kmap_local stuff into that and push out.

kmap_atomic() is deprecated in favor of kmap_local_page() since commit f3ba3c710ac5 ("mm/highmem: Provide kmap_local*"). With kmap_local_page() the mappings are per thread, CPU local, can take page-faults, and can be called from any context (including interrupts). Furthermore, the tasks can be preempted and, when they are scheduled to ru...

...verhead on the highmem users, but highmem is slow anyway. This is not a wholesale conversion which makes kmap_atomic magically preemptible because there might be usage sites which rely on the implicit preempt disable. So this needs to be done on a case by case basis and the call sites converted to kmap_local(). Note, that this is only tested on X86 and completely untested on all other architectures (at least it compiles except on csky which does not compile with the newest cross tools from kernel.org independent of this change). The lot is available from git://git.kernel.org/pub/scm/linux/kernel/...

...verhead on the highmem users, but highmem is slow anyway. This is not a wholesale conversion which makes kmap_atomic magically preemptible because there might be usage sites which rely on the implicit preempt disable. So this needs to be done on a case by case basis and the call sites converted to kmap_local(). Note, that this is only tested on X86 and completely untested on all other architectures (at least it compiles except on csky which does not compile with the newest cross tools from kernel.org independent of this change). The lot is available from git://git.kernel.org/pub/scm/linux/kernel/...

...verhead on the highmem users, but highmem is slow anyway. This is not a wholesale conversion which makes kmap_atomic magically preemptible because there might be usage sites which rely on the implicit preempt disable. So this needs to be done on a case by case basis and the call sites converted to kmap_local(). Note, that this is only tested on X86 and completely untested on all other architectures (at least it compiles except on csky which does not compile with the newest cross tools from kernel.org independent of this change). The lot is available from git://git.kernel.org/pub/scm/linux/kernel/...

...| 1 kernel/sched/core.c | 18 +++++++ mm/highmem.c | 99 +++++++++++++++++++++++++++++++++++---- 6 files changed, 129 insertions(+), 10 deletions(-) --- a/include/linux/highmem-internal.h +++ b/include/linux/highmem-internal.h @@ -9,6 +9,16 @@ void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot); void *__kmap_local_page_prot(struct page *page, pgprot_t prot); void kunmap_local_indexed(void *vaddr); +void kmap_local_fork(struct task_struct *tsk); +void __kmap_local_sched_out(void); +void __kmap_local_sched_in(void); +static inline void kmap_asser...

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 <tglx at linutronix.de> --- V2: New patch to make review easier --- arch/x86/include/asm/...

...nd 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 stack size for all architectures. Will be used when converting architectures over to a generic kmap_local/atomic implementation. The array size is chosen with the following constraints in mind: - The deepest nest level in one context is 3 according to code inspection. - The worst case nesting for the upcoming reemptible version would be: 2 maps in task context and a fault inside...

On Tue, Nov 3, 2020 at 2:33 AM Thomas Gleixner <tglx at linutronix.de> wrote: > > +static inline void *kmap(struct page *page) > +{ > + void *addr; > + > + might_sleep(); > + if (!PageHighMem(page)) > + addr = page_address(page); > + else > + addr = kmap_high(page); > + kmap_flush_tlb((unsigned

...changes (queue up in the btrfs tree) > > - drop the finaly move to jfs (can't be done without the btrfs patches) > > - fix the existing minix code to properly propagate errors > > Grabbed. I'll split that into per-fs branches (and synchronize wrt > fixes), fold the kmap_local stuff into that and push out. BTW, do you have the check for minix_delete_entry() failure when called from minix_rename() anywhere in your tree? I don't see that in this series; I'm adding the trivial fix, hopefully that won't end up creating conflicts...

...------------------- 5 files changed, 19 insertions(+), 57 deletions(-) --- a/arch/nds32/Kconfig.cpu +++ b/arch/nds32/Kconfig.cpu @@ -157,6 +157,7 @@ config HW_SUPPORT_UNALIGNMENT_ACCESS config HIGHMEM bool "High Memory Support" depends on MMU && !CPU_CACHE_ALIASING + select KMAP_LOCAL help The address space of Andes processors is only 4 Gigabytes large and it has to accommodate user address space, kernel address --- a/arch/nds32/include/asm/fixmap.h +++ b/arch/nds32/include/asm/fixmap.h @@ -6,7 +6,7 @@ #ifdef CONFIG_HIGHMEM #include <linux/threads.h> -#includ...

...+), 99 deletions(-) --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -2719,6 +2719,7 @@ config WAR_MIPS34K_MISSED_ITLB config HIGHMEM bool "High Memory Support" depends on 32BIT && CPU_SUPPORTS_HIGHMEM && SYS_SUPPORTS_HIGHMEM && !CPU_MIPS32_3_5_EVA + select KMAP_LOCAL config CPU_SUPPORTS_HIGHMEM bool --- a/arch/mips/include/asm/fixmap.h +++ b/arch/mips/include/asm/fixmap.h @@ -17,7 +17,7 @@ #include <spaces.h> #ifdef CONFIG_HIGHMEM #include <linux/threads.h> -#include <asm/kmap_types.h> +#include <asm/kmap_size.h> #endif /* @@...

...-------- arch/powerpc/mm/mem.c | 7 --- 7 files changed, 8 insertions(+), 92 deletions(-) --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -409,6 +409,7 @@ menu "Kernel options" config HIGHMEM bool "High memory support" depends on PPC32 + select KMAP_LOCAL source "kernel/Kconfig.hz" --- a/arch/powerpc/include/asm/fixmap.h +++ b/arch/powerpc/include/asm/fixmap.h @@ -20,7 +20,7 @@ #include <asm/page.h> #ifdef CONFIG_HIGHMEM #include <linux/threads.h> -#include <asm/kmap_types.h> +#include <asm/kmap_size.h> #en...

...m/highmem.c | 121 -------------------------------------- 6 files changed, 26 insertions(+), 144 deletions(-) --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1498,6 +1498,7 @@ config HAVE_ARCH_PFN_VALID config HIGHMEM bool "High Memory Support" depends on MMU + select KMAP_LOCAL help The address space of ARM processors is only 4 Gigabytes large and it has to accommodate user address space, kernel address --- a/arch/arm/include/asm/fixmap.h +++ b/arch/arm/include/asm/fixmap.h @@ -7,14 +7,14 @@ #define FIXADDR_TOP (FIXADDR_END - PAGE_SIZE) #include <linux/p...

...hanged, 211 insertions(+), 18 deletions(-) --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -31,9 +31,16 @@ static inline void invalidate_kernel_vma #include <asm/kmap_types.h> +/* + * Outside of CONFIG_HIGHMEM to support X86 32bit iomap_atomic() cruft. + */ +#ifdef CONFIG_KMAP_LOCAL +void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot); +void *__kmap_local_page_prot(struct page *page, pgprot_t prot); +void kunmap_local_indexed(void *vaddr); +#endif + #ifdef CONFIG_HIGHMEM -extern void *kmap_atomic_high_prot(struct page *page, pgprot_t prot); -extern void kunmap_atomi...

Hi all, this series removes most users of the write_one_page API. These helpers internally call ->writepage which we are gradually removing from the kernel. Changes since v2: - more minix error handling fixes Changes since v1: - drop the btrfs changes (queue up in the btrfs tree) - drop the finaly move to jfs (can't be done without the btrfs patches) - fix the existing minix code to

...el.org/lkml/20230302113421.174582-1-sgarzare at redhat.com/ RFC v1: https://lore.kernel.org/lkml/20221214163025.103075-1-sgarzare at redhat.com/ Stefano Garzarella (8): vdpa: add bind_mm/unbind_mm callbacks vhost-vdpa: use bind_mm/unbind_mm device callbacks vringh: replace kmap_atomic() with kmap_local_page() vringh: support VA with iotlb vdpa_sim: make devices agnostic for work management vdpa_sim: use kthread worker vdpa_sim: replace the spinlock with a mutex to protect the state vdpa_sim: add support for user VA drivers/vdpa/vdpa_sim/vdpa_sim.h | 11 +- include/linux/vdpa.h...

...el.org/lkml/20230302113421.174582-1-sgarzare at redhat.com/ RFC v1: https://lore.kernel.org/lkml/20221214163025.103075-1-sgarzare at redhat.com/ Stefano Garzarella (9): vdpa: add bind_mm/unbind_mm callbacks vhost-vdpa: use bind_mm/unbind_mm device callbacks vringh: replace kmap_atomic() with kmap_local_page() vringh: define the stride used for translation vringh: support VA with iotlb vdpa_sim: make devices agnostic for work management vdpa_sim: use kthread worker vdpa_sim: replace the spinlock with a mutex to protect the state vdpa_sim: add support for user VA drivers/vdpa/vdpa_sim...