| Message ID | 20221115031425.44640-3-yangyicong@huawei.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | arm64: support batched/deferred tlb shootdown during page reclamation | expand |
| Context | Check | Description |
|---|---|---|
| conchuod/patch_count | success | Link |
| conchuod/cover_letter | success | Series has a cover letter |
| conchuod/tree_selection | success | Guessed tree name to be for-next |
| conchuod/fixes_present | success | Fixes tag not required for -next series |
| conchuod/verify_signedoff | success | Signed-off-by tag matches author and committer |
| conchuod/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| conchuod/module_param | success | Was 0 now: 0 |
| conchuod/build_rv32_defconfig | success | Build OK |
| conchuod/build_warn_rv64 | success | Errors and warnings before: 0 this patch: 0 |
| conchuod/dtb_warn_rv64 | success | Errors and warnings before: 0 this patch: 0 |
| conchuod/header_inline | success | No static functions without inline keyword in header files |
| conchuod/checkpatch | warning | CHECK: Alignment should match open parenthesis WARNING: added, moved or deleted file(s), does MAINTAINERS need updating? |
| conchuod/source_inline | success | Was 0 now: 0 |
| conchuod/build_rv64_nommu_k210_defconfig | success | Build OK |
| conchuod/verify_fixes | success | No Fixes tag |
| conchuod/build_rv64_nommu_virt_defconfig | success | Build OK |
在 2022/11/15 上午11:14, Yicong Yang 写道: > From: Barry Song <v-songbaohua@oppo.com> > > on x86, batched and deferred tlb shootdown has lead to 90% > performance increase on tlb shootdown. on arm64, HW can do > tlb shootdown without software IPI. But sync tlbi is still > quite expensive. > > Even running a simplest program which requires swapout can > prove this is true, > #include <sys/types.h> > #include <unistd.h> > #include <sys/mman.h> > #include <string.h> > > int main() > { > #define SIZE (1 * 1024 * 1024) > volatile unsigned char *p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, > MAP_SHARED | MAP_ANONYMOUS, -1, 0); > > memset(p, 0x88, SIZE); > > for (int k = 0; k < 10000; k++) { > /* swap in */ > for (int i = 0; i < SIZE; i += 4096) { > (void)p[i]; > } > > /* swap out */ > madvise(p, SIZE, MADV_PAGEOUT); > } > } > > Perf result on snapdragon 888 with 8 cores by using zRAM > as the swap block device. > > ~ # perf record taskset -c 4 ./a.out > [ perf record: Woken up 10 times to write data ] > [ perf record: Captured and wrote 2.297 MB perf.data (60084 samples) ] > ~ # perf report > # To display the perf.data header info, please use --header/--header-only options. > # To display the perf.data header info, please use --header/--header-only options. > # > # > # Total Lost Samples: 0 > # > # Samples: 60K of event 'cycles' > # Event count (approx.): 35706225414 > # > # Overhead Command Shared Object Symbol > # ........ ....... ................. ............................................................................. > # > 21.07% a.out [kernel.kallsyms] [k] _raw_spin_unlock_irq > 8.23% a.out [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore > 6.67% a.out [kernel.kallsyms] [k] filemap_map_pages > 6.16% a.out [kernel.kallsyms] [k] __zram_bvec_write > 5.36% a.out [kernel.kallsyms] [k] ptep_clear_flush > 3.71% a.out [kernel.kallsyms] [k] _raw_spin_lock > 3.49% a.out [kernel.kallsyms] [k] memset64 > 1.63% a.out [kernel.kallsyms] [k] clear_page > 1.42% a.out [kernel.kallsyms] [k] _raw_spin_unlock > 1.26% a.out [kernel.kallsyms] [k] mod_zone_state.llvm.8525150236079521930 > 1.23% a.out [kernel.kallsyms] [k] xas_load > 1.15% a.out [kernel.kallsyms] [k] zram_slot_lock > > ptep_clear_flush() takes 5.36% CPU in the micro-benchmark > swapping in/out a page mapped by only one process. If the > page is mapped by multiple processes, typically, like more > than 100 on a phone, the overhead would be much higher as > we have to run tlb flush 100 times for one single page. > Plus, tlb flush overhead will increase with the number > of CPU cores due to the bad scalability of tlb shootdown > in HW, so those ARM64 servers should expect much higher > overhead. > > Further perf annonate shows 95% cpu time of ptep_clear_flush > is actually used by the final dsb() to wait for the completion > of tlb flush. This provides us a very good chance to leverage > the existing batched tlb in kernel. The minimum modification > is that we only send async tlbi in the first stage and we send > dsb while we have to sync in the second stage. > > With the above simplest micro benchmark, collapsed time to > finish the program decreases around 5%. > > Typical collapsed time w/o patch: > ~ # time taskset -c 4 ./a.out > 0.21user 14.34system 0:14.69elapsed > w/ patch: > ~ # time taskset -c 4 ./a.out > 0.22user 13.45system 0:13.80elapsed > > Also, Yicong Yang added the following observation. > Tested with benchmark in the commit on Kunpeng920 arm64 server, > observed an improvement around 12.5% with command > `time ./swap_bench`. > w/o w/ > real 0m13.460s 0m11.771s > user 0m0.248s 0m0.279s > sys 0m12.039s 0m11.458s > > Originally it's noticed a 16.99% overhead of ptep_clear_flush() > which has been eliminated by this patch: > > [root@localhost yang]# perf record -- ./swap_bench && perf report > [...] > 16.99% swap_bench [kernel.kallsyms] [k] ptep_clear_flush > > It is tested on 4,8,128 CPU platforms and shows to be beneficial on > large systems but may not have improvement on small systems like on > a 4 CPU platform. So make ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH depends > on CONFIG_EXPERT for this stage and only make this enabled on systems > with more than 8 CPUs. User can modify this threshold according to > their own platforms by CONFIG_NR_CPUS_FOR_BATCHED_TLB. > > Cc: Anshuman Khandual <anshuman.khandual@arm.com> > Cc: Jonathan Corbet <corbet@lwn.net> > Cc: Nadav Amit <namit@vmware.com> > Cc: Mel Gorman <mgorman@suse.de> > Tested-by: Yicong Yang <yangyicong@hisilicon.com> > Tested-by: Xin Hao <xhao@linux.alibaba.com> > Tested-by: Punit Agrawal <punit.agrawal@bytedance.com> > Signed-off-by: Barry Song <v-songbaohua@oppo.com> > Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> > Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> > --- > .../features/vm/TLB/arch-support.txt | 2 +- > arch/arm64/Kconfig | 6 +++ > arch/arm64/include/asm/tlbbatch.h | 12 +++++ > arch/arm64/include/asm/tlbflush.h | 52 ++++++++++++++++++- > arch/x86/include/asm/tlbflush.h | 3 +- > mm/rmap.c | 10 ++-- > 6 files changed, 77 insertions(+), 8 deletions(-) > create mode 100644 arch/arm64/include/asm/tlbbatch.h > > diff --git a/Documentation/features/vm/TLB/arch-support.txt b/Documentation/features/vm/TLB/arch-support.txt > index 039e4e91ada3..2caf815d7c6c 100644 > --- a/Documentation/features/vm/TLB/arch-support.txt > +++ b/Documentation/features/vm/TLB/arch-support.txt > @@ -9,7 +9,7 @@ > | alpha: | TODO | > | arc: | TODO | > | arm: | TODO | > - | arm64: | N/A | > + | arm64: | ok | > | csky: | TODO | > | hexagon: | TODO | > | ia64: | TODO | > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 505c8a1ccbe0..72975e82c7d7 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -93,6 +93,7 @@ config ARM64 > select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 > select ARCH_SUPPORTS_NUMA_BALANCING > select ARCH_SUPPORTS_PAGE_TABLE_CHECK > + select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if EXPERT > select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT > select ARCH_WANT_DEFAULT_BPF_JIT > select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT > @@ -268,6 +269,11 @@ config ARM64_CONT_PMD_SHIFT > default 5 if ARM64_16K_PAGES > default 4 > > +config ARM64_NR_CPUS_FOR_BATCHED_TLB > + int "Threshold to enable batched TLB flush" > + default 8 > + depends on ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH > + > config ARCH_MMAP_RND_BITS_MIN > default 14 if ARM64_64K_PAGES > default 16 if ARM64_16K_PAGES > diff --git a/arch/arm64/include/asm/tlbbatch.h b/arch/arm64/include/asm/tlbbatch.h > new file mode 100644 > index 000000000000..fedb0b87b8db > --- /dev/null > +++ b/arch/arm64/include/asm/tlbbatch.h > @@ -0,0 +1,12 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef _ARCH_ARM64_TLBBATCH_H > +#define _ARCH_ARM64_TLBBATCH_H > + > +struct arch_tlbflush_unmap_batch { > + /* > + * For arm64, HW can do tlb shootdown, so we don't > + * need to record cpumask for sending IPI > + */ > +}; > + > +#endif /* _ARCH_ARM64_TLBBATCH_H */ > diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h > index 412a3b9a3c25..20d12de0d231 100644 > --- a/arch/arm64/include/asm/tlbflush.h > +++ b/arch/arm64/include/asm/tlbflush.h > @@ -254,17 +254,23 @@ static inline void flush_tlb_mm(struct mm_struct *mm) > dsb(ish); > } > > -static inline void flush_tlb_page_nosync(struct vm_area_struct *vma, > +static inline void __flush_tlb_page_nosync(struct mm_struct *mm, > unsigned long uaddr) > { > unsigned long addr; > > dsb(ishst); > - addr = __TLBI_VADDR(uaddr, ASID(vma->vm_mm)); > + addr = __TLBI_VADDR(uaddr, ASID(mm)); > __tlbi(vale1is, addr); > __tlbi_user(vale1is, addr); > } > > +static inline void flush_tlb_page_nosync(struct vm_area_struct *vma, > + unsigned long uaddr) > +{ > + return __flush_tlb_page_nosync(vma->vm_mm, uaddr); > +} > + > static inline void flush_tlb_page(struct vm_area_struct *vma, > unsigned long uaddr) > { > @@ -272,6 +278,48 @@ static inline void flush_tlb_page(struct vm_area_struct *vma, > dsb(ish); > } > > +#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH > + > +static inline bool arch_tlbbatch_should_defer(struct mm_struct *mm) > +{ > + /* > + * TLB batched flush is proved to be beneficial for systems with large > + * number of CPUs, especially system with more than 8 CPUs. TLB shutdown > + * is cheap on small systems which may not need this feature. So use > + * a threshold for enabling this to avoid potential side effects on > + * these platforms. > + */ > + if (num_online_cpus() < CONFIG_ARM64_NR_CPUS_FOR_BATCHED_TLB) > + return false; > + > + /* > + * TLB flush deferral is not required on systems, which are affected with > + * ARM64_WORKAROUND_REPEAT_TLBI, as __tlbi()/__tlbi_user() implementation > + * will have two consecutive TLBI instructions with a dsb(ish) in between > + * defeating the purpose (i.e save overall 'dsb ish' cost). > + */ > +#ifdef CONFIG_ARM64_WORKAROUND_REPEAT_TLBI > + if (unlikely(cpus_have_const_cap(ARM64_WORKAROUND_REPEAT_TLBI))) > + return false; > +#endif > + > + return true; > +} > + > +static inline void arch_tlbbatch_add_mm(struct arch_tlbflush_unmap_batch *batch, > + struct mm_struct *mm, > + unsigned long uaddr) > +{ > + __flush_tlb_page_nosync(mm, uaddr); > +} > + > +static inline void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch) > +{ > + dsb(ish); > +} > + > +#endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */ > + > /* > * This is meant to avoid soft lock-ups on large TLB flushing ranges and not > * necessarily a performance improvement. > diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h > index 8a497d902c16..5bd78ae55cd4 100644 > --- a/arch/x86/include/asm/tlbflush.h > +++ b/arch/x86/include/asm/tlbflush.h > @@ -264,7 +264,8 @@ static inline u64 inc_mm_tlb_gen(struct mm_struct *mm) > } > > static inline void arch_tlbbatch_add_mm(struct arch_tlbflush_unmap_batch *batch, > - struct mm_struct *mm) > + struct mm_struct *mm, > + unsigned long uaddr) > { > inc_mm_tlb_gen(mm); > cpumask_or(&batch->cpumask, &batch->cpumask, mm_cpumask(mm)); > diff --git a/mm/rmap.c b/mm/rmap.c > index a9ab10bc0144..a1b408ff44e5 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -640,12 +640,13 @@ void try_to_unmap_flush_dirty(void) > #define TLB_FLUSH_BATCH_PENDING_LARGE \ > (TLB_FLUSH_BATCH_PENDING_MASK / 2) > > -static void set_tlb_ubc_flush_pending(struct mm_struct *mm, bool writable) > +static void set_tlb_ubc_flush_pending(struct mm_struct *mm, bool writable, > + unsigned long uaddr) > { > struct tlbflush_unmap_batch *tlb_ubc = ¤t->tlb_ubc; > int batch, nbatch; > > - arch_tlbbatch_add_mm(&tlb_ubc->arch, mm); > + arch_tlbbatch_add_mm(&tlb_ubc->arch, mm, uaddr); > tlb_ubc->flush_required = true; > > /* > @@ -723,7 +724,8 @@ void flush_tlb_batched_pending(struct mm_struct *mm) > } > } > #else > -static void set_tlb_ubc_flush_pending(struct mm_struct *mm, bool writable) > +static void set_tlb_ubc_flush_pending(struct mm_struct *mm, bool writable, > + unsigned long uaddr) > { > } > > @@ -1596,7 +1598,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, > */ > pteval = ptep_get_and_clear(mm, address, pvmw.pte); > > - set_tlb_ubc_flush_pending(mm, pte_dirty(pteval)); > + set_tlb_ubc_flush_pending(mm, pte_dirty(pteval), address); > } else { > pteval = ptep_clear_flush(vma, address, pvmw.pte); > } Nice work, thanks. Reviewed-by: Xin Hao <xhao@linux.alibaba.com>
On Nov 14, 2022, at 7:14 PM, Yicong Yang <yangyicong@huawei.com> wrote: > diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h > index 8a497d902c16..5bd78ae55cd4 100644 > --- a/arch/x86/include/asm/tlbflush.h > +++ b/arch/x86/include/asm/tlbflush.h > @@ -264,7 +264,8 @@ static inline u64 inc_mm_tlb_gen(struct mm_struct *mm) > } > > static inline void arch_tlbbatch_add_mm(struct arch_tlbflush_unmap_batch *batch, > - struct mm_struct *mm) > + struct mm_struct *mm, > + unsigned long uaddr) Logic-wise it looks fine. I notice the “v6", and it should not be blocking, but I would note that the name "arch_tlbbatch_add_mm()” does not make much sense once the function also takes an address. It could’ve been something like arch_set_tlb_ubc_flush_pending() but that’s too long. I’m not very good with naming, but the current name is not great.
On 2022/11/16 7:38, Nadav Amit wrote: > On Nov 14, 2022, at 7:14 PM, Yicong Yang <yangyicong@huawei.com> wrote: > >> diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h >> index 8a497d902c16..5bd78ae55cd4 100644 >> --- a/arch/x86/include/asm/tlbflush.h >> +++ b/arch/x86/include/asm/tlbflush.h >> @@ -264,7 +264,8 @@ static inline u64 inc_mm_tlb_gen(struct mm_struct *mm) >> } >> >> static inline void arch_tlbbatch_add_mm(struct arch_tlbflush_unmap_batch *batch, >> - struct mm_struct *mm) >> + struct mm_struct *mm, >> + unsigned long uaddr) > > Logic-wise it looks fine. I notice the “v6", and it should not be blocking, > but I would note that the name "arch_tlbbatch_add_mm()” does not make much > sense once the function also takes an address. > ok the add_mm should still apply to x86 since the address is not used, but not for arm64. > It could’ve been something like arch_set_tlb_ubc_flush_pending() but that’s > too long. I’m not very good with naming, but the current name is not great. > What about arch_tlbbatch_add_pending()? Considering the x86 is pending the flush operation while arm64 is pending the sychronization operation, arch_tlbbatch_add_pending() should make sense to both. Thanks.
On Nov 15, 2022, at 5:50 PM, Yicong Yang <yangyicong@huawei.com> wrote: > !! External Email > > On 2022/11/16 7:38, Nadav Amit wrote: >> On Nov 14, 2022, at 7:14 PM, Yicong Yang <yangyicong@huawei.com> wrote: >> >>> diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h >>> index 8a497d902c16..5bd78ae55cd4 100644 >>> --- a/arch/x86/include/asm/tlbflush.h >>> +++ b/arch/x86/include/asm/tlbflush.h >>> @@ -264,7 +264,8 @@ static inline u64 inc_mm_tlb_gen(struct mm_struct *mm) >>> } >>> >>> static inline void arch_tlbbatch_add_mm(struct arch_tlbflush_unmap_batch *batch, >>> - struct mm_struct *mm) >>> + struct mm_struct *mm, >>> + unsigned long uaddr) >> >> Logic-wise it looks fine. I notice the “v6", and it should not be blocking, >> but I would note that the name "arch_tlbbatch_add_mm()” does not make much >> sense once the function also takes an address. > > ok the add_mm should still apply to x86 since the address is not used, but not for arm64. > >> It could’ve been something like arch_set_tlb_ubc_flush_pending() but that’s >> too long. I’m not very good with naming, but the current name is not great. > > What about arch_tlbbatch_add_pending()? Considering the x86 is pending the flush operation > while arm64 is pending the sychronization operation, arch_tlbbatch_add_pending() should > make sense to both. Sounds reasonable. Thanks.
On 11/16/22 07:26, Nadav Amit wrote: > On Nov 15, 2022, at 5:50 PM, Yicong Yang <yangyicong@huawei.com> wrote: > >> !! External Email >> >> On 2022/11/16 7:38, Nadav Amit wrote: >>> On Nov 14, 2022, at 7:14 PM, Yicong Yang <yangyicong@huawei.com> wrote: >>> >>>> diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h >>>> index 8a497d902c16..5bd78ae55cd4 100644 >>>> --- a/arch/x86/include/asm/tlbflush.h >>>> +++ b/arch/x86/include/asm/tlbflush.h >>>> @@ -264,7 +264,8 @@ static inline u64 inc_mm_tlb_gen(struct mm_struct *mm) >>>> } >>>> >>>> static inline void arch_tlbbatch_add_mm(struct arch_tlbflush_unmap_batch *batch, >>>> - struct mm_struct *mm) >>>> + struct mm_struct *mm, >>>> + unsigned long uaddr) >>> >>> Logic-wise it looks fine. I notice the “v6", and it should not be blocking, >>> but I would note that the name "arch_tlbbatch_add_mm()” does not make much >>> sense once the function also takes an address. >> >> ok the add_mm should still apply to x86 since the address is not used, but not for arm64. >> >>> It could’ve been something like arch_set_tlb_ubc_flush_pending() but that’s >>> too long. I’m not very good with naming, but the current name is not great. >> >> What about arch_tlbbatch_add_pending()? Considering the x86 is pending the flush operation >> while arm64 is pending the sychronization operation, arch_tlbbatch_add_pending() should >> make sense to both. > > Sounds reasonable. Thanks. +1, agreed.
diff --git a/Documentation/features/vm/TLB/arch-support.txt b/Documentation/features/vm/TLB/arch-support.txt index 039e4e91ada3..2caf815d7c6c 100644 --- a/Documentation/features/vm/TLB/arch-support.txt +++ b/Documentation/features/vm/TLB/arch-support.txt @@ -9,7 +9,7 @@ | alpha: | TODO | | arc: | TODO | | arm: | TODO | - | arm64: | N/A | + | arm64: | ok | | csky: | TODO | | hexagon: | TODO | | ia64: | TODO | diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 505c8a1ccbe0..72975e82c7d7 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -93,6 +93,7 @@ config ARM64 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 select ARCH_SUPPORTS_NUMA_BALANCING select ARCH_SUPPORTS_PAGE_TABLE_CHECK + select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH if EXPERT select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT select ARCH_WANT_DEFAULT_BPF_JIT select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT @@ -268,6 +269,11 @@ config ARM64_CONT_PMD_SHIFT default 5 if ARM64_16K_PAGES default 4 +config ARM64_NR_CPUS_FOR_BATCHED_TLB + int "Threshold to enable batched TLB flush" + default 8 + depends on ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH + config ARCH_MMAP_RND_BITS_MIN default 14 if ARM64_64K_PAGES default 16 if ARM64_16K_PAGES diff --git a/arch/arm64/include/asm/tlbbatch.h b/arch/arm64/include/asm/tlbbatch.h new file mode 100644 index 000000000000..fedb0b87b8db --- /dev/null +++ b/arch/arm64/include/asm/tlbbatch.h @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ARCH_ARM64_TLBBATCH_H +#define _ARCH_ARM64_TLBBATCH_H + +struct arch_tlbflush_unmap_batch { + /* + * For arm64, HW can do tlb shootdown, so we don't + * need to record cpumask for sending IPI + */ +}; + +#endif /* _ARCH_ARM64_TLBBATCH_H */ diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h index 412a3b9a3c25..20d12de0d231 100644 --- a/arch/arm64/include/asm/tlbflush.h +++ b/arch/arm64/include/asm/tlbflush.h @@ -254,17 +254,23 @@ static inline void flush_tlb_mm(struct mm_struct *mm) dsb(ish); } -static inline void flush_tlb_page_nosync(struct vm_area_struct *vma, +static inline void __flush_tlb_page_nosync(struct mm_struct *mm, unsigned long uaddr) { unsigned long addr; dsb(ishst); - addr = __TLBI_VADDR(uaddr, ASID(vma->vm_mm)); + addr = __TLBI_VADDR(uaddr, ASID(mm)); __tlbi(vale1is, addr); __tlbi_user(vale1is, addr); } +static inline void flush_tlb_page_nosync(struct vm_area_struct *vma, + unsigned long uaddr) +{ + return __flush_tlb_page_nosync(vma->vm_mm, uaddr); +} + static inline void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr) { @@ -272,6 +278,48 @@ static inline void flush_tlb_page(struct vm_area_struct *vma, dsb(ish); } +#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH + +static inline bool arch_tlbbatch_should_defer(struct mm_struct *mm) +{ + /* + * TLB batched flush is proved to be beneficial for systems with large + * number of CPUs, especially system with more than 8 CPUs. TLB shutdown + * is cheap on small systems which may not need this feature. So use + * a threshold for enabling this to avoid potential side effects on + * these platforms. + */ + if (num_online_cpus() < CONFIG_ARM64_NR_CPUS_FOR_BATCHED_TLB) + return false; + + /* + * TLB flush deferral is not required on systems, which are affected with + * ARM64_WORKAROUND_REPEAT_TLBI, as __tlbi()/__tlbi_user() implementation + * will have two consecutive TLBI instructions with a dsb(ish) in between + * defeating the purpose (i.e save overall 'dsb ish' cost). + */ +#ifdef CONFIG_ARM64_WORKAROUND_REPEAT_TLBI + if (unlikely(cpus_have_const_cap(ARM64_WORKAROUND_REPEAT_TLBI))) + return false; +#endif + + return true; +} + +static inline void arch_tlbbatch_add_mm(struct arch_tlbflush_unmap_batch *batch, + struct mm_struct *mm, + unsigned long uaddr) +{ + __flush_tlb_page_nosync(mm, uaddr); +} + +static inline void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch) +{ + dsb(ish); +} + +#endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */ + /* * This is meant to avoid soft lock-ups on large TLB flushing ranges and not * necessarily a performance improvement. diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index 8a497d902c16..5bd78ae55cd4 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -264,7 +264,8 @@ static inline u64 inc_mm_tlb_gen(struct mm_struct *mm) } static inline void arch_tlbbatch_add_mm(struct arch_tlbflush_unmap_batch *batch, - struct mm_struct *mm) + struct mm_struct *mm, + unsigned long uaddr) { inc_mm_tlb_gen(mm); cpumask_or(&batch->cpumask, &batch->cpumask, mm_cpumask(mm)); diff --git a/mm/rmap.c b/mm/rmap.c index a9ab10bc0144..a1b408ff44e5 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -640,12 +640,13 @@ void try_to_unmap_flush_dirty(void) #define TLB_FLUSH_BATCH_PENDING_LARGE \ (TLB_FLUSH_BATCH_PENDING_MASK / 2) -static void set_tlb_ubc_flush_pending(struct mm_struct *mm, bool writable) +static void set_tlb_ubc_flush_pending(struct mm_struct *mm, bool writable, + unsigned long uaddr) { struct tlbflush_unmap_batch *tlb_ubc = ¤t->tlb_ubc; int batch, nbatch; - arch_tlbbatch_add_mm(&tlb_ubc->arch, mm); + arch_tlbbatch_add_mm(&tlb_ubc->arch, mm, uaddr); tlb_ubc->flush_required = true; /* @@ -723,7 +724,8 @@ void flush_tlb_batched_pending(struct mm_struct *mm) } } #else -static void set_tlb_ubc_flush_pending(struct mm_struct *mm, bool writable) +static void set_tlb_ubc_flush_pending(struct mm_struct *mm, bool writable, + unsigned long uaddr) { } @@ -1596,7 +1598,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, */ pteval = ptep_get_and_clear(mm, address, pvmw.pte); - set_tlb_ubc_flush_pending(mm, pte_dirty(pteval)); + set_tlb_ubc_flush_pending(mm, pte_dirty(pteval), address); } else { pteval = ptep_clear_flush(vma, address, pvmw.pte); }