| Message ID | 20231109045908.54996-2-byungchul@sk.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Reduce TLB flushes under some specific conditions | expand |
Hi Byungchul, kernel test robot noticed the following build errors: [auto build test ERROR on tip/sched/core] [also build test ERROR on tip/x86/core tip/x86/mm linus/master v6.6 next-20231109] [cannot apply to akpm-mm/mm-everything] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Byungchul-Park/mm-rmap-Recognize-read-only-TLB-entries-during-batched-TLB-flush/20231109-163706 base: tip/sched/core patch link: https://lore.kernel.org/r/20231109045908.54996-2-byungchul%40sk.com patch subject: [v4 1/3] mm/rmap: Recognize read-only TLB entries during batched TLB flush config: arm64-randconfig-002-20231109 (https://download.01.org/0day-ci/archive/20231110/202311100429.nc4jJoNu-lkp@intel.com/config) compiler: aarch64-linux-gcc (GCC) 13.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231110/202311100429.nc4jJoNu-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202311100429.nc4jJoNu-lkp@intel.com/ All errors (new ones prefixed by >>): mm/rmap.c: In function 'fold_ubc_ro': >> mm/rmap.c:620:9: error: implicit declaration of function 'arch_tlbbatch_fold'; did you mean 'arch_tlbbatch_flush'? [-Werror=implicit-function-declaration] 620 | arch_tlbbatch_fold(&tlb_ubc->arch, &tlb_ubc_ro->arch); | ^~~~~~~~~~~~~~~~~~ | arch_tlbbatch_flush >> mm/rmap.c:626:9: error: implicit declaration of function 'arch_tlbbatch_clear'; did you mean 'arch_tlbbatch_flush'? [-Werror=implicit-function-declaration] 626 | arch_tlbbatch_clear(&tlb_ubc_ro->arch); | ^~~~~~~~~~~~~~~~~~~ | arch_tlbbatch_flush cc1: some warnings being treated as errors vim +620 mm/rmap.c 608 609 void fold_ubc_ro(void) 610 { 611 struct tlbflush_unmap_batch *tlb_ubc = ¤t->tlb_ubc; 612 struct tlbflush_unmap_batch *tlb_ubc_ro = ¤t->tlb_ubc_ro; 613 614 if (!tlb_ubc_ro->flush_required) 615 return; 616 617 /* 618 * Fold tlb_ubc_ro's data to tlb_ubc. 619 */ > 620 arch_tlbbatch_fold(&tlb_ubc->arch, &tlb_ubc_ro->arch); 621 tlb_ubc->flush_required = true; 622 623 /* 624 * Reset tlb_ubc_ro's data. 625 */ > 626 arch_tlbbatch_clear(&tlb_ubc_ro->arch); 627 tlb_ubc_ro->flush_required = false; 628 } 629
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index 25726893c6f4..5c618a8821de 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -292,6 +292,9 @@ static inline void arch_flush_tlb_batched_pending(struct mm_struct *mm) } extern void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch); +extern void arch_tlbbatch_clear(struct arch_tlbflush_unmap_batch *batch); +extern void arch_tlbbatch_fold(struct arch_tlbflush_unmap_batch *bdst, + struct arch_tlbflush_unmap_batch *bsrc); static inline bool pte_flags_need_flush(unsigned long oldflags, unsigned long newflags, diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 453ea95b667d..d3c89a3d91eb 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -1274,6 +1274,17 @@ void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch) put_cpu(); } +void arch_tlbbatch_clear(struct arch_tlbflush_unmap_batch *batch) +{ + cpumask_clear(&batch->cpumask); +} + +void arch_tlbbatch_fold(struct arch_tlbflush_unmap_batch *bdst, + struct arch_tlbflush_unmap_batch *bsrc) +{ + cpumask_or(&bdst->cpumask, &bdst->cpumask, &bsrc->cpumask); +} + /* * Blindly accessing user memory from NMI context can be dangerous * if we're in the middle of switching the current user task or diff --git a/include/linux/sched.h b/include/linux/sched.h index 77f01ac385f7..8a31527d9ed8 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1324,6 +1324,7 @@ struct task_struct { #endif struct tlbflush_unmap_batch tlb_ubc; + struct tlbflush_unmap_batch tlb_ubc_ro; /* Cache last used pipe for splice(): */ struct pipe_inode_info *splice_pipe; diff --git a/mm/internal.h b/mm/internal.h index 30cf724ddbce..9764b240e259 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -861,6 +861,7 @@ extern struct workqueue_struct *mm_percpu_wq; void try_to_unmap_flush(void); void try_to_unmap_flush_dirty(void); void flush_tlb_batched_pending(struct mm_struct *mm); +void fold_ubc_ro(void); #else static inline void try_to_unmap_flush(void) { @@ -871,6 +872,9 @@ static inline void try_to_unmap_flush_dirty(void) static inline void flush_tlb_batched_pending(struct mm_struct *mm) { } +static inline void fold_ubc_ro(void) +{ +} #endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */ extern const struct trace_print_flags pageflag_names[]; diff --git a/mm/rmap.c b/mm/rmap.c index 9f795b93cf40..c787ae94b4c6 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -605,6 +605,28 @@ struct anon_vma *folio_lock_anon_vma_read(struct folio *folio, } #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH + +void fold_ubc_ro(void) +{ + struct tlbflush_unmap_batch *tlb_ubc = ¤t->tlb_ubc; + struct tlbflush_unmap_batch *tlb_ubc_ro = ¤t->tlb_ubc_ro; + + if (!tlb_ubc_ro->flush_required) + return; + + /* + * Fold tlb_ubc_ro's data to tlb_ubc. + */ + arch_tlbbatch_fold(&tlb_ubc->arch, &tlb_ubc_ro->arch); + tlb_ubc->flush_required = true; + + /* + * Reset tlb_ubc_ro's data. + */ + arch_tlbbatch_clear(&tlb_ubc_ro->arch); + tlb_ubc_ro->flush_required = false; +} + /* * Flush TLB entries for recently unmapped pages from remote CPUs. It is * important if a PTE was dirty when it was unmapped that it's flushed @@ -615,6 +637,7 @@ void try_to_unmap_flush(void) { struct tlbflush_unmap_batch *tlb_ubc = ¤t->tlb_ubc; + fold_ubc_ro(); if (!tlb_ubc->flush_required) return; @@ -645,13 +668,18 @@ void try_to_unmap_flush_dirty(void) static void set_tlb_ubc_flush_pending(struct mm_struct *mm, pte_t pteval, unsigned long uaddr) { - struct tlbflush_unmap_batch *tlb_ubc = ¤t->tlb_ubc; + struct tlbflush_unmap_batch *tlb_ubc; int batch; bool writable = pte_dirty(pteval); if (!pte_accessible(mm, pteval)) return; + if (pte_write(pteval) || writable) + tlb_ubc = ¤t->tlb_ubc; + else + tlb_ubc = ¤t->tlb_ubc_ro; + arch_tlbbatch_add_pending(&tlb_ubc->arch, mm, uaddr); tlb_ubc->flush_required = true;
Functionally, no change. This is a preparation for migrc mechanism that requires to recognize read-only TLB entries and makes use of them to batch more aggressively. Signed-off-by: Byungchul Park <byungchul@sk.com> --- arch/x86/include/asm/tlbflush.h | 3 +++ arch/x86/mm/tlb.c | 11 +++++++++++ include/linux/sched.h | 1 + mm/internal.h | 4 ++++ mm/rmap.c | 30 +++++++++++++++++++++++++++++- 5 files changed, 48 insertions(+), 1 deletion(-)