diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0002-x86-mm-Make-flush_tlb_mm_range-more-predictable.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0002-x86-mm-Make-flush_tlb_mm_range-more-predictable.patch | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0002-x86-mm-Make-flush_tlb_mm_range-more-predictable.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0002-x86-mm-Make-flush_tlb_mm_range-more-predictable.patch new file mode 100644 index 00000000..125c9159 --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0002-x86-mm-Make-flush_tlb_mm_range-more-predictable.patch @@ -0,0 +1,83 @@ +From d7185b4bc1a4bb697f514e447697bd535979dac3 Mon Sep 17 00:00:00 2001 +From: Andy Lutomirski <luto@kernel.org> +Date: Sat, 22 Apr 2017 00:01:21 -0700 +Subject: [PATCH 02/14] x86/mm: Make flush_tlb_mm_range() more predictable + +commit ce27374fabf553153c3f53efcaa9bfab9216bd8c upstream. + +I'm about to rewrite the function almost completely, but first I +want to get a functional change out of the way. Currently, if +flush_tlb_mm_range() does not flush the local TLB at all, it will +never do individual page flushes on remote CPUs. This seems to be +an accident, and preserving it will be awkward. Let's change it +first so that any regressions in the rewrite will be easier to +bisect and so that the rewrite can attempt to change no visible +behavior at all. + +The fix is simple: we can simply avoid short-circuiting the +calculation of base_pages_to_flush. + +As a side effect, this also eliminates a potential corner case: if +tlb_single_page_flush_ceiling == TLB_FLUSH_ALL, flush_tlb_mm_range() +could have ended up flushing the entire address space one page at a +time. + +Signed-off-by: Andy Lutomirski <luto@kernel.org> +Acked-by: Dave Hansen <dave.hansen@intel.com> +Cc: Andrew Morton <akpm@linux-foundation.org> +Cc: Borislav Petkov <bp@alien8.de> +Cc: Brian Gerst <brgerst@gmail.com> +Cc: Denys Vlasenko <dvlasenk@redhat.com> +Cc: H. Peter Anvin <hpa@zytor.com> +Cc: Josh Poimboeuf <jpoimboe@redhat.com> +Cc: Linus Torvalds <torvalds@linux-foundation.org> +Cc: Michal Hocko <mhocko@suse.com> +Cc: Nadav Amit <namit@vmware.com> +Cc: Peter Zijlstra <peterz@infradead.org> +Cc: Rik van Riel <riel@redhat.com> +Cc: Thomas Gleixner <tglx@linutronix.de> +Link: http://lkml.kernel.org/r/4b29b771d9975aad7154c314534fec235618175a.1492844372.git.luto@kernel.org +Signed-off-by: Ingo Molnar <mingo@kernel.org> +Cc: Hugh Dickins <hughd@google.com> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + arch/x86/mm/tlb.c | 12 +++++++----- + 1 file changed, 7 insertions(+), 5 deletions(-) + +diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c +index c045051..2f9d41f 100644 +--- a/arch/x86/mm/tlb.c ++++ b/arch/x86/mm/tlb.c +@@ -340,6 +340,12 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start, + unsigned long base_pages_to_flush = TLB_FLUSH_ALL; + + preempt_disable(); ++ ++ if ((end != TLB_FLUSH_ALL) && !(vmflag & VM_HUGETLB)) ++ base_pages_to_flush = (end - start) >> PAGE_SHIFT; ++ if (base_pages_to_flush > tlb_single_page_flush_ceiling) ++ base_pages_to_flush = TLB_FLUSH_ALL; ++ + if (current->active_mm != mm) { + /* Synchronize with switch_mm. */ + smp_mb(); +@@ -356,15 +362,11 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start, + goto out; + } + +- if ((end != TLB_FLUSH_ALL) && !(vmflag & VM_HUGETLB)) +- base_pages_to_flush = (end - start) >> PAGE_SHIFT; +- + /* + * Both branches below are implicit full barriers (MOV to CR or + * INVLPG) that synchronize with switch_mm. + */ +- if (base_pages_to_flush > tlb_single_page_flush_ceiling) { +- base_pages_to_flush = TLB_FLUSH_ALL; ++ if (base_pages_to_flush == TLB_FLUSH_ALL) { + count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL); + local_flush_tlb(); + } else { +-- +2.7.4 + |