Disregard, the patch uses unknown field tlb->freed_tables.
-- Best regards, Konstantin Khorenko, Virtuozzo Linux Kernel Team On 06/16/2021 03:50 PM, Konstantin Khorenko wrote:
From: Peter Zijlstra <[email protected]> Aneesh reported that: tlb_flush_mmu() tlb_flush_mmu_tlbonly() tlb_flush() <-- #1 tlb_flush_mmu_free() tlb_table_flush() tlb_table_invalidate() tlb_flush_mmu_tlbonly() tlb_flush() <-- #2 does two TLBIs when tlb->fullmm, because __tlb_reset_range() will not clear tlb->end in that case. Observe that any caller to __tlb_adjust_range() also sets at least one of the tlb->freed_tables || tlb->cleared_p* bits, and those are unconditionally cleared by __tlb_reset_range(). Change the condition for actually issuing TLBI to having one of those bits set, as opposed to having tlb->end != 0. Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Signed-off-by: Aneesh Kumar K.V <[email protected]> Reported-by: "Aneesh Kumar K.V" <[email protected]> Cc: Michael Ellerman <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> https://jira.sw.ru/browse/PSBM-101300 (cherry picked from ms commit 0758cd8304942292e95a0f750c374533db378b32) Signed-off-by: Andrey Ryabinin <[email protected]> (cherry picked from vz7 commit f64be64b0e3d ("asm-generic/tlb: avoid potential double flush")) In the scope of https://jira.sw.ru/browse/PSBM-127854 Signed-off-by: Konstantin Khorenko <[email protected]> --- include/asm-generic/tlb.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index 81db3c11bb11..cdb5b3640784 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -152,7 +152,12 @@ static inline void __tlb_reset_range(struct mmu_gather *tlb) static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) { - if (!tlb->end) + /* + * Anything calling __tlb_adjust_range() also sets at least one of + * these bits. + */ + if (!(tlb->freed_tables || tlb->cleared_ptes || tlb->cleared_pmds || + tlb->cleared_puds || tlb->cleared_p4ds)) return; tlb_flush(tlb);
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