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Message-ID: <20180822154046.877071284@infradead.org>
Date: Wed, 22 Aug 2018 17:30:16 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: torvalds@...ux-foundation.org
Cc: peterz@...radead.org, luto@...nel.org, x86@...nel.org,
bp@...en8.de, will.deacon@....com, riel@...riel.com,
jannh@...gle.com, ascannell@...gle.com, dave.hansen@...el.com,
linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH 4/4] x86/mm: Only use tlb_remove_table() for paravirt
If we don't use paravirt; don't play unnecessary and complicated games
to free page-tables.
Suggested-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
arch/x86/Kconfig | 2 +-
arch/x86/hyperv/mmu.c | 2 ++
arch/x86/include/asm/paravirt.h | 5 +++++
arch/x86/include/asm/paravirt_types.h | 3 +++
arch/x86/include/asm/tlbflush.h | 3 +++
arch/x86/kernel/kvm.c | 5 ++++-
arch/x86/kernel/paravirt.c | 2 ++
arch/x86/mm/pgtable.c | 8 ++++----
arch/x86/xen/mmu_pv.c | 1 +
9 files changed, 25 insertions(+), 6 deletions(-)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -179,7 +179,7 @@ config X86
select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
- select HAVE_RCU_TABLE_FREE
+ select HAVE_RCU_TABLE_FREE if PARAVIRT
select HAVE_RCU_TABLE_INVALIDATE if HAVE_RCU_TABLE_FREE
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
--- a/arch/x86/hyperv/mmu.c
+++ b/arch/x86/hyperv/mmu.c
@@ -9,6 +9,7 @@
#include <asm/mshyperv.h>
#include <asm/msr.h>
#include <asm/tlbflush.h>
+#include <asm/tlb.h>
#define CREATE_TRACE_POINTS
#include <asm/trace/hyperv.h>
@@ -231,4 +232,5 @@ void hyperv_setup_mmu_ops(void)
pr_info("Using hypercall for remote TLB flush\n");
pv_mmu_ops.flush_tlb_others = hyperv_flush_tlb_others;
+ pv_mmu_ops.tlb_remove_table = tlb_remove_table;
}
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -309,6 +309,11 @@ static inline void flush_tlb_others(cons
PVOP_VCALL2(pv_mmu_ops.flush_tlb_others, cpumask, info);
}
+static inline void paravirt_tlb_remove_table(struct mmu_gather *tlb, void *table)
+{
+ PVOP_VCALL2(pv_mmu_ops.tlb_remove_table, tlb, table);
+}
+
static inline int paravirt_pgd_alloc(struct mm_struct *mm)
{
return PVOP_CALL1(int, pv_mmu_ops.pgd_alloc, mm);
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -54,6 +54,7 @@ struct desc_struct;
struct task_struct;
struct cpumask;
struct flush_tlb_info;
+struct mmu_gather;
/*
* Wrapper type for pointers to code which uses the non-standard
@@ -222,6 +223,8 @@ struct pv_mmu_ops {
void (*flush_tlb_others)(const struct cpumask *cpus,
const struct flush_tlb_info *info);
+ void (*tlb_remove_table)(struct mmu_gather *tlb, void *table);
+
/* Hooks for allocating and freeing a pagetable top-level */
int (*pgd_alloc)(struct mm_struct *mm);
void (*pgd_free)(struct mm_struct *mm, pgd_t *pgd);
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -552,6 +552,9 @@ extern void arch_tlbbatch_flush(struct a
#ifndef CONFIG_PARAVIRT
#define flush_tlb_others(mask, info) \
native_flush_tlb_others(mask, info)
+
+#define paravirt_tlb_remove_table(tlb, page) \
+ tlb_remove_page(tlb, (void *)(page))
#endif
#endif /* _ASM_X86_TLBFLUSH_H */
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -45,6 +45,7 @@
#include <asm/apic.h>
#include <asm/apicdef.h>
#include <asm/hypervisor.h>
+#include <asm/tlb.h>
static int kvmapf = 1;
@@ -636,8 +637,10 @@ static void __init kvm_guest_init(void)
if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
!kvm_para_has_hint(KVM_HINTS_REALTIME) &&
- kvm_para_has_feature(KVM_FEATURE_STEAL_TIME))
+ kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
pv_mmu_ops.flush_tlb_others = kvm_flush_tlb_others;
+ pv_mmu_ops.tlb_remove_table = tlb_remove_table;
+ }
if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
apic_set_eoi_write(kvm_guest_apic_eoi_write);
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -41,6 +41,7 @@
#include <asm/tlbflush.h>
#include <asm/timer.h>
#include <asm/special_insns.h>
+#include <asm/tlb.h>
/*
* nop stub, which must not clobber anything *including the stack* to
@@ -409,6 +410,7 @@ struct pv_mmu_ops pv_mmu_ops __ro_after_
.flush_tlb_kernel = native_flush_tlb_global,
.flush_tlb_one_user = native_flush_tlb_one_user,
.flush_tlb_others = native_flush_tlb_others,
+ .tlb_remove_table = (void (*)(struct mmu_gather *, void *))tlb_remove_page,
.pgd_alloc = __paravirt_pgd_alloc,
.pgd_free = paravirt_nop,
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -63,7 +63,7 @@ void ___pte_free_tlb(struct mmu_gather *
{
pgtable_page_dtor(pte);
paravirt_release_pte(page_to_pfn(pte));
- tlb_remove_table(tlb, pte);
+ paravirt_tlb_remove_table(tlb, pte);
}
#if CONFIG_PGTABLE_LEVELS > 2
@@ -79,21 +79,21 @@ void ___pmd_free_tlb(struct mmu_gather *
tlb->need_flush_all = 1;
#endif
pgtable_pmd_page_dtor(page);
- tlb_remove_table(tlb, page);
+ paravirt_tlb_remove_table(tlb, page);
}
#if CONFIG_PGTABLE_LEVELS > 3
void ___pud_free_tlb(struct mmu_gather *tlb, pud_t *pud)
{
paravirt_release_pud(__pa(pud) >> PAGE_SHIFT);
- tlb_remove_table(tlb, virt_to_page(pud));
+ paravirt_tlb_remove_table(tlb, virt_to_page(pud));
}
#if CONFIG_PGTABLE_LEVELS > 4
void ___p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d)
{
paravirt_release_p4d(__pa(p4d) >> PAGE_SHIFT);
- tlb_remove_table(tlb, virt_to_page(p4d));
+ paravirt_tlb_remove_table(tlb, virt_to_page(p4d));
}
#endif /* CONFIG_PGTABLE_LEVELS > 4 */
#endif /* CONFIG_PGTABLE_LEVELS > 3 */
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -2397,6 +2397,7 @@ static const struct pv_mmu_ops xen_mmu_o
.flush_tlb_kernel = xen_flush_tlb,
.flush_tlb_one_user = xen_flush_tlb_one_user,
.flush_tlb_others = xen_flush_tlb_others,
+ .tlb_remove_table = tlb_remove_table,
.pgd_alloc = xen_pgd_alloc,
.pgd_free = xen_pgd_free,
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