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The x86 MM changes in this cycle were: 

- Implement concurrent TLB flushes, which overlaps the local TLB flush with the
    remote TLB flush. In testing this improved sysbench performance measurably by
    a couple of percentage points, especially if TLB-heavy security mitigations
    are active.
 
  - Further micro-optimizations to improve the performance of TLB flushes.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-mm-2021-04-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 tlb updates from Ingo Molnar:
 "The x86 MM changes in this cycle were:

   - Implement concurrent TLB flushes, which overlaps the local TLB
     flush with the remote TLB flush.

     In testing this improved sysbench performance measurably by a
     couple of percentage points, especially if TLB-heavy security
     mitigations are active.

   - Further micro-optimizations to improve the performance of TLB
     flushes"

* tag 'x86-mm-2021-04-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  smp: Micro-optimize smp_call_function_many_cond()
  smp: Inline on_each_cpu_cond() and on_each_cpu()
  x86/mm/tlb: Remove unnecessary uses of the inline keyword
  cpumask: Mark functions as pure
  x86/mm/tlb: Do not make is_lazy dirty for no reason
  x86/mm/tlb: Privatize cpu_tlbstate
  x86/mm/tlb: Flush remote and local TLBs concurrently
  x86/mm/tlb: Open-code on_each_cpu_cond_mask() for tlb_is_not_lazy()
  x86/mm/tlb: Unify flush_tlb_func_local() and flush_tlb_func_remote()
  smp: Run functions concurrently in smp_call_function_many_cond()
This commit is contained in:
Linus Torvalds 2021-04-29 11:41:43 -07:00
parent d0cc7ecacb a500fc918f
commit 635de956a7
16 changed files with 294 additions and 302 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
arch/x86/hyperv/mmu.c
View File

@ -52,8 +52,8 @@ static inline int fill_gva_list(u64 gva_list[], int offset,
return gva_n - offset;
}
static void hyperv_flush_tlb_others(const struct cpumask *cpus,
const struct flush_tlb_info *info)
static void hyperv_flush_tlb_multi(const struct cpumask *cpus,
const struct flush_tlb_info *info)
{
int cpu, vcpu, gva_n, max_gvas;
struct hv_tlb_flush **flush_pcpu;
@ -61,7 +61,7 @@ static void hyperv_flush_tlb_others(const struct cpumask *cpus,
u64 status;
unsigned long flags;
trace_hyperv_mmu_flush_tlb_others(cpus, info);
trace_hyperv_mmu_flush_tlb_multi(cpus, info);
if (!hv_hypercall_pg)
goto do_native;
@ -164,7 +164,7 @@ static void hyperv_flush_tlb_others(const struct cpumask *cpus,
if (hv_result_success(status))
return;
do_native:
native_flush_tlb_others(cpus, info);
native_flush_tlb_multi(cpus, info);
}
static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
@ -239,6 +239,6 @@ void hyperv_setup_mmu_ops(void)
return;
pr_info("Using hypercall for remote TLB flush\n");
pv_ops.mmu.flush_tlb_others = hyperv_flush_tlb_others;
pv_ops.mmu.flush_tlb_multi = hyperv_flush_tlb_multi;
pv_ops.mmu.tlb_remove_table = tlb_remove_table;
}

6
arch/x86/include/asm/paravirt.h
View File

@ -63,7 +63,7 @@ static inline void slow_down_io(void)
void native_flush_tlb_local(void);
void native_flush_tlb_global(void);
void native_flush_tlb_one_user(unsigned long addr);
void native_flush_tlb_others(const struct cpumask *cpumask,
void native_flush_tlb_multi(const struct cpumask *cpumask,
const struct flush_tlb_info *info);
static inline void __flush_tlb_local(void)
@ -81,10 +81,10 @@ static inline void __flush_tlb_one_user(unsigned long addr)
PVOP_VCALL1(mmu.flush_tlb_one_user, addr);
}
static inline void __flush_tlb_others(const struct cpumask *cpumask,
static inline void __flush_tlb_multi(const struct cpumask *cpumask,
const struct flush_tlb_info *info)
{
PVOP_VCALL2(mmu.flush_tlb_others, cpumask, info);
PVOP_VCALL2(mmu.flush_tlb_multi, cpumask, info);
}
static inline void paravirt_tlb_remove_table(struct mmu_gather *tlb, void *table)

4
arch/x86/include/asm/paravirt_types.h
View File

@ -161,8 +161,8 @@ struct pv_mmu_ops {
void (*flush_tlb_user)(void);
void (*flush_tlb_kernel)(void);
void (*flush_tlb_one_user)(unsigned long addr);
void (*flush_tlb_others)(const struct cpumask *cpus,
const struct flush_tlb_info *info);
void (*flush_tlb_multi)(const struct cpumask *cpus,
const struct flush_tlb_info *info);
void (*tlb_remove_table)(struct mmu_gather *tlb, void *table);

48
arch/x86/include/asm/tlbflush.h
View File

@ -89,23 +89,6 @@ struct tlb_state {
u16 loaded_mm_asid;
u16 next_asid;
/*
* We can be in one of several states:
*
* - Actively using an mm. Our CPU's bit will be set in
* mm_cpumask(loaded_mm) and is_lazy == false;
*
* - Not using a real mm. loaded_mm == &init_mm. Our CPU's bit
* will not be set in mm_cpumask(&init_mm) and is_lazy == false.
*
* - Lazily using a real mm. loaded_mm != &init_mm, our bit
* is set in mm_cpumask(loaded_mm), but is_lazy == true.
* We're heuristically guessing that the CR3 load we
* skipped more than makes up for the overhead added by
* lazy mode.
*/
bool is_lazy;
/*
* If set we changed the page tables in such a way that we
* needed an invalidation of all contexts (aka. PCIDs / ASIDs).
@ -151,7 +134,27 @@ struct tlb_state {
*/
struct tlb_context ctxs[TLB_NR_DYN_ASIDS];
};
DECLARE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate);
DECLARE_PER_CPU_ALIGNED(struct tlb_state, cpu_tlbstate);
struct tlb_state_shared {
/*
* We can be in one of several states:
*
* - Actively using an mm. Our CPU's bit will be set in
* mm_cpumask(loaded_mm) and is_lazy == false;
*
* - Not using a real mm. loaded_mm == &init_mm. Our CPU's bit
* will not be set in mm_cpumask(&init_mm) and is_lazy == false.
*
* - Lazily using a real mm. loaded_mm != &init_mm, our bit
* is set in mm_cpumask(loaded_mm), but is_lazy == true.
* We're heuristically guessing that the CR3 load we
* skipped more than makes up for the overhead added by
* lazy mode.
*/
bool is_lazy;
};
DECLARE_PER_CPU_SHARED_ALIGNED(struct tlb_state_shared, cpu_tlbstate_shared);
bool nmi_uaccess_okay(void);
#define nmi_uaccess_okay nmi_uaccess_okay
@ -175,7 +178,7 @@ extern void initialize_tlbstate_and_flush(void);
* - flush_tlb_page(vma, vmaddr) flushes one page
* - flush_tlb_range(vma, start, end) flushes a range of pages
* - flush_tlb_kernel_range(start, end) flushes a range of kernel pages
* - flush_tlb_others(cpumask, info) flushes TLBs on other cpus
* - flush_tlb_multi(cpumask, info) flushes TLBs on multiple cpus
*
* ..but the i386 has somewhat limited tlb flushing capabilities,
* and page-granular flushes are available only on i486 and up.
@ -201,14 +204,15 @@ struct flush_tlb_info {
unsigned long start;
unsigned long end;
u64 new_tlb_gen;
unsigned int stride_shift;
bool freed_tables;
unsigned int initiating_cpu;
u8 stride_shift;
u8 freed_tables;
};
void flush_tlb_local(void);
void flush_tlb_one_user(unsigned long addr);
void flush_tlb_one_kernel(unsigned long addr);
void flush_tlb_others(const struct cpumask *cpumask,
void flush_tlb_multi(const struct cpumask *cpumask,
const struct flush_tlb_info *info);
#ifdef CONFIG_PARAVIRT

2
arch/x86/include/asm/trace/hyperv.h
View File

@ -8,7 +8,7 @@
#if IS_ENABLED(CONFIG_HYPERV)
TRACE_EVENT(hyperv_mmu_flush_tlb_others,
TRACE_EVENT(hyperv_mmu_flush_tlb_multi,
TP_PROTO(const struct cpumask *cpus,
const struct flush_tlb_info *info),
TP_ARGS(cpus, info),

2
arch/x86/kernel/alternative.c
View File

@ -706,7 +706,7 @@ static inline temp_mm_state_t use_temporary_mm(struct mm_struct *mm)
* with a stale address space WITHOUT being in lazy mode after
* restoring the previous mm.
*/
if (this_cpu_read(cpu_tlbstate.is_lazy))
if (this_cpu_read(cpu_tlbstate_shared.is_lazy))
leave_mm(smp_processor_id());
temp_state.mm = this_cpu_read(cpu_tlbstate.loaded_mm);

11
arch/x86/kernel/kvm.c
View File

@ -613,7 +613,7 @@ static int kvm_cpu_down_prepare(unsigned int cpu)
}
#endif
static void kvm_flush_tlb_others(const struct cpumask *cpumask,
static void kvm_flush_tlb_multi(const struct cpumask *cpumask,
const struct flush_tlb_info *info)
{
u8 state;
@ -627,6 +627,11 @@ static void kvm_flush_tlb_others(const struct cpumask *cpumask,
* queue flush_on_enter for pre-empted vCPUs
*/
for_each_cpu(cpu, flushmask) {
/*
* The local vCPU is never preempted, so we do not explicitly
* skip check for local vCPU - it will never be cleared from
* flushmask.
*/
src = &per_cpu(steal_time, cpu);
state = READ_ONCE(src->preempted);
if ((state & KVM_VCPU_PREEMPTED)) {
@ -636,7 +641,7 @@ static void kvm_flush_tlb_others(const struct cpumask *cpumask,
}
}
native_flush_tlb_others(flushmask, info);
native_flush_tlb_multi(flushmask, info);
}
static void __init kvm_guest_init(void)
@ -654,7 +659,7 @@ static void __init kvm_guest_init(void)
}
if (pv_tlb_flush_supported()) {
pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others;
pv_ops.mmu.flush_tlb_multi = kvm_flush_tlb_multi;
pv_ops.mmu.tlb_remove_table = tlb_remove_table;
pr_info("KVM setup pv remote TLB flush\n");
}

2
arch/x86/kernel/paravirt.c
View File

@ -291,7 +291,7 @@ struct paravirt_patch_template pv_ops = {
.mmu.flush_tlb_user = native_flush_tlb_local,
.mmu.flush_tlb_kernel = native_flush_tlb_global,
.mmu.flush_tlb_one_user = native_flush_tlb_one_user,
.mmu.flush_tlb_others = native_flush_tlb_others,
.mmu.flush_tlb_multi = native_flush_tlb_multi,
.mmu.tlb_remove_table =
(void (*)(struct mmu_gather *, void *))tlb_remove_page,

2
arch/x86/mm/init.c
View File

@ -1017,7 +1017,7 @@ void __init zone_sizes_init(void)
free_area_init(max_zone_pfns);
}
__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = {
__visible DEFINE_PER_CPU_ALIGNED(struct tlb_state, cpu_tlbstate) = {
.loaded_mm = &init_mm,
.next_asid = 1,
.cr4 = ~0UL, /* fail hard if we screw up cr4 shadow initialization */

176
arch/x86/mm/tlb.c
View File

@ -24,7 +24,7 @@
# define __flush_tlb_local native_flush_tlb_local
# define __flush_tlb_global native_flush_tlb_global
# define __flush_tlb_one_user(addr) native_flush_tlb_one_user(addr)
# define __flush_tlb_others(msk, info) native_flush_tlb_others(msk, info)
# define __flush_tlb_multi(msk, info) native_flush_tlb_multi(msk, info)
#endif
/*
@ -300,7 +300,7 @@ void leave_mm(int cpu)
return;
/* Warn if we're not lazy. */
WARN_ON(!this_cpu_read(cpu_tlbstate.is_lazy));
WARN_ON(!this_cpu_read(cpu_tlbstate_shared.is_lazy));
switch_mm(NULL, &init_mm, NULL);
}
@ -316,7 +316,7 @@ void switch_mm(struct mm_struct *prev, struct mm_struct *next,
local_irq_restore(flags);
}
static inline unsigned long mm_mangle_tif_spec_ib(struct task_struct *next)
static unsigned long mm_mangle_tif_spec_ib(struct task_struct *next)
{
unsigned long next_tif = task_thread_info(next)->flags;
unsigned long ibpb = (next_tif >> TIF_SPEC_IB) & LAST_USER_MM_IBPB;
@ -424,7 +424,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
{
struct mm_struct *real_prev = this_cpu_read(cpu_tlbstate.loaded_mm);
u16 prev_asid = this_cpu_read(cpu_tlbstate.loaded_mm_asid);
bool was_lazy = this_cpu_read(cpu_tlbstate.is_lazy);
bool was_lazy = this_cpu_read(cpu_tlbstate_shared.is_lazy);
unsigned cpu = smp_processor_id();
u64 next_tlb_gen;
bool need_flush;
@ -439,7 +439,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
* NB: leave_mm() calls us with prev == NULL and tsk == NULL.
*/
/* We don't want flush_tlb_func_* to run concurrently with us. */
/* We don't want flush_tlb_func() to run concurrently with us. */
if (IS_ENABLED(CONFIG_PROVE_LOCKING))
WARN_ON_ONCE(!irqs_disabled());
@ -469,7 +469,8 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
__flush_tlb_all();
}
#endif
this_cpu_write(cpu_tlbstate.is_lazy, false);
if (was_lazy)
this_cpu_write(cpu_tlbstate_shared.is_lazy, false);
/*
* The membarrier system call requires a full memory barrier and
@ -490,7 +491,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
/*
* Even in lazy TLB mode, the CPU should stay set in the
* mm_cpumask. The TLB shootdown code can figure out from
* from cpu_tlbstate.is_lazy whether or not to send an IPI.
* cpu_tlbstate_shared.is_lazy whether or not to send an IPI.
*/
if (WARN_ON_ONCE(real_prev != &init_mm &&
!cpumask_test_cpu(cpu, mm_cpumask(next))))
@ -598,7 +599,7 @@ void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
if (this_cpu_read(cpu_tlbstate.loaded_mm) == &init_mm)
return;
this_cpu_write(cpu_tlbstate.is_lazy, true);
this_cpu_write(cpu_tlbstate_shared.is_lazy, true);
}
/*
@ -647,14 +648,13 @@ void initialize_tlbstate_and_flush(void)
}
/*
* flush_tlb_func_common()'s memory ordering requirement is that any
* flush_tlb_func()'s memory ordering requirement is that any
* TLB fills that happen after we flush the TLB are ordered after we
* read active_mm's tlb_gen. We don't need any explicit barriers
* because all x86 flush operations are serializing and the
* atomic64_read operation won't be reordered by the compiler.
*/
static void flush_tlb_func_common(const struct flush_tlb_info *f,
bool local, enum tlb_flush_reason reason)
static void flush_tlb_func(void *info)
{
/*
* We have three different tlb_gen values in here. They are:
@ -665,28 +665,40 @@ static void flush_tlb_func_common(const struct flush_tlb_info *f,
* - f->new_tlb_gen: the generation that the requester of the flush
* wants us to catch up to.
*/
const struct flush_tlb_info *f = info;
struct mm_struct *loaded_mm = this_cpu_read(cpu_tlbstate.loaded_mm);
u32 loaded_mm_asid = this_cpu_read(cpu_tlbstate.loaded_mm_asid);
u64 mm_tlb_gen = atomic64_read(&loaded_mm->context.tlb_gen);
u64 local_tlb_gen = this_cpu_read(cpu_tlbstate.ctxs[loaded_mm_asid].tlb_gen);
bool local = smp_processor_id() == f->initiating_cpu;
unsigned long nr_invalidate = 0;
/* This code cannot presently handle being reentered. */
VM_WARN_ON(!irqs_disabled());
if (!local) {
inc_irq_stat(irq_tlb_count);
count_vm_tlb_event(NR_TLB_REMOTE_FLUSH_RECEIVED);
/* Can only happen on remote CPUs */
if (f->mm && f->mm != loaded_mm)
return;
}
if (unlikely(loaded_mm == &init_mm))
return;
VM_WARN_ON(this_cpu_read(cpu_tlbstate.ctxs[loaded_mm_asid].ctx_id) !=
loaded_mm->context.ctx_id);
if (this_cpu_read(cpu_tlbstate.is_lazy)) {
if (this_cpu_read(cpu_tlbstate_shared.is_lazy)) {
/*
* We're in lazy mode. We need to at least flush our
* paging-structure cache to avoid speculatively reading
* garbage into our TLB. Since switching to init_mm is barely
* slower than a minimal flush, just switch to init_mm.
*
* This should be rare, with native_flush_tlb_others skipping
* This should be rare, with native_flush_tlb_multi() skipping
* IPIs to lazy TLB mode CPUs.
*/
switch_mm_irqs_off(NULL, &init_mm, NULL);
@ -700,8 +712,7 @@ static void flush_tlb_func_common(const struct flush_tlb_info *f,
* be handled can catch us all the way up, leaving no work for
* the second flush.
*/
trace_tlb_flush(reason, 0);
return;
goto done;
}
WARN_ON_ONCE(local_tlb_gen > mm_tlb_gen);
@ -748,56 +759,54 @@ static void flush_tlb_func_common(const struct flush_tlb_info *f,
f->new_tlb_gen == local_tlb_gen + 1 &&
f->new_tlb_gen == mm_tlb_gen) {
/* Partial flush */
unsigned long nr_invalidate = (f->end - f->start) >> f->stride_shift;
unsigned long addr = f->start;
nr_invalidate = (f->end - f->start) >> f->stride_shift;
while (addr < f->end) {
flush_tlb_one_user(addr);
addr += 1UL << f->stride_shift;
}
if (local)
count_vm_tlb_events(NR_TLB_LOCAL_FLUSH_ONE, nr_invalidate);
trace_tlb_flush(reason, nr_invalidate);
} else {
/* Full flush. */
nr_invalidate = TLB_FLUSH_ALL;
flush_tlb_local();
if (local)
count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
trace_tlb_flush(reason, TLB_FLUSH_ALL);
}
/* Both paths above update our state to mm_tlb_gen. */
this_cpu_write(cpu_tlbstate.ctxs[loaded_mm_asid].tlb_gen, mm_tlb_gen);
/* Tracing is done in a unified manner to reduce the code size */
done:
trace_tlb_flush(!local ? TLB_REMOTE_SHOOTDOWN :
(f->mm == NULL) ? TLB_LOCAL_SHOOTDOWN :
TLB_LOCAL_MM_SHOOTDOWN,
nr_invalidate);
}
static void flush_tlb_func_local(const void *info, enum tlb_flush_reason reason)
static bool tlb_is_not_lazy(int cpu)
{
const struct flush_tlb_info *f = info;
flush_tlb_func_common(f, true, reason);
return !per_cpu(cpu_tlbstate_shared.is_lazy, cpu);
}
static void flush_tlb_func_remote(void *info)
{
const struct flush_tlb_info *f = info;
static DEFINE_PER_CPU(cpumask_t, flush_tlb_mask);
inc_irq_stat(irq_tlb_count);
DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state_shared, cpu_tlbstate_shared);
EXPORT_PER_CPU_SYMBOL(cpu_tlbstate_shared);
if (f->mm && f->mm != this_cpu_read(cpu_tlbstate.loaded_mm))
return;
count_vm_tlb_event(NR_TLB_REMOTE_FLUSH_RECEIVED);
flush_tlb_func_common(f, false, TLB_REMOTE_SHOOTDOWN);
}
static bool tlb_is_not_lazy(int cpu, void *data)
{
return !per_cpu(cpu_tlbstate.is_lazy, cpu);
}
STATIC_NOPV void native_flush_tlb_others(const struct cpumask *cpumask,
STATIC_NOPV void native_flush_tlb_multi(const struct cpumask *cpumask,
const struct flush_tlb_info *info)
{
/*
* Do accounting and tracing. Note that there are (and have always been)
* cases in which a remote TLB flush will be traced, but eventually
* would not happen.
*/
count_vm_tlb_event(NR_TLB_REMOTE_FLUSH);
if (info->end == TLB_FLUSH_ALL)
trace_tlb_flush(TLB_REMOTE_SEND_IPI, TLB_FLUSH_ALL);
@ -815,18 +824,42 @@ STATIC_NOPV void native_flush_tlb_others(const struct cpumask *cpumask,
* up on the new contents of what used to be page tables, while
* doing a speculative memory access.
*/
if (info->freed_tables)
smp_call_function_many(cpumask, flush_tlb_func_remote,
(void *)info, 1);
else
on_each_cpu_cond_mask(tlb_is_not_lazy, flush_tlb_func_remote,
(void *)info, 1, cpumask);
if (info->freed_tables) {
on_each_cpu_mask(cpumask, flush_tlb_func, (void *)info, true);
} else {
/*
* Although we could have used on_each_cpu_cond_mask(),
* open-coding it has performance advantages, as it eliminates
* the need for indirect calls or retpolines. In addition, it
* allows to use a designated cpumask for evaluating the
* condition, instead of allocating one.
*
* This code works under the assumption that there are no nested
* TLB flushes, an assumption that is already made in
* flush_tlb_mm_range().
*
* cond_cpumask is logically a stack-local variable, but it is
* more efficient to have it off the stack and not to allocate
* it on demand. Preemption is disabled and this code is
* non-reentrant.
*/
struct cpumask *cond_cpumask = this_cpu_ptr(&flush_tlb_mask);
int cpu;
cpumask_clear(cond_cpumask);
for_each_cpu(cpu, cpumask) {
if (tlb_is_not_lazy(cpu))
__cpumask_set_cpu(cpu, cond_cpumask);
}
on_each_cpu_mask(cond_cpumask, flush_tlb_func, (void *)info, true);
}
}
void flush_tlb_others(const struct cpumask *cpumask,
void flush_tlb_multi(const struct cpumask *cpumask,
const struct flush_tlb_info *info)
{
__flush_tlb_others(cpumask, info);
__flush_tlb_multi(cpumask, info);
}
/*
@ -847,7 +880,7 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(struct flush_tlb_info, flush_tlb_info);
static DEFINE_PER_CPU(unsigned int, flush_tlb_info_idx);
#endif
static inline struct flush_tlb_info *get_flush_tlb_info(struct mm_struct *mm,
static struct flush_tlb_info *get_flush_tlb_info(struct mm_struct *mm,
unsigned long start, unsigned long end,
unsigned int stride_shift, bool freed_tables,
u64 new_tlb_gen)
@ -869,11 +902,12 @@ static inline struct flush_tlb_info *get_flush_tlb_info(struct mm_struct *mm,
info->stride_shift = stride_shift;
info->freed_tables = freed_tables;
info->new_tlb_gen = new_tlb_gen;
info->initiating_cpu = smp_processor_id();
return info;
}
static inline void put_flush_tlb_info(void)
static void put_flush_tlb_info(void)
{
#ifdef CONFIG_DEBUG_VM
/* Complete reentrancy prevention checks */
@ -905,16 +939,20 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
info = get_flush_tlb_info(mm, start, end, stride_shift, freed_tables,
new_tlb_gen);
if (mm == this_cpu_read(cpu_tlbstate.loaded_mm)) {
/*
* flush_tlb_multi() is not optimized for the common case in which only
* a local TLB flush is needed. Optimize this use-case by calling
* flush_tlb_func_local() directly in this case.
*/
if (cpumask_any_but(mm_cpumask(mm), cpu) < nr_cpu_ids) {
flush_tlb_multi(mm_cpumask(mm), info);
} else if (mm == this_cpu_read(cpu_tlbstate.loaded_mm)) {
lockdep_assert_irqs_enabled();
local_irq_disable();
flush_tlb_func_local(info, TLB_LOCAL_MM_SHOOTDOWN);
flush_tlb_func(info);
local_irq_enable();
}
if (cpumask_any_but(mm_cpumask(mm), cpu) < nr_cpu_ids)
flush_tlb_others(mm_cpumask(mm), info);
put_flush_tlb_info();
put_cpu();
}
@ -1119,34 +1157,30 @@ void __flush_tlb_all(void)
}
EXPORT_SYMBOL_GPL(__flush_tlb_all);
/*
* arch_tlbbatch_flush() performs a full TLB flush regardless of the active mm.
* This means that the 'struct flush_tlb_info' that describes which mappings to
* flush is actually fixed. We therefore set a single fixed struct and use it in
* arch_tlbbatch_flush().
*/
static const struct flush_tlb_info full_flush_tlb_info = {
.mm = NULL,
.start = 0,
.end = TLB_FLUSH_ALL,
};
void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
{
struct flush_tlb_info *info;
int cpu = get_cpu();
if (cpumask_test_cpu(cpu, &batch->cpumask)) {
info = get_flush_tlb_info(NULL, 0, TLB_FLUSH_ALL, 0, false, 0);
/*
* flush_tlb_multi() is not optimized for the common case in which only
* a local TLB flush is needed. Optimize this use-case by calling
* flush_tlb_func_local() directly in this case.
*/
if (cpumask_any_but(&batch->cpumask, cpu) < nr_cpu_ids) {
flush_tlb_multi(&batch->cpumask, info);
} else if (cpumask_test_cpu(cpu, &batch->cpumask)) {
lockdep_assert_irqs_enabled();
local_irq_disable();
flush_tlb_func_local(&full_flush_tlb_info, TLB_LOCAL_SHOOTDOWN);
flush_tlb_func(info);
local_irq_enable();
}
if (cpumask_any_but(&batch->cpumask, cpu) < nr_cpu_ids)
flush_tlb_others(&batch->cpumask, &full_flush_tlb_info);
cpumask_clear(&batch->cpumask);
put_flush_tlb_info();
put_cpu();
}

11
arch/x86/xen/mmu_pv.c
View File

@ -1247,8 +1247,8 @@ static void xen_flush_tlb_one_user(unsigned long addr)
preempt_enable();
}
static void xen_flush_tlb_others(const struct cpumask *cpus,
const struct flush_tlb_info *info)
static void xen_flush_tlb_multi(const struct cpumask *cpus,
const struct flush_tlb_info *info)
{
struct {
struct mmuext_op op;
@ -1258,7 +1258,7 @@ static void xen_flush_tlb_others(const struct cpumask *cpus,
const size_t mc_entry_size = sizeof(args->op) +
sizeof(args->mask[0]) * BITS_TO_LONGS(num_possible_cpus());
trace_xen_mmu_flush_tlb_others(cpus, info->mm, info->start, info->end);
trace_xen_mmu_flush_tlb_multi(cpus, info->mm, info->start, info->end);
if (cpumask_empty(cpus))
return; /* nothing to do */
@ -1267,9 +1267,8 @@ static void xen_flush_tlb_others(const struct cpumask *cpus,
args = mcs.args;
args->op.arg2.vcpumask = to_cpumask(args->mask);
/* Remove us, and any offline CPUS. */
/* Remove any offline CPUs */
cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask));
args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
if (info->end != TLB_FLUSH_ALL &&
@ -2086,7 +2085,7 @@ static const struct pv_mmu_ops xen_mmu_ops __initconst = {
.flush_tlb_user = xen_flush_tlb,
.flush_tlb_kernel = xen_flush_tlb,
.flush_tlb_one_user = xen_flush_tlb_one_user,
.flush_tlb_others = xen_flush_tlb_others,
.flush_tlb_multi = xen_flush_tlb_multi,
.tlb_remove_table = tlb_remove_table,
.pgd_alloc = xen_pgd_alloc,

6
include/linux/cpumask.h
View File

@ -206,7 +206,7 @@ static inline unsigned int cpumask_last(const struct cpumask *srcp)
return find_last_bit(cpumask_bits(srcp), nr_cpumask_bits);
}
unsigned int cpumask_next(int n, const struct cpumask *srcp);
unsigned int __pure cpumask_next(int n, const struct cpumask *srcp);
/**
* cpumask_next_zero - get the next unset cpu in a cpumask
@ -223,8 +223,8 @@ static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp)
return find_next_zero_bit(cpumask_bits(srcp), nr_cpumask_bits, n+1);
}
int cpumask_next_and(int n, const struct cpumask *, const struct cpumask *);
int cpumask_any_but(const struct cpumask *mask, unsigned int cpu);
int __pure cpumask_next_and(int n, const struct cpumask *, const struct cpumask *);
int __pure cpumask_any_but(const struct cpumask *mask, unsigned int cpu);
unsigned int cpumask_local_spread(unsigned int i, int node);
int cpumask_any_and_distribute(const struct cpumask *src1p,
const struct cpumask *src2p);

62
include/linux/smp.h
View File

@ -50,31 +50,53 @@ extern unsigned int total_cpus;
int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
int wait);
/*
* Call a function on all processors
*/
void on_each_cpu(smp_call_func_t func, void *info, int wait);
/*
* Call a function on processors specified by mask, which might include
* the local one.
*/
void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
void *info, bool wait);
/*
* Call a function on each processor for which the supplied function
* cond_func returns a positive value. This may include the local
* processor.
*/
void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func,
void *info, bool wait);
void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
void *info, bool wait, const struct cpumask *mask);
int smp_call_function_single_async(int cpu, call_single_data_t *csd);
/*
* Call a function on all processors
*/
static inline void on_each_cpu(smp_call_func_t func, void *info, int wait)
{
on_each_cpu_cond_mask(NULL, func, info, wait, cpu_online_mask);
}
/**
* on_each_cpu_mask(): Run a function on processors specified by
* cpumask, which may include the local processor.
* @mask: The set of cpus to run on (only runs on online subset).
* @func: The function to run. This must be fast and non-blocking.
* @info: An arbitrary pointer to pass to the function.
* @wait: If true, wait (atomically) until function has completed
* on other CPUs.
*
* If @wait is true, then returns once @func has returned.
*
* You must not call this function with disabled interrupts or from a
* hardware interrupt handler or from a bottom half handler. The
* exception is that it may be used during early boot while
* early_boot_irqs_disabled is set.
*/
static inline void on_each_cpu_mask(const struct cpumask *mask,
smp_call_func_t func, void *info, bool wait)
{
on_each_cpu_cond_mask(NULL, func, info, wait, mask);
}
/*
* Call a function on each processor for which the supplied function
* cond_func returns a positive value. This may include the local
* processor. May be used during early boot while early_boot_irqs_disabled is
* set. Use local_irq_save/restore() instead of local_irq_disable/enable().
*/
static inline void on_each_cpu_cond(smp_cond_func_t cond_func,
smp_call_func_t func, void *info, bool wait)
{
on_each_cpu_cond_mask(cond_func, func, info, wait, cpu_online_mask);
}
#ifdef CONFIG_SMP
#include <linux/preempt.h>

2
include/trace/events/xen.h
View File

@ -346,7 +346,7 @@ TRACE_EVENT(xen_mmu_flush_tlb_one_user,
TP_printk("addr %lx", __entry->addr)
);
TRACE_EVENT(xen_mmu_flush_tlb_others,
TRACE_EVENT(xen_mmu_flush_tlb_multi,
TP_PROTO(const struct cpumask *cpus, struct mm_struct *mm,
unsigned long addr, unsigned long end),
TP_ARGS(cpus, mm, addr, end),

214
kernel/smp.c
View File

@ -850,12 +850,28 @@ int smp_call_function_any(const struct cpumask *mask,
}
EXPORT_SYMBOL_GPL(smp_call_function_any);
/*
* Flags to be used as scf_flags argument of smp_call_function_many_cond().
*
* %SCF_WAIT: Wait until function execution is completed
* %SCF_RUN_LOCAL: Run also locally if local cpu is set in cpumask
*/
#define SCF_WAIT (1U << 0)
#define SCF_RUN_LOCAL (1U << 1)
static void smp_call_function_many_cond(const struct cpumask *mask,
smp_call_func_t func, void *info,
bool wait, smp_cond_func_t cond_func)
unsigned int scf_flags,
smp_cond_func_t cond_func)
{
int cpu, last_cpu, this_cpu = smp_processor_id();
struct call_function_data *cfd;
int cpu, next_cpu, this_cpu = smp_processor_id();
bool wait = scf_flags & SCF_WAIT;
bool run_remote = false;
bool run_local = false;
int nr_cpus = 0;
lockdep_assert_preemption_disabled();
/*
* Can deadlock when called with interrupts disabled.
@ -863,8 +879,9 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
* send smp call function interrupt to this cpu and as such deadlocks
* can't happen.
*/
WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
&& !oops_in_progress && !early_boot_irqs_disabled);
if (cpu_online(this_cpu) && !oops_in_progress &&
!early_boot_irqs_disabled)
lockdep_assert_irqs_enabled();
/*
* When @wait we can deadlock when we interrupt between llist_add() and
@ -874,70 +891,75 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
*/
WARN_ON_ONCE(!in_task());
/* Try to fastpath. So, what's a CPU they want? Ignoring this one. */
/* Check if we need local execution. */
if ((scf_flags & SCF_RUN_LOCAL) && cpumask_test_cpu(this_cpu, mask))
run_local = true;
/* Check if we need remote execution, i.e., any CPU excluding this one. */
cpu = cpumask_first_and(mask, cpu_online_mask);
if (cpu == this_cpu)
cpu = cpumask_next_and(cpu, mask, cpu_online_mask);
if (cpu < nr_cpu_ids)
run_remote = true;
/* No online cpus? We're done. */
if (cpu >= nr_cpu_ids)
return;
if (run_remote) {
cfd = this_cpu_ptr(&cfd_data);
cpumask_and(cfd->cpumask, mask, cpu_online_mask);
__cpumask_clear_cpu(this_cpu, cfd->cpumask);
/* Do we have another CPU which isn't us? */
next_cpu = cpumask_next_and(cpu, mask, cpu_online_mask);
if (next_cpu == this_cpu)
next_cpu = cpumask_next_and(next_cpu, mask, cpu_online_mask);
cpumask_clear(cfd->cpumask_ipi);
for_each_cpu(cpu, cfd->cpumask) {
struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
call_single_data_t *csd = &pcpu->csd;
/* Fastpath: do that cpu by itself. */
if (next_cpu >= nr_cpu_ids) {
if (!cond_func || cond_func(cpu, info))
smp_call_function_single(cpu, func, info, wait);
return;
}
if (cond_func && !cond_func(cpu, info))
continue;
cfd = this_cpu_ptr(&cfd_data);
cpumask_and(cfd->cpumask, mask, cpu_online_mask);
__cpumask_clear_cpu(this_cpu, cfd->cpumask);
/* Some callers race with other cpus changing the passed mask */
if (unlikely(!cpumask_weight(cfd->cpumask)))
return;
cpumask_clear(cfd->cpumask_ipi);
for_each_cpu(cpu, cfd->cpumask) {
struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
call_single_data_t *csd = &pcpu->csd;
if (cond_func && !cond_func(cpu, info))
continue;
csd_lock(csd);
if (wait)
csd->node.u_flags |= CSD_TYPE_SYNC;
csd->func = func;
csd->info = info;
csd_lock(csd);
if (wait)
csd->node.u_flags |= CSD_TYPE_SYNC;
csd->func = func;
csd->info = info;
#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
csd->node.src = smp_processor_id();
csd->node.dst = cpu;
csd->node.src = smp_processor_id();
csd->node.dst = cpu;
#endif
cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
if (llist_add(&csd->node.llist, &per_cpu(call_single_queue, cpu))) {
__cpumask_set_cpu(cpu, cfd->cpumask_ipi);
cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
} else {
cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI);
cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
if (llist_add(&csd->node.llist, &per_cpu(call_single_queue, cpu))) {
__cpumask_set_cpu(cpu, cfd->cpumask_ipi);
nr_cpus++;
last_cpu = cpu;
cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
} else {
cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI);
}
}
cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->ping, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PING);
/*
* Choose the most efficient way to send an IPI. Note that the
* number of CPUs might be zero due to concurrent changes to the
* provided mask.
*/
if (nr_cpus == 1)
send_call_function_single_ipi(last_cpu);
else if (likely(nr_cpus > 1))
arch_send_call_function_ipi_mask(cfd->cpumask_ipi);
cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
}
/* Send a message to all CPUs in the map */
cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->ping, this_cpu,
CFD_SEQ_NOCPU, CFD_SEQ_PING);
arch_send_call_function_ipi_mask(cfd->cpumask_ipi);
cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu,
CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
if (run_local && (!cond_func || cond_func(this_cpu, info))) {
unsigned long flags;
if (wait) {
local_irq_save(flags);
func(info);
local_irq_restore(flags);
}
if (run_remote && wait) {
for_each_cpu(cpu, cfd->cpumask) {
call_single_data_t *csd;
@ -948,12 +970,14 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
}
/**
* smp_call_function_many(): Run a function on a set of other CPUs.
* smp_call_function_many(): Run a function on a set of CPUs.
* @mask: The set of cpus to run on (only runs on online subset).
* @func: The function to run. This must be fast and non-blocking.
* @info: An arbitrary pointer to pass to the function.
* @wait: If true, wait (atomically) until function has completed
* on other CPUs.
* @flags: Bitmask that controls the operation. If %SCF_WAIT is set, wait
* (atomically) until function has completed on other CPUs. If
* %SCF_RUN_LOCAL is set, the function will also be run locally
* if the local CPU is set in the @cpumask.
*
* If @wait is true, then returns once @func has returned.
*
@ -964,7 +988,7 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
void smp_call_function_many(const struct cpumask *mask,
smp_call_func_t func, void *info, bool wait)
{
smp_call_function_many_cond(mask, func, info, wait, NULL);
smp_call_function_many_cond(mask, func, info, wait * SCF_WAIT, NULL);
}
EXPORT_SYMBOL(smp_call_function_many);
@ -1075,56 +1099,6 @@ void __init smp_init(void)
smp_cpus_done(setup_max_cpus);
}
/*
* Call a function on all processors. May be used during early boot while
* early_boot_irqs_disabled is set. Use local_irq_save/restore() instead
* of local_irq_disable/enable().
*/
void on_each_cpu(smp_call_func_t func, void *info, int wait)
{
unsigned long flags;
preempt_disable();
smp_call_function(func, info, wait);
local_irq_save(flags);
func(info);
local_irq_restore(flags);
preempt_enable();
}
EXPORT_SYMBOL(on_each_cpu);
/**
* on_each_cpu_mask(): Run a function on processors specified by
* cpumask, which may include the local processor.
* @mask: The set of cpus to run on (only runs on online subset).
* @func: The function to run. This must be fast and non-blocking.
* @info: An arbitrary pointer to pass to the function.
* @wait: If true, wait (atomically) until function has completed
* on other CPUs.
*
* If @wait is true, then returns once @func has returned.
*
* You must not call this function with disabled interrupts or from a
* hardware interrupt handler or from a bottom half handler. The
* exception is that it may be used during early boot while
* early_boot_irqs_disabled is set.
*/
void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
void *info, bool wait)
{
int cpu = get_cpu();
smp_call_function_many(mask, func, info, wait);
if (cpumask_test_cpu(cpu, mask)) {
unsigned long flags;
local_irq_save(flags);
func(info);
local_irq_restore(flags);
}
put_cpu();
}
EXPORT_SYMBOL(on_each_cpu_mask);
/*
* on_each_cpu_cond(): Call a function on each processor for which
* the supplied function cond_func returns true, optionally waiting
@ -1150,27 +1124,17 @@ EXPORT_SYMBOL(on_each_cpu_mask);
void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
void *info, bool wait, const struct cpumask *mask)
{
int cpu = get_cpu();
unsigned int scf_flags = SCF_RUN_LOCAL;
smp_call_function_many_cond(mask, func, info, wait, cond_func);
if (cpumask_test_cpu(cpu, mask) && cond_func(cpu, info)) {
unsigned long flags;
if (wait)
scf_flags |= SCF_WAIT;
local_irq_save(flags);
func(info);
local_irq_restore(flags);
}
put_cpu();
preempt_disable();
smp_call_function_many_cond(mask, func, info, scf_flags, cond_func);
preempt_enable();
}
EXPORT_SYMBOL(on_each_cpu_cond_mask);
void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func,
void *info, bool wait)
{
on_each_cpu_cond_mask(cond_func, func, info, wait, cpu_online_mask);
}
EXPORT_SYMBOL(on_each_cpu_cond);
static void do_nothing(void *unused)
{
}

38
kernel/up.c
View File

@ -36,35 +36,6 @@ int smp_call_function_single_async(int cpu, call_single_data_t *csd)
}
EXPORT_SYMBOL(smp_call_function_single_async);
void on_each_cpu(smp_call_func_t func, void *info, int wait)
{
unsigned long flags;
local_irq_save(flags);
func(info);
local_irq_restore(flags);
}
EXPORT_SYMBOL(on_each_cpu);
/*
* Note we still need to test the mask even for UP
* because we actually can get an empty mask from
* code that on SMP might call us without the local
* CPU in the mask.
*/
void on_each_cpu_mask(const struct cpumask *mask,
smp_call_func_t func, void *info, bool wait)
{
unsigned long flags;
if (cpumask_test_cpu(0, mask)) {
local_irq_save(flags);
func(info);
local_irq_restore(flags);
}
}
EXPORT_SYMBOL(on_each_cpu_mask);
/*
* Preemption is disabled here to make sure the cond_func is called under the
* same condtions in UP and SMP.
@ -75,7 +46,7 @@ void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
unsigned long flags;
preempt_disable();
if (cond_func(0, info)) {
if ((!cond_func || cond_func(0, info)) && cpumask_test_cpu(0, mask)) {
local_irq_save(flags);
func(info);
local_irq_restore(flags);
@ -84,13 +55,6 @@ void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
}
EXPORT_SYMBOL(on_each_cpu_cond_mask);
void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func,
void *info, bool wait)
{
on_each_cpu_cond_mask(cond_func, func, info, wait, NULL);
}
EXPORT_SYMBOL(on_each_cpu_cond);
int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
{
int ret;