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authorMel Gorman <mgorman@suse.de>2014-01-21 14:33:16 -0800
committerIngo Molnar <mingo@kernel.org>2014-01-25 09:10:41 +0100
commitec65993443736a5091b68e80ff1734548944a4b8 (patch)
treea2f9e960f8b9113012118de382ffcda741a1feaf
parent2993ae3305ad10b41e0d0bc2662f7754ee8e30fa (diff)
downloadnet-ec65993443736a5091b68e80ff1734548944a4b8.tar.gz
mm, x86: Account for TLB flushes only when debugging
Bisection between 3.11 and 3.12 fingered commit 9824cf97 ("mm: vmstats: tlb flush counters") to cause overhead problems. The counters are undeniably useful but how often do we really need to debug TLB flush related issues? It does not justify taking the penalty everywhere so make it a debugging option. Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Davidlohr Bueso <davidlohr@hp.com> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Alex Shi <alex.shi@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-XzxjntugxuwpxXhcrxqqh53b@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat
-rw-r--r--arch/x86/include/asm/tlbflush.h6
-rw-r--r--arch/x86/kernel/cpu/mtrr/generic.c4
-rw-r--r--arch/x86/mm/tlb.c14
-rw-r--r--include/linux/vm_event_item.h4
-rw-r--r--include/linux/vmstat.h8
-rw-r--r--mm/vmstat.c4
6 files changed, 26 insertions, 14 deletions
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index e6d90babc245c1..04905bfc508b99 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -62,7 +62,7 @@ static inline void __flush_tlb_all(void)
static inline void __flush_tlb_one(unsigned long addr)
{
- count_vm_event(NR_TLB_LOCAL_FLUSH_ONE);
+ count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ONE);
__flush_tlb_single(addr);
}
@@ -93,13 +93,13 @@ static inline void __flush_tlb_one(unsigned long addr)
*/
static inline void __flush_tlb_up(void)
{
- count_vm_event(NR_TLB_LOCAL_FLUSH_ALL);
+ count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
__flush_tlb();
}
static inline void flush_tlb_all(void)
{
- count_vm_event(NR_TLB_LOCAL_FLUSH_ALL);
+ count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
__flush_tlb_all();
}
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index ce2d0a2c3e4ff5..0e25a1bc5ab5cf 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -683,7 +683,7 @@ static void prepare_set(void) __acquires(set_atomicity_lock)
}
/* Flush all TLBs via a mov %cr3, %reg; mov %reg, %cr3 */
- count_vm_event(NR_TLB_LOCAL_FLUSH_ALL);
+ count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
__flush_tlb();
/* Save MTRR state */
@@ -697,7 +697,7 @@ static void prepare_set(void) __acquires(set_atomicity_lock)
static void post_set(void) __releases(set_atomicity_lock)
{
/* Flush TLBs (no need to flush caches - they are disabled) */
- count_vm_event(NR_TLB_LOCAL_FLUSH_ALL);
+ count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
__flush_tlb();
/* Intel (P6) standard MTRRs */
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index ae699b3bbac84a..05446c1cccfe02 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -103,7 +103,7 @@ static void flush_tlb_func(void *info)
if (f->flush_mm != this_cpu_read(cpu_tlbstate.active_mm))
return;
- count_vm_event(NR_TLB_REMOTE_FLUSH_RECEIVED);
+ count_vm_tlb_event(NR_TLB_REMOTE_FLUSH_RECEIVED);
if (this_cpu_read(cpu_tlbstate.state) == TLBSTATE_OK) {
if (f->flush_end == TLB_FLUSH_ALL)
local_flush_tlb();
@@ -131,7 +131,7 @@ void native_flush_tlb_others(const struct cpumask *cpumask,
info.flush_start = start;
info.flush_end = end;
- count_vm_event(NR_TLB_REMOTE_FLUSH);
+ count_vm_tlb_event(NR_TLB_REMOTE_FLUSH);
if (is_uv_system()) {
unsigned int cpu;
@@ -151,7 +151,7 @@ void flush_tlb_current_task(void)
preempt_disable();
- count_vm_event(NR_TLB_LOCAL_FLUSH_ALL);
+ count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
local_flush_tlb();
if (cpumask_any_but(mm_cpumask(mm), smp_processor_id()) < nr_cpu_ids)
flush_tlb_others(mm_cpumask(mm), mm, 0UL, TLB_FLUSH_ALL);
@@ -215,7 +215,7 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
/* tlb_flushall_shift is on balance point, details in commit log */
if ((end - start) >> PAGE_SHIFT > act_entries >> tlb_flushall_shift) {
- count_vm_event(NR_TLB_LOCAL_FLUSH_ALL);
+ count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
local_flush_tlb();
} else {
if (has_large_page(mm, start, end)) {
@@ -224,7 +224,7 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
}
/* flush range by one by one 'invlpg' */
for (addr = start; addr < end; addr += PAGE_SIZE) {
- count_vm_event(NR_TLB_LOCAL_FLUSH_ONE);
+ count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ONE);
__flush_tlb_single(addr);
}
@@ -262,7 +262,7 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long start)
static void do_flush_tlb_all(void *info)
{
- count_vm_event(NR_TLB_REMOTE_FLUSH_RECEIVED);
+ count_vm_tlb_event(NR_TLB_REMOTE_FLUSH_RECEIVED);
__flush_tlb_all();
if (this_cpu_read(cpu_tlbstate.state) == TLBSTATE_LAZY)
leave_mm(smp_processor_id());
@@ -270,7 +270,7 @@ static void do_flush_tlb_all(void *info)
void flush_tlb_all(void)
{
- count_vm_event(NR_TLB_REMOTE_FLUSH);
+ count_vm_tlb_event(NR_TLB_REMOTE_FLUSH);
on_each_cpu(do_flush_tlb_all, NULL, 1);
}
diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index c557c6d096def9..3a712e2e7d762f 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -71,12 +71,14 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
THP_ZERO_PAGE_ALLOC,
THP_ZERO_PAGE_ALLOC_FAILED,
#endif
+#ifdef CONFIG_DEBUG_TLBFLUSH
#ifdef CONFIG_SMP
NR_TLB_REMOTE_FLUSH, /* cpu tried to flush others' tlbs */
NR_TLB_REMOTE_FLUSH_RECEIVED,/* cpu received ipi for flush */
-#endif
+#endif /* CONFIG_SMP */
NR_TLB_LOCAL_FLUSH_ALL,
NR_TLB_LOCAL_FLUSH_ONE,
+#endif /* CONFIG_DEBUG_TLBFLUSH */
NR_VM_EVENT_ITEMS
};
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index e4b948080d20e7..80ebba9c2e87ee 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -83,6 +83,14 @@ static inline void vm_events_fold_cpu(int cpu)
#define count_vm_numa_events(x, y) do { (void)(y); } while (0)
#endif /* CONFIG_NUMA_BALANCING */
+#ifdef CONFIG_DEBUG_TLBFLUSH
+#define count_vm_tlb_event(x) count_vm_event(x)
+#define count_vm_tlb_events(x, y) count_vm_events(x, y)
+#else
+#define count_vm_tlb_event(x) do {} while (0)
+#define count_vm_tlb_events(x, y) do { (void)(y); } while (0)
+#endif
+
#define __count_zone_vm_events(item, zone, delta) \
__count_vm_events(item##_NORMAL - ZONE_NORMAL + \
zone_idx(zone), delta)
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 72496140ac0843..def5dd2fbe6124 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -851,12 +851,14 @@ const char * const vmstat_text[] = {
"thp_zero_page_alloc",
"thp_zero_page_alloc_failed",
#endif
+#ifdef CONFIG_DEBUG_TLBFLUSH
#ifdef CONFIG_SMP
"nr_tlb_remote_flush",
"nr_tlb_remote_flush_received",
-#endif
+#endif /* CONFIG_SMP */
"nr_tlb_local_flush_all",
"nr_tlb_local_flush_one",
+#endif /* CONFIG_DEBUG_TLBFLUSH */
#endif /* CONFIG_VM_EVENTS_COUNTERS */
};
generated by cgit 1.2.3-korg (git 2.43.0) at 2025-12-06 19:10:06 +0000