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[Qemu-devel] [RFC v3 4/5] cputlb: track TLB use rate
From: |
Emilio G. Cota |
Subject: |
[Qemu-devel] [RFC v3 4/5] cputlb: track TLB use rate |
Date: |
Tue, 9 Oct 2018 13:51:28 -0400 |
This paves the way for implementing a dynamically-sized softmmu.
Reviewed-by: Alex Bennée <address@hidden>
Signed-off-by: Emilio G. Cota <address@hidden>
---
include/exec/cpu-defs.h | 5 +++++
accel/tcg/cputlb.c | 17 ++++++++++++++---
2 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/include/exec/cpu-defs.h b/include/exec/cpu-defs.h
index 87cd015f60..56f1887c7f 100644
--- a/include/exec/cpu-defs.h
+++ b/include/exec/cpu-defs.h
@@ -141,10 +141,15 @@ typedef struct CPUIOTLBEntry {
MemTxAttrs attrs;
} CPUIOTLBEntry;
+typedef struct CPUTLBDesc {
+ size_t n_used_entries;
+} CPUTLBDesc;
+
#define CPU_COMMON_TLB \
/* The meaning of the MMU modes is defined in the target code. */ \
/* tlb_lock serializes updates to tlb_mask, tlb_table and tlb_v_table */ \
QemuSpin tlb_lock; \
+ CPUTLBDesc tlb_desc[NB_MMU_MODES]; \
/* tlb_mask[i] contains (n_entries - 1) << CPU_TLB_ENTRY_BITS */ \
uintptr_t tlb_mask[NB_MMU_MODES]; \
CPUTLBEntry *tlb_table[NB_MMU_MODES]; \
diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index 4dc47e603c..11d6060eb0 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -82,6 +82,7 @@ void tlb_init(CPUState *cpu)
for (i = 0; i < NB_MMU_MODES; i++) {
size_t n_entries = CPU_TLB_SIZE;
+ env->tlb_desc[i].n_used_entries = 0;
env->tlb_mask[i] = (n_entries - 1) << CPU_TLB_ENTRY_BITS;
env->tlb_table[i] = g_new(CPUTLBEntry, n_entries);
env->iotlb[i] = g_new0(CPUIOTLBEntry, n_entries);
@@ -150,6 +151,7 @@ static void tlb_flush_nocheck(CPUState *cpu)
qemu_spin_lock(&env->tlb_lock);
for (i = 0; i < NB_MMU_MODES; i++) {
memset(env->tlb_table[i], -1, sizeof_tlb(env, i));
+ env->tlb_desc[i].n_used_entries = 0;
}
memset(env->tlb_v_table, -1, sizeof(env->tlb_v_table));
qemu_spin_unlock(&env->tlb_lock);
@@ -213,6 +215,7 @@ static void tlb_flush_by_mmuidx_async_work(CPUState *cpu,
run_on_cpu_data data)
memset(env->tlb_table[mmu_idx], -1, sizeof_tlb(env, mmu_idx));
memset(env->tlb_v_table[mmu_idx], -1, sizeof(env->tlb_v_table[0]));
+ env->tlb_desc[mmu_idx].n_used_entries = 0;
}
}
qemu_spin_unlock(&env->tlb_lock);
@@ -273,12 +276,14 @@ static inline bool tlb_hit_page_anyprot(CPUTLBEntry
*tlb_entry,
}
/* Called with tlb_lock held */
-static inline void tlb_flush_entry_locked(CPUTLBEntry *tlb_entry,
+static inline bool tlb_flush_entry_locked(CPUTLBEntry *tlb_entry,
target_ulong page)
{
if (tlb_hit_page_anyprot(tlb_entry, page)) {
memset(tlb_entry, -1, sizeof(*tlb_entry));
+ return true;
}
+ return false;
}
/* Called with tlb_lock held */
@@ -316,7 +321,9 @@ static void tlb_flush_page_async_work(CPUState *cpu,
run_on_cpu_data data)
addr &= TARGET_PAGE_MASK;
qemu_spin_lock(&env->tlb_lock);
for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
- tlb_flush_entry_locked(tlb_entry(env, mmu_idx, addr), addr);
+ if (tlb_flush_entry_locked(tlb_entry(env, mmu_idx, addr), addr)) {
+ env->tlb_desc[mmu_idx].n_used_entries--;
+ }
tlb_flush_vtlb_page_locked(env, mmu_idx, addr);
}
qemu_spin_unlock(&env->tlb_lock);
@@ -358,7 +365,9 @@ static void tlb_flush_page_by_mmuidx_async_work(CPUState
*cpu,
qemu_spin_lock(&env->tlb_lock);
for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
if (test_bit(mmu_idx, &mmu_idx_bitmap)) {
- tlb_flush_entry_locked(tlb_entry(env, mmu_idx, addr), addr);
+ if (tlb_flush_entry_locked(tlb_entry(env, mmu_idx, addr), addr)) {
+ env->tlb_desc[mmu_idx].n_used_entries--;
+ }
tlb_flush_vtlb_page_locked(env, mmu_idx, addr);
}
}
@@ -696,6 +705,7 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong
vaddr,
/* Evict the old entry into the victim tlb. */
copy_tlb_helper_locked(tv, te);
env->iotlb_v[mmu_idx][vidx] = env->iotlb[mmu_idx][index];
+ env->tlb_desc[mmu_idx].n_used_entries--;
}
/* refill the tlb */
@@ -747,6 +757,7 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong
vaddr,
}
copy_tlb_helper_locked(te, &tn);
+ env->tlb_desc[mmu_idx].n_used_entries++;
qemu_spin_unlock(&env->tlb_lock);
}
--
2.17.1