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[Qemu-devel] [RFC 3/6] cputlb: track TLB use rates
From: |
Emilio G. Cota |
Subject: |
[Qemu-devel] [RFC 3/6] cputlb: track TLB use rates |
Date: |
Sat, 6 Oct 2018 17:45:05 -0400 |
This paves the way for implementing a dynamically-sized softmmu.
Signed-off-by: Emilio G. Cota <address@hidden>
---
include/exec/cpu-defs.h | 1 +
accel/tcg/cputlb.c | 17 ++++++++++++++---
2 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/include/exec/cpu-defs.h b/include/exec/cpu-defs.h
index fa95a4257e..af9fe04b0b 100644
--- a/include/exec/cpu-defs.h
+++ b/include/exec/cpu-defs.h
@@ -144,6 +144,7 @@ typedef struct CPUIOTLBEntry {
typedef struct CPUTLBDesc {
size_t size;
size_t mask; /* (.size - 1) << CPU_TLB_ENTRY_BITS for TLB fast path */
+ size_t used;
} CPUTLBDesc;
#define CPU_COMMON_TLB \
diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index 0e2c149d6b..ed19ac0e40 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -84,6 +84,7 @@ void tlb_init(CPUState *cpu)
desc->size = CPU_TLB_SIZE;
desc->mask = (desc->size - 1) << CPU_TLB_ENTRY_BITS;
+ desc->used = 0;
env->tlb_table[i] = g_new(CPUTLBEntry, desc->size);
env->iotlb[i] = g_new0(CPUIOTLBEntry, desc->size);
}
@@ -152,6 +153,7 @@ static void tlb_flush_nocheck(CPUState *cpu)
for (i = 0; i < NB_MMU_MODES; i++) {
memset(env->tlb_table[i], -1,
env->tlb_desc[i].size * sizeof(CPUTLBEntry));
+ env->tlb_desc[i].used = 0;
}
memset(env->tlb_v_table, -1, sizeof(env->tlb_v_table));
qemu_spin_unlock(&env->tlb_lock);
@@ -216,6 +218,7 @@ static void tlb_flush_by_mmuidx_async_work(CPUState *cpu,
run_on_cpu_data data)
memset(env->tlb_table[mmu_idx], -1,
env->tlb_desc[mmu_idx].size * sizeof(CPUTLBEntry));
memset(env->tlb_v_table[mmu_idx], -1, sizeof(env->tlb_v_table[0]));
+ env->tlb_desc[mmu_idx].used = 0;
}
}
qemu_spin_unlock(&env->tlb_lock);
@@ -276,12 +279,14 @@ 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 */
@@ -321,7 +326,9 @@ static void tlb_flush_page_async_work(CPUState *cpu,
run_on_cpu_data data)
for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
int i = (addr >> TARGET_PAGE_BITS) & (env->tlb_desc[mmu_idx].size - 1);
- tlb_flush_entry_locked(&env->tlb_table[mmu_idx][i], addr);
+ if (tlb_flush_entry_locked(&env->tlb_table[mmu_idx][i], addr)) {
+ env->tlb_desc[mmu_idx].used--;
+ }
tlb_flush_vtlb_page_locked(env, mmu_idx, addr);
}
qemu_spin_unlock(&env->tlb_lock);
@@ -365,7 +372,9 @@ static void tlb_flush_page_by_mmuidx_async_work(CPUState
*cpu,
page = (addr >> TARGET_PAGE_BITS) & (env->tlb_desc[mmu_idx].size - 1);
if (test_bit(mmu_idx, &mmu_idx_bitmap)) {
- tlb_flush_entry_locked(&env->tlb_table[mmu_idx][page], addr);
+ if (tlb_flush_entry_locked(&env->tlb_table[mmu_idx][page], addr)) {
+ env->tlb_desc[mmu_idx].used--;
+ }
tlb_flush_vtlb_page_locked(env, mmu_idx, addr);
}
}
@@ -702,6 +711,7 @@ 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].used--;
}
/* refill the tlb */
@@ -753,6 +763,7 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong
vaddr,
}
copy_tlb_helper_locked(te, &tn);
+ env->tlb_desc[mmu_idx].used++;
qemu_spin_unlock(&env->tlb_lock);
}
--
2.17.1