[PATCH v2 54/54] accel/tcg: Return CPUTLBEntryTree from tlb_set_page_full

Richard Henderson posted 54 patches 1 week, 2 days ago
[PATCH v2 54/54] accel/tcg: Return CPUTLBEntryTree from tlb_set_page_full
Posted by Richard Henderson 1 week, 2 days ago
Avoid a lookup to find the node that we have just inserted.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/cputlb.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index 20af48c6c5..6d316e8767 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -1037,8 +1037,8 @@ static inline void tlb_set_compare(CPUTLBEntryFull *full, CPUTLBEntry *ent,
  * Called from TCG-generated code, which is under an RCU read-side
  * critical section.
  */
-static void tlb_set_page_full(CPUState *cpu, int mmu_idx,
-                              vaddr addr, CPUTLBEntryFull *full)
+static CPUTLBEntryTree *tlb_set_page_full(CPUState *cpu, int mmu_idx,
+                                          vaddr addr, CPUTLBEntryFull *full)
 {
     CPUTLB *tlb = &cpu->neg.tlb;
     CPUTLBDesc *desc = &tlb->d[mmu_idx];
@@ -1187,6 +1187,8 @@ static void tlb_set_page_full(CPUState *cpu, int mmu_idx,
     copy_tlb_helper_locked(te, &node->copy);
     desc->n_used_entries++;
     qemu_spin_unlock(&tlb->c.lock);
+
+    return node;
 }
 
 static inline void cpu_unaligned_access(CPUState *cpu, vaddr addr,
@@ -1266,18 +1268,14 @@ static bool tlb_lookup(CPUState *cpu, TLBLookupOutput *o,
         tcg_debug_assert(probe);
         return false;
     }
-    tlb_set_page_full(cpu, i->mmu_idx, addr, &o->full);
+    node = tlb_set_page_full(cpu, i->mmu_idx, addr, &o->full);
     o->did_tlb_fill = true;
 
     if (access_type == MMU_INST_FETCH) {
-        node = tlbtree_lookup_addr(desc, addr);
-        tcg_debug_assert(node);
         goto found_code;
     }
 
-    entry = tlbfast_entry(fast, addr);
-    cmp = tlb_read_idx(entry, access_type);
-    node = entry->tree;
+    cmp = tlb_read_idx(&node->copy, access_type);
     /*
      * With PAGE_WRITE_INV, we set TLB_INVALID_MASK immediately,
      * to force the next access through tlb_fill_align.  We've just
-- 
2.43.0
Re: [PATCH v2 54/54] accel/tcg: Return CPUTLBEntryTree from tlb_set_page_full
Posted by Pierrick Bouvier 1 week, 1 day ago
On 11/14/24 08:01, Richard Henderson wrote:
> Avoid a lookup to find the node that we have just inserted.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   accel/tcg/cputlb.c | 14 ++++++--------
>   1 file changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
> index 20af48c6c5..6d316e8767 100644
> --- a/accel/tcg/cputlb.c
> +++ b/accel/tcg/cputlb.c
> @@ -1037,8 +1037,8 @@ static inline void tlb_set_compare(CPUTLBEntryFull *full, CPUTLBEntry *ent,
>    * Called from TCG-generated code, which is under an RCU read-side
>    * critical section.
>    */
> -static void tlb_set_page_full(CPUState *cpu, int mmu_idx,
> -                              vaddr addr, CPUTLBEntryFull *full)
> +static CPUTLBEntryTree *tlb_set_page_full(CPUState *cpu, int mmu_idx,
> +                                          vaddr addr, CPUTLBEntryFull *full)
>   {
>       CPUTLB *tlb = &cpu->neg.tlb;
>       CPUTLBDesc *desc = &tlb->d[mmu_idx];
> @@ -1187,6 +1187,8 @@ static void tlb_set_page_full(CPUState *cpu, int mmu_idx,
>       copy_tlb_helper_locked(te, &node->copy);
>       desc->n_used_entries++;
>       qemu_spin_unlock(&tlb->c.lock);
> +
> +    return node;
>   }
>   
>   static inline void cpu_unaligned_access(CPUState *cpu, vaddr addr,
> @@ -1266,18 +1268,14 @@ static bool tlb_lookup(CPUState *cpu, TLBLookupOutput *o,
>           tcg_debug_assert(probe);
>           return false;
>       }
> -    tlb_set_page_full(cpu, i->mmu_idx, addr, &o->full);
> +    node = tlb_set_page_full(cpu, i->mmu_idx, addr, &o->full);
>       o->did_tlb_fill = true;
>   
>       if (access_type == MMU_INST_FETCH) {
> -        node = tlbtree_lookup_addr(desc, addr);
> -        tcg_debug_assert(node);
>           goto found_code;
>       }
>   
> -    entry = tlbfast_entry(fast, addr);
> -    cmp = tlb_read_idx(entry, access_type);
> -    node = entry->tree;
> +    cmp = tlb_read_idx(&node->copy, access_type);
>       /*
>        * With PAGE_WRITE_INV, we set TLB_INVALID_MASK immediately,
>        * to force the next access through tlb_fill_align.  We've just

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>