Re: [PATCH v2 12/54] accel/tcg: Remove IntervalTree entries in tlb_flush_range_locked

[Pierrick Bouvier <pierrick.bouvier@linaro.org>]

On 11/14/24 08:00, Richard Henderson wrote:
> Flush a masked range of pages from the IntervalTree cache.
> When the mask is not used there is a redundant comparison,
> but that is better than duplicating code at this point.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   accel/tcg/cputlb.c | 25 +++++++++++++++++++++++++
>   1 file changed, 25 insertions(+)
> 
> diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
> index d532d69083..e2c855f147 100644
> --- a/accel/tcg/cputlb.c
> +++ b/accel/tcg/cputlb.c
> @@ -311,6 +311,13 @@ static CPUTLBEntryTree *tlbtree_lookup_range(CPUTLBDesc *desc, vaddr s, vaddr l)
>       return i ? container_of(i, CPUTLBEntryTree, itree) : NULL;
>   }
>   
> +static CPUTLBEntryTree *tlbtree_lookup_range_next(CPUTLBEntryTree *prev,
> +                                                  vaddr s, vaddr l)
> +{
> +    IntervalTreeNode *i = interval_tree_iter_next(&prev->itree, s, l);
> +    return i ? container_of(i, CPUTLBEntryTree, itree) : NULL;
> +}
> +
>   static CPUTLBEntryTree *tlbtree_lookup_addr(CPUTLBDesc *desc, vaddr addr)
>   {
>       return tlbtree_lookup_range(desc, addr, addr);
> @@ -739,6 +746,8 @@ static void tlb_flush_range_locked(CPUState *cpu, int midx,
>       CPUTLBDesc *d = &cpu->neg.tlb.d[midx];
>       CPUTLBDescFast *f = &cpu->neg.tlb.f[midx];
>       vaddr mask = MAKE_64BIT_MASK(0, bits);
> +    CPUTLBEntryTree *node;
> +    vaddr addr_mask, last_mask, last_imask;
>   
>       /*
>        * Check if we need to flush due to large pages.
> @@ -759,6 +768,22 @@ static void tlb_flush_range_locked(CPUState *cpu, int midx,
>           vaddr page = addr + i;
>           tlb_flush_vtlb_page_mask_locked(cpu, midx, page, mask);
>       }
> +
> +    addr_mask = addr & mask;
> +    last_mask = addr_mask + len - 1;
> +    last_imask = last_mask | ~mask;
> +    node = tlbtree_lookup_range(d, addr_mask, last_imask);
> +    while (node) {
> +        CPUTLBEntryTree *next =
> +            tlbtree_lookup_range_next(node, addr_mask, last_imask);
> +        vaddr page_mask = node->itree.start & mask;
> +
> +        if (page_mask >= addr_mask && page_mask < last_mask) {
> +            interval_tree_remove(&node->itree, &d->iroot);
> +            g_free(node);
> +        }
> +        node = next;
> +    }
>   }
>   
>   typedef struct {

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