[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 2/5] tcg: reorganize tb_find_physical loop
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [PATCH 2/5] tcg: reorganize tb_find_physical loop |
Date: |
Tue, 22 Mar 2016 14:59:20 +0000 |
User-agent: |
mu4e 0.9.17; emacs 25.0.92.7 |
address@hidden writes:
> From: Paolo Bonzini <address@hidden>
>
> Use a continue statement.
>
> Signed-off-by: Paolo Bonzini <address@hidden>
> [Sergey Fedorov: Fix moving to list head in case of no TB]
> Signed-off-by: Sergey Fedorov <address@hidden>
> ---
> cpu-exec.c | 50 +++++++++++++++++++++++++-------------------------
> 1 file changed, 25 insertions(+), 25 deletions(-)
>
> diff --git a/cpu-exec.c b/cpu-exec.c
> index fd92452f16f6..f90482eff778 100644
> --- a/cpu-exec.c
> +++ b/cpu-exec.c
> @@ -225,37 +225,37 @@ static TranslationBlock *tb_find_physical(CPUState *cpu,
> phys_pc = get_page_addr_code(env, pc);
> phys_page1 = phys_pc & TARGET_PAGE_MASK;
> h = tb_phys_hash_func(phys_pc);
> - ptb1 = &tcg_ctx.tb_ctx.tb_phys_hash[h];
> - for(;;) {
> - tb = *ptb1;
> - if (!tb) {
> - return NULL;
> + for (ptb1 = &tcg_ctx.tb_ctx.tb_phys_hash[h];
> + (tb = *ptb1) != NULL;
> + ptb1 = &tb->phys_hash_next) {
I'm not sure I'm keen on the assignment in the for condition clause. I
appreciate the cleansing of the if !tb return exit though. Could we be
cleaner maybe? Here is my attempt:
static TranslationBlock *tb_find_physical(CPUState *cpu,
target_ulong pc,
target_ulong cs_base,
uint64_t flags)
{
CPUArchState *env = (CPUArchState *)cpu->env_ptr;
TranslationBlock *tb, **tb_hash_head, **ptb1;
unsigned int h;
tb_page_addr_t phys_pc, phys_page1;
/* find translated block using physical mappings */
phys_pc = get_page_addr_code(env, pc);
phys_page1 = phys_pc & TARGET_PAGE_MASK;
h = tb_phys_hash_func(phys_pc);
/* Start at head of the hash entry */
ptb1 = tb_hash_head = &tcg_ctx.tb_ctx.tb_phys_hash[h];
tb = *ptb1;
while (tb) {
if (tb->pc == pc &&
tb->page_addr[0] == phys_page1 &&
tb->cs_base == cs_base &&
tb->flags == flags) {
if (tb->page_addr[1] == -1) {
/* done, we have a match */
break;
} else {
/* check next page if needed */
target_ulong virt_page2 = (pc & TARGET_PAGE_MASK)
+ TARGET_PAGE_SIZE;
tb_page_addr_t phys_page2 = get_page_addr_code(env,
virt_page2);
if (tb->page_addr[1] == phys_page2) {
break;
}
}
}
ptb1 = &tb->phys_hash_next;
tb = *ptb1;
}
if (tb) {
/* Move the TB to the head of the list */
*ptb1 = tb->phys_hash_next;
tb->phys_hash_next = *tb_hash_head;
*tb_hash_head = tb;
}
return tb;
}
FWIW the compiled code is 9 bytes shorter on my machine.
> + if (tb->pc != pc ||
> + tb->page_addr[0] != phys_page1 ||
> + tb->cs_base != cs_base ||
> + tb->flags != flags) {
> + continue;
> }
> - if (tb->pc == pc &&
> - tb->page_addr[0] == phys_page1 &&
> - tb->cs_base == cs_base &&
> - tb->flags == flags) {
> - /* check next page if needed */
> - if (tb->page_addr[1] != -1) {
> - tb_page_addr_t phys_page2;
> -
> - virt_page2 = (pc & TARGET_PAGE_MASK) +
> - TARGET_PAGE_SIZE;
> - phys_page2 = get_page_addr_code(env, virt_page2);
> - if (tb->page_addr[1] == phys_page2) {
> - break;
> - }
> - } else {
> +
> + /* check next page if needed */
> + if (tb->page_addr[1] != -1) {
> + tb_page_addr_t phys_page2;
> +
> + virt_page2 = (pc & TARGET_PAGE_MASK) +
> + TARGET_PAGE_SIZE;
> + phys_page2 = get_page_addr_code(env, virt_page2);
> + if (tb->page_addr[1] == phys_page2) {
> break;
> }
> + } else {
> + break;
> }
> - ptb1 = &tb->phys_hash_next;
> }
>
> - /* Move the TB to the head of the list */
> - *ptb1 = tb->phys_hash_next;
> - tb->phys_hash_next = tcg_ctx.tb_ctx.tb_phys_hash[h];
> - tcg_ctx.tb_ctx.tb_phys_hash[h] = tb;
> + if (tb) {
> + /* Move the TB to the head of the list */
> + *ptb1 = tb->phys_hash_next;
> + tb->phys_hash_next = tcg_ctx.tb_ctx.tb_phys_hash[h];
> + tcg_ctx.tb_ctx.tb_phys_hash[h] = tb;
> + }
> return tb;
> }
--
Alex Bennée
[Qemu-devel] [PATCH 5/5] tcg: move tb_invalidated_flag to CPUState, sergey . fedorov, 2016/03/17
[Qemu-devel] [PATCH 2/5] tcg: reorganize tb_find_physical loop, sergey . fedorov, 2016/03/17
- Re: [Qemu-devel] [PATCH 2/5] tcg: reorganize tb_find_physical loop, Peter Maydell, 2016/03/17
- Re: [Qemu-devel] [PATCH 2/5] tcg: reorganize tb_find_physical loop,
Alex Bennée <=
- Re: [Qemu-devel] [PATCH 2/5] tcg: reorganize tb_find_physical loop, Paolo Bonzini, 2016/03/22
- Re: [Qemu-devel] [PATCH 2/5] tcg: reorganize tb_find_physical loop, Sergey Fedorov, 2016/03/29
- Re: [Qemu-devel] [PATCH 2/5] tcg: reorganize tb_find_physical loop, Paolo Bonzini, 2016/03/29
- Re: [Qemu-devel] [PATCH 2/5] tcg: reorganize tb_find_physical loop, Sergey Fedorov, 2016/03/29
- Re: [Qemu-devel] [PATCH 2/5] tcg: reorganize tb_find_physical loop, Alex Bennée, 2016/03/29
- Re: [Qemu-devel] [PATCH 2/5] tcg: reorganize tb_find_physical loop, Sergey Fedorov, 2016/03/29
[Qemu-devel] [PATCH 1/5] tcg: code_bitmap is not used by user-mode emulation, sergey . fedorov, 2016/03/17