Use EG(vm_stack_page_size).

[twose]

6780c74

@dstogov
I am confused when I read the source code, even if zend_vm_stack_init does not provide parameters to set it, we can write our own init function, but when zend_vm_stack_extend and size > EG(vm_stack_page_size), it still use ZEND_VM_STACK_PAGE_SIZE (256k?), if it's a little big when page_size is 4k or 8k for a coroutine?
emmm... and I do hope that you can provide more powerful APIs for coroutine...
Thanks!

[dstogov]

May be I misunderstood this without the context, but I think the patch is wrong.
I assume, this is for swoole coroutines (or something like this)?

1. Don't use zend_vm_stack_init() for coroutine stack creation (use your own function).
2. When you switch stack, you also should change EG(vm_stack_page_size), and then zend_vm_stack_extend() will use it out of the box.

[twose]

Sorry, I was confused last night and I thought wrong for something, thank you for your prompt answer.
You are right, I know that I should use my own function, I just noticed that we have EG(vm_stack_page_size) in PHP73, and then I replace ZEND_VM_STACK_PAGE_SIZE to EG(vm_stack_page_size).
In ZendVM, they are no difference, but when we can change it, it's more in line with its significance?
Then whether ZEND_VM_STACK_PAGE_ALIGNED_SIZE should use EG(vm_stack_page_size)?
when I use:

<?php
$params = '';
for ($n = 0; $n < 256; $n++) {
    $params .= "\$p{$n} = null;\n";
}
$gen = <<<PHP
<?php
go(function () {
{$params}
});
PHP;
file_put_contents(__DIR__ . '/extend.php', $gen);

In coroutine EG(vm_stack_page_size) = 8192, 256 zval + some other necessary memory are bigger than it (actually 8272), I expect the next new page size is 16384, but I got 262144. Maybe this is not a problem? but I just want to know, thanks.

[dstogov]

you are right. This has to be fixed. I'll think, what to do.

[dstogov]

Please check if this patch works for you
https://gist.github.com/dstogov/cadc9c28f42483b9d44e427321f54176
Actually, your patch was right too.

[twose]

@dstogov Yes! This is what I want! Thanks! your ALIGNED macro is better for using.

[twose]

😵, tab and space mixed in some places, maybe petk can slove these... it looks good now.

[dstogov]

I've merged the patch into master and PHP-7.3

[twose]

👍OK, thank you very much!

[twose]

@dstogov
is it necessary to add an API to set php_stack_page_size in swoole? In swoole, the default page size is 8K, In some cases, if small stack page size will lead to stack extend frequently?
Need your valuable advice, thanks!

[dstogov]

I would add debug counters or logging into zend_vm_stack_extend(), then run few apps and made decision based on collected data.

[twose]

Thanks, I will have a try too.