Re: [patch 00/13] Syslets, "Threadlets", generic AIO support, v3

[Ingo Molnar <mingo@elte.hu>]

* Davide Libenzi <davidel@xmailserver.org> wrote:

> My point is, the syslet infrastructure is expensive for the kernel in 
> terms of compat, [...]

it is not. Today i've implemented 64-bit syslets on x86_64 and 
32-bit-on-64-bit compat syslets. Both the 64-bit and the 32-bit syslet 
(and threadlet) binaries work just fine on a 64-bit kernel, and they 
share 99% of the infrastructure. There's only a single #ifdef 
CONFIG_COMPAT in kernel/async.c:

#ifdef CONFIG_COMPAT

asmlinkage struct syslet_uatom __user *
compat_sys_async_exec(struct syslet_uatom __user *uatom,
                      struct async_head_user __user *ahu)
{
        return __sys_async_exec(uatom, ahu, &compat_sys_call_table,
                                compat_NR_syscalls);
}

#endif

Even mixed-mode syslets should work (although i havent specifically 
tested them), where the head switches between 64-bit and 32-bit mode and 
submits syslets from both 64-bit and from 32-bit mode, and at the same 
time there might be both 64-bit and 32-bit syslets 'in flight'.

But i'm happy to change the syslet API in any sane way, and did so based 
on feedback from Jens who is actually using them.

	Ingo