[Qemu-devel] Re: [RFC v4] Introduce qemu_madvise()

[Alexander Graf]

Am 14.09.2010 um 18:31 schrieb Blue Swirl <address@hidden>:

> On Mon, Sep 13, 2010 at 9:26 PM, Andreas Färber <address@hidden> wrote:
>> From: Andreas Färber <address@hidden>
>> 
>> vl.c has a Sun-specific hack to supply a prototype for madvise(),
>> but the call site has apparently moved to arch_init.c.
>> 
>> Haiku doesn't implement madvise() in favor of posix_madvise().
>> OpenBSD and Solaris 10 don't implement posix_madvise() but madvise().
>> 
>> Check for madvise() and posix_madvise() in configure and supply 
>> qemu_madvise()
>> as wrapper. Prefer madvise() over posix_madvise() due to flag availability.
>> Convert all callers to use qemu_madvise() and QEMU_MADV_*.
>> 
>> Note that on Solaris the warning is fixed by moving the madvise() prototype,
>> not by qemu_madvise() itself. It will help with future porting though.
>> 
>> v3 -> v4:
>> * Eliminate #ifdefs at qemu_advise() call sites. Requested by Blue Swirl.
>>  This will currently break the check in kvm-all.c by calling madvise() with
>>  a supported flag, which will not fail. Ideas/patches welcome.
> 
> Your original switch with synthetic (1<<0, 1<<1 etc) values for
> QEMU_MADV_* for all hosts (never reusing MADV_* defines).

Ugh. Back to square one? How about

#define QEMU_MADV_INVALID -1

Then you can define unknown balues against that. Should never occur otherwise.


Alex