Re: would a mutex_wait be useful?

[christos%astron.com@localhost (Christos Zoulas)]

In article <20081104200024.AAB3863B10C%mail.netbsd.org@localhost>,
Mindaugas Rasiukevicius  <rmind%NetBSD.org@localhost> wrote:
>Mindaugas Rasiukevicius <rmind%NetBSD.org@localhost> wrote:
>> Matt Thomas <matt%3am-software.com@localhost> wrote:
>> > > Where/when do you need interruptible mutex?
>> > 
>> > I was replacing code in arm32/mem.c with a home grown lock with  
>> > mutex_enter.
>> > Relatively easy to do except it no longer does PCATCH.
>> 
>> I agree with Antti that code asks for condvar(9), at least.
>
>Actually, taken a look at arm32/mem.c again, no need for condvar(9). If there
>is a contention on mm_lock, hashed locks would help. Is it worth?
>
>You probably was intended to set the D_MPSAFE flag for mem_cdevsw. Note that
>this wont be atomic then:
>
>if (zeropage == NULL) {
>       zeropage = (void *)
>           malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
>       memset(zeropage, 0, PAGE_SIZE);
>}
>

if (zeropage == NULL)
        zeropage = malloc(PAGE_SIZE, M_TEMP, M_WAITOK|M_ZERO);

Not a good reason :-)

christos