Messages in this thread | | | Date | Fri, 7 Nov 2008 18:08:29 -0500 | From | Mathieu Desnoyers <> | Subject | Re: [PATCH-ugly] kmemtrace: casting a gfp_t requires __force |
| |
* Eduard - Gabriel Munteanu (eduard.munteanu@linux360.ro) wrote: > On Fri, Nov 07, 2008 at 10:20:29PM +0300, Alexey Dobriyan wrote: > > On Fri, Nov 07, 2008 at 10:58:41AM -0800, Harvey Harrison wrote: > > > --- a/include/linux/kmemtrace.h > > > +++ b/include/linux/kmemtrace.h > > > @@ -34,7 +34,7 @@ static inline void kmemtrace_mark_alloc_node(enum kmemtrace_type_id type_id, > > > "bytes_req %lu bytes_alloc %lu gfp_flags %lu node %d", > > > type_id, call_site, (unsigned long) ptr, > > > (unsigned long) bytes_req, (unsigned long) bytes_alloc, > > > - (unsigned long) gfp_flags, node); > > > + (__force unsigned long)gfp_flags, node); > > > > gfp_t is "unsigned int" actually. These casts are bogus. > > > > Subject: How do I printk <type> correctly? > > > > If variable is of Type use printk format specifier. > > --------------------------------------------------------- > > int %d or %x > > unsigned int %u or %x > > long %ld ot %lx > > unsigned long %lu or %lx > > long long %lld or %llx > > unsigned long long %llu or %llx > > size_t %zu or %zx > > ssize_t %zd or %zx > > > > Raw pointer value SHOULD be printed with %p. > > > > u64 SHOULD be printed with %llu/%llx, (unsigned long long): > > > > printk("%llu", (unsigned long long)u64_var); > > > > s64 SHOULD be printed with %lld/%llx, (long long): > > > > printk("%lld", (long long)s64_var); > > > > If type is dependent on config option (sector_t), use format specifier > > of biggest type and explicitly cast to it. > > > > Reminder: sizeof() result is of type size_t. > > > > Thank you for your cooperation. > > Hi, > > Actually, "%zu" was the first thing that crossed my mind too. But we > don't want to carry such types into the probe callbacks.
quote : > It's a lot > easier to see which u* an unsigned long fits into than it is for > size_t.
why would you need to limit yourself to u8, u16, u32, u64 ?
sizeof(size_t) tells you for sure what the size of size_t is. You can even export it to a trace header so that size is know when the trace is analyzed, neat eh ? :)
Why would you ever want to create a macro to make typing more obscure and to take considerably more space on architectures where a u64 is not required ?
Mathieu
> So we take care of this inside a wrapper; the sooner, the better. > > Also take into account that debugging code usually casts pointers to > unsigned long. This can easily be seen by looking at _RET_IP_ definition > or SLAB code. I think there's a very good reason to do so, since it adds > opacity to something that's not supposed to be used as a pointer. > > > Cheers, > Eduard >
-- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
| |