On Mon, Nov 20 2006, Alan Stern wrote:
> On Mon, 20 Nov 2006, Jens Axboe wrote:
>
> > > > Must we introduce memory allocations in srcu_read_lock()? It makes it
> > > > much harder and nastier for me to use. I'd much prefer a failing
> > > > init_srcu(), seems like a much better API.
> > >
> > > Paul agrees with you that allocation failures in init_srcu() should be
> > > passed back to the caller, and I certainly don't mind doing so.
> > >
> > > However we can't remove the memory allocation in srcu_read_lock(). That
> > > was the point which started this whole thread: the per-cpu allocation
> > > cannot be done statically, and some users of a static SRCU structure can't
> > > easily call init_srcu() early enough.
> > >
> > > Once the allocation succeeds, the overhead in srcu_read_lock() is minimal.
> >
> > It's not about the overhead, it's about a potentially problematic
> > allocation.
>
> I'm not sure what you mean by "problematic allocation". If you
> successfully call init_srcu_struct then the allocation will be taken care
> of. Later calls to srcu_read_lock won't experience any slowdowns or
> problems.
That requires init_srcu_struct() to return the error. If it does that,
I'm fine with it.
> Does this answer your objection? If not, can you explain in more detail
> what other features you would like?
It does, if the allocation failure in init_srcu_struct() is signalled.
--
Jens Axboe
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
