Re: [RFC PATCH v8 1/9] Restartable sequences system call

From: Linus Torvalds
Date: Fri Aug 19 2016 - 17:47:57 EST


On Fri, Aug 19, 2016 at 2:19 PM, Paul E. McKenney
<paulmck@xxxxxxxxxxxxxxxxxx> wrote:
> On Fri, Aug 19, 2016 at 01:56:11PM -0700, Andi Kleen wrote:
>>
>> malloc is the primary target I believe. Saves lots of memory to keep
>> caches per CPU rather than per thread.
>
> Agreed, a competent default malloc() in glibc would be a very nice change
> from the current state.

I agree that malloc can be a very good target for something like this,
but it is also something that is quite complicated. A general-purpose
allocator that could be used by glibc and has not just the performance
but the debug stuff etc that people inevitably want is a big project.
And then the people who have special needs end up writing their own
allocators anyway, just because they care about certain layout and
access patterns...

Put another way: I'd really like to see some real numbers and use,
rather than "this can be used for.."

Linus