Messages in this thread | | | Subject | Re: [Patch 2/3] fast VMA recycling | From | Arjan van de Ven <> | Date | Thu, 23 Feb 2006 10:48:50 +0100 |
| |
On Thu, 2006-02-23 at 10:42 +0100, Andi Kleen wrote: > On Thursday 23 February 2006 10:30, Arjan van de Ven wrote: > > This patch adds a per task-struct cache of a free vma. > > > > In normal operation, it is a really common action during userspace mmap > > or malloc to first allocate a vma, and then find out that it can be merged, > > and thus free it again. In fact this is the case roughly 95% of the time. > > > > In addition, this patch allows code to "prepopulate" the cache, and > > this is done as example for the x86_64 mmap codepath. The advantage of this > > prepopulation is that the memory allocation (which is a sleeping operation > > due to the GFP_KERNEL flag, potentially causing either a direct sleep or a > > voluntary preempt sleep) will happen before the mmap_sem is taken, and thus > > reduces lock hold time (and thus the contention potential) > > The slab fast path doesn't sleep.
it does via might_sleep()
> Numbers numbers numbers. What workload? How much did it help?
see post 0/3
3% on a threaded allocation benchmark (which resembles a webserver with cgis apparently) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |