Re: [GIT PULL v2] Early boot SLAB for 2.6.31

From: Christoph Lameter
Date: Thu Jun 11 2009 - 09:59:45 EST


On Thu, 11 Jun 2009, Pekka J Enberg wrote:

> setup_nr_cpu_ids();
> smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
>
> + build_all_zonelists();
> + page_alloc_init();
> +
> + printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
> + parse_early_param();
> + parse_args("Booting kernel", static_command_line, __start___param,
> + __stop___param - __start___param,
> + &unknown_bootoption);
> + /*
> + * These use large bootmem allocations and must precede
> + * kmem_cache_init()
> + */
> + pidhash_init();
> + vfs_caches_init_early();
> + /*
> + * Set up kernel memory allocators
> + */
> + mem_init();
> + kmem_cache_init();
> + vmalloc_init();

Good they are all together. Maybe we can come up with an mm_init()?

> @@ -603,7 +616,6 @@ asmlinkage void __init start_kernel(void)
> /* init some links before init_ISA_irqs() */
> early_irq_init();
> init_IRQ();
> - pidhash_init();
> init_timers();
> hrtimers_init();
> softirq_init();
> @@ -645,14 +657,10 @@ asmlinkage void __init start_kernel(void)
> initrd_start = 0;
> }
> #endif
> - vmalloc_init();
> - vfs_caches_init_early();
> cpuset_init_early();
> page_cgroup_init();
> - mem_init();
> enable_debug_pagealloc();
> cpu_hotplug_init();
> - kmem_cache_init();
> kmemtrace_init();
> debug_objects_mem_init();
> idr_init_cache();

Therefore potential breakage is in cpusets, hotplug and control groups.
Have any of these been tested with these patches? NUMA?

> diff --git a/mm/slub.c b/mm/slub.c
> index 5e805a6..c1815a6 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -2557,13 +2557,16 @@ static struct kmem_cache *create_kmalloc_cache(struct kmem_cache *s,
> if (gfp_flags & SLUB_DMA)
> flags = SLAB_CACHE_DMA;
>
> - down_write(&slub_lock);
> + /*
> + * This function is called with IRQs disabled during early-boot on
> + * single CPU so there's no need to take slub_lock here.
> + */
> if (!kmem_cache_open(s, gfp_flags, name, size, ARCH_KMALLOC_MINALIGN,

This function is also called later when kmalloc caches are
created on demand.
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