Re: [GIT PULL] scheduler fixes

Nick Piggin
2009-05-25T11:25:21Z

On Mon, May 25, 2009 at 11:47:40AM +0300, Pekka Enberg wrote:
> On Mon, 25 May 2009, Ingo Molnar wrote:
> > Ok, i think this all looks pretty realistic - but there's quite a
> > bit of layering on top of pending changes in the x86 and irq trees.
> > We could do this on top of those topic branches in -tip, and rebase
> > in the merge window. Or delay it to .32.
> >
> > ... plus i think we are _very_ close to being able to remove all of
> > bootmem on x86 (with some compatibility/migration mechanism in
> > place). Which bootmem calls do we have before kmalloc init with
> > Pekka's patch applied? I think it's mostly the page table init code.
> >
> > ( beyond the page allocator internal use - where we could use
> > straight e820 based APIs that clip memory off from the beginning
> > of existing e820 RAM ranges - enriched with NUMA/SRAT locality
> > info. )
>
> OK, here's a version of the patch with Yinghai's rebasing on top of
> tip/master. All in-kernel memory allocators boot cleanly now on my
> configuration (I did not try SLQB but it probably needs fixing). I would
> appreciate if someone gave SLAB+NUMA configuration a try.
>
> Ingo, I don't really want to carry this in slab.git so perhaps you could
> put this and Yinghai's irq init cleanup in a "earlyslab" branch in tip for
> testing?
>
> And oh, Christoph/Matt, can I have your NAK/ACK for this patch?
>
> Pekka
>
> >From f5338db5f1b959cb82ed811037a545e19c7b2b7b Mon Sep 17 00:00:00 2001
> From: Pekka Enberg <penberg@cs.helsinki.fi>
> Date: Mon, 25 May 2009 09:44:39 +0300
> Subject: [PATCH] slab: setup allocators earlier in the boot sequence
>
> This patch makes kmalloc() available earlier in the boot sequence so we can get
> rid of some bootmem allocations. The bulk of the changes are due to
> kmem_cache_init() being called with interrupts disabled which requires some
> changes to allocator boostrap code.
>
> [ yinghai@kernel.org: rebase to tip ]
> Cc: Nick Piggin <npiggin@suse.de>
> Cc: Matt Mackall <mpm@selenic.com>
> Cc: Christoph Lameter <cl@linux-foundation.com>
> Cc: Linus Torvalds <torvals@linux-foundation.org>
> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
> ---
> init/main.c | 28 +++++++++-------
> kernel/irq/handle.c | 23 +++++---------
> kernel/sched.c | 34 +++++++------------
> kernel/sched_cpupri.c | 9 +++--
> mm/slab.c | 85 ++++++++++++++++++++++++++-----------------------
> mm/slub.c | 17 ++++++----
> 6 files changed, 98 insertions(+), 98 deletions(-)
>
> diff --git a/init/main.c b/init/main.c
> index 33ce929..e7a9c18 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -576,6 +576,22 @@ asmlinkage void __init start_kernel(void)
> 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);
> + /*
> + * Setup kernel memory allocators
> + */
> + pidhash_init();
> + vmalloc_init();
> + vfs_caches_init_early();
> + mem_init();
> + kmem_cache_init();

Looks quite OK to me. The comment above maybe misleading?

The bootmem allocations of course are required because some hashes may
need to be larger than MAX_ORDER without using vmalloc.

kmem_cache_init (and mem_init, partially) sets up the kernel memory
allocators...

I can take a look at the SLQB side.