Re: [PATCH] Remove special case in kmem_getpages()

[Matthew Wilcox <matthew@wil.cx>]

On Mon, Jan 24, 2005 at 07:58:03PM -0500, Brian Gerst wrote:
> Matthew Wilcox wrote:
> >__get_free_pages() calls alloc_pages, finds the page_address() and
> >throws away the struct page *.  Slab then calls virt_to_page to get it
> >back again.  Much more efficient for slab to call alloc_pages itself,
> >as well as making the NUMA and non-NUMA cases more similarr to each other.
> 
> Here is a better patch:

I disagree.  This disables the alloc_pages_current() optimisation.
I considered this option and rejected it.

> Remove the special case of nodeid == -1.  Instead, use numa_node_id() 
> when calling cache_grow().
> 
> Signed-off-by: Brian Gerst <bgerst@didntduck.org>

> diff -urN linux-2.6.11-rc2-bk/mm/slab.c linux/mm/slab.c
> --- linux-2.6.11-rc2-bk/mm/slab.c	2005-01-22 01:58:25.000000000 -0500
> +++ linux/mm/slab.c	2005-01-24 15:35:08.000000000 -0500
> @@ -893,17 +893,11 @@
>  	int i;
>  
>  	flags |= cachep->gfpflags;
> -	if (likely(nodeid == -1)) {
> -		addr = (void*)__get_free_pages(flags, cachep->gfporder);
> -		if (!addr)
> -			return NULL;
> -		page = virt_to_page(addr);
> -	} else {
> -		page = alloc_pages_node(nodeid, flags, cachep->gfporder);
> -		if (!page)
> -			return NULL;
> -		addr = page_address(page);
> -	}
> +
> +	page = alloc_pages_node(nodeid, flags, cachep->gfporder);
> +	if (!page)
> +		return NULL;
> +	addr = page_address(page);
>  
>  	i = (1 << cachep->gfporder);
>  	if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
> @@ -2065,7 +2059,7 @@
>  
>  	if (unlikely(!ac->avail)) {
>  		int x;
> -		x = cache_grow(cachep, flags, -1);
> +		x = cache_grow(cachep, flags, numa_node_id());
>  		
>  		// cache_grow can reenable interrupts, then ac could change.
>  		ac = ac_data(cachep);


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