Re: [ckrm-tech] [PATCH 4/6] CKRM: Add guarantee support for mem controller

[Dave Hansen <haveblue@us.ibm.com>]

On Thu, 2005-06-30 at 11:53 -0700, Chandra Seetharaman wrote:
> On Thu, 2005-06-30 at 11:23 -0700, Dave Hansen wrote:
> > On Thu, 2005-06-30 at 11:11 -0700, Chandra Seetharaman wrote:
> > > i don't understand why you think it is a problem to call kfree with lock
> > > held( i agree calling kmalloc with wait flag when a lock is being held
> > > is not correct).
> > 
> > kfree->__cache_free
> > 	->cache_flusharray
> > 	->free_block
> > 	->slab_destroy
> > 	->kmem_freepages
> > 	->free_pages
> > 	->__free_pages
> > 	->__free_pages_ok
> > 	->free_pages_bulk:
> > 
> > 	spin_lock_irqsave(&zone->lock, flags);
> > 
> Oh.... I did not realize Takashi was mentioning zone->lock... i assumed
> zone->lru_lock...
> 
> memory controller does not use zone->lock, it only uses zone->lru_lock..
> I 'll look thru to see if that leads to a deadlock...

static int
free_pages_bulk(struct zone *zone, int count,
                struct list_head *list, unsigned int order)
{
...
        spin_lock_irqsave(&zone->lock, flags);
        while (!list_empty(list) && count--) {
		__free_pages_bulk(page, zone, order);

		/* can't call the allocator in here: /*
		ckrm_clear_page_class(page);
        }
        spin_unlock_irqrestore(&zone->lock, flags);
        return ret;
}

See?

-- Dave

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