Re: Spinlocks waiting with interrupts disabled / preempt disabled.

From: Christoph Lameter
Date: Fri May 09 2008 - 14:00:33 EST


On Fri, 9 May 2008, Peter Zijlstra wrote:

> > A third solution would be to look at this problem on a case-by-case
> > basis. In the case under discussion, there may be other kernel bugs
> > that aggravate the problem (it is an old kernel after all) and maybe
> > this just means the address_space.tree_lock ought to be replaced with
> > something else (though I wouldn't claim to know what).
>
> That has been done by Nick Piggin, the lockless pagecache work removes
> the read side of the tree_lock.

When is that going to get merged? find_get_page is still:

struct page * find_get_page(struct address_space *mapping, pgoff_t offset)
{
struct page *page;

read_lock_irq(&mapping->tree_lock);
page = radix_tree_lookup(&mapping->page_tree, offset);
if (page)
page_cache_get(page);
read_unlock_irq(&mapping->tree_lock);
return page;
}
EXPORT_SYMBOL(find_get_page);

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