Re: [PATCH] convert sighand_cache to use SLAB_DESTROY_BY_RCU

[Hugh Dickins <hugh@veritas.com>]

On Fri, 17 Feb 2006, Oleg Nesterov wrote:
> This patch borrows a clever Hugh's 'struct anon_vma' trick.
> 
> Without tasklist_lock held we can't trust task->sighand until we
> locked it and re-checked that it is still the same.
> 
> But this means we don't need to defer 'kmem_cache_free(sighand)'.
> We can return the memory to slab immediately, all we need is to
> be sure that sighand->siglock can't dissapear inside rcu protected
> section.
> 
> To do so we need to initialize ->siglock inside ctor function,
> SLAB_DESTROY_BY_RCU does the rest.

Yes, that looks a good use of SLAB_DESTROY_BY_RCU to me: thanks!

Hugh
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