Messages in this thread | | | Date | Thu, 28 Jun 2007 22:37:34 -0700 (PDT) | Subject | Re: [PATCH] Containment measures for slab objects on scatter gather lists | From | David Miller <> |
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From: Andrew Morton <akpm@linux-foundation.org> Date: Thu, 28 Jun 2007 22:24:24 -0700
> So what happens when two quite different threads of control are doing > IO against two hunks of kmalloced memory which happen to come from the same > page? Either some (kernel-wide) locking is needed, or that pageframe needs > to be treated as readonly?
Or you put an atomic_t at the beginning or tail of every SLAB object. It's a space cost not a runtime cost for the common case which is:
smp_rmb(); if (atomic_read(&slab_obj->count) == 1) really_free_it(); else if (atomic_dec_and_test(...))
Note I don't like this variant either. :)
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