Messages in this thread | | | Date | Thu, 29 Jan 2015 16:51:31 +0900 | From | Joonsoo Kim <> | Subject | Re: [PATCH v3 3/3] mm: cma: release trigger |
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On Tue, Jan 27, 2015 at 09:22:57PM -0500, Sasha Levin wrote: > Provides a userspace interface to trigger a CMA release. > > Usage: > > echo [pages] > free > > This would provide testing/fuzzing access to the CMA release paths. > > Signed-off-by: Sasha Levin <sasha.levin@oracle.com> > --- > mm/cma_debug.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 56 insertions(+) > > diff --git a/mm/cma_debug.c b/mm/cma_debug.c > index 5bd6863..c29f029 100644 > --- a/mm/cma_debug.c > +++ b/mm/cma_debug.c > @@ -39,6 +39,59 @@ static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem) > spin_unlock(&cma->mem_head_lock); > } > > +static struct cma_mem *cma_get_entry_from_list(struct cma *cma) > +{ > + struct cma_mem *mem = NULL; > + > + spin_lock(&cma->mem_head_lock); > + if (!hlist_empty(&cma->mem_head)) { > + mem = hlist_entry(cma->mem_head.first, struct cma_mem, node); > + hlist_del_init(&mem->node); > + } > + spin_unlock(&cma->mem_head_lock); > + > + return mem; > +} > + > +static int cma_free_mem(struct cma *cma, int count) > +{ > + struct cma_mem *mem = NULL; > + > + while (count) { > + mem = cma_get_entry_from_list(cma); > + if (mem == NULL) > + return 0; > + > + if (mem->n <= count) { > + cma_release(cma, mem->p, mem->n); > + count -= mem->n; > + kfree(mem); > + } else if (cma->order_per_bit == 0) { > + cma_release(cma, mem->p, count); > + mem->p += count; > + mem->n -= count; > + count = 0; > + cma_add_to_cma_mem_list(cma, mem); > + } else { > + cma_add_to_cma_mem_list(cma, mem); > + break; > + } > + }
Hmm... I'm not sure we need to deal with "mem->m < count" case. It is not suitable for any cma_alloc/release usecase. And, I'd like to insert some error log to last case rather than silently ignoring the request.
Thanks.
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