Messages in this thread | | | Date | Mon, 05 May 2008 11:26:49 +0200 | From | Nadia Derbey <> | Subject | Re: [PATCH 01/10] Fix idr_remove() |
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Andrew Morton wrote: > On Tue, 29 Apr 2008 16:33:05 +0200 > Nadia.Derbey@bull.net wrote: > > >>[PATCH 01/10] >> >>This patch fixes idr_remove(): the return inside the loop makes us free only >>a single layer. >> >>Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> >> >>--- >> lib/idr.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >>Index: linux-2.6.25-mm1/lib/idr.c >>=================================================================== >>--- linux-2.6.25-mm1.orig/lib/idr.c 2008-04-25 15:29:00.000000000 +0200 >>+++ linux-2.6.25-mm1/lib/idr.c 2008-04-25 15:48:34.000000000 +0200 >>@@ -385,8 +385,8 @@ void idr_remove(struct idr *idp, int id) >> while (idp->id_free_cnt >= IDR_FREE_MAX) { >> p = alloc_layer(idp); >> kmem_cache_free(idr_layer_cache, p); >>- return; >> } >>+ return; >> } >> EXPORT_SYMBOL(idr_remove); > > > erk, ancient bug. > > I _think_ the implications of this are that an idr tree will grow fatter > than it needs to be, but there is no permanent leak: idr_destroy() will > still free everything, yes?
Yes, exactly. Actually, I've not checked whether all the kernel components call idr_destroy() when needed.
> > And a consequence of the fix is that idr manipulations will now result in > more allocs and frees,
Not necessarily more allocs: this loop keeps IDR_FREE_MAX layers in the free list. So idr_pre_get() should be a noop.
> but the amount of memory which a tree uses will be > less? > > >
Regards, Nadia
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