Messages in this thread | | | Subject | Re: [rfc patch] sched/topology: fix domain reconstruction memory leakage | From | Mike Galbraith <> | Date | Mon, 21 Aug 2017 15:30:29 +0200 |
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On Mon, 2017-08-21 at 10:16 +0200, Peter Zijlstra wrote: > On Sat, Aug 19, 2017 at 08:10:49AM +0200, Mike Galbraith wrote: > > Greetings, > > > > While beating on cpu hotplug with the shiny new topology fixes > > backported, my memory poor 8 socket box fairly quickly leaked itself to > > death, 0c0e776a9b0f being the culprit. With the below applied, box > > took a severe beating overnight without a whimper. > > > > I'm wondering (ergo rfc) if free_sched_groups() shouldn't be renamed to > > put_sched_groups() instead, with overlapping domains taking a group > > reference reference as well so they can put both sg/sgc rather than put > > one free the other. Those places that want an explicit free can pass > > free to only explicitly free sg (or use two functions). Minimalist > > approach works (minus signs, yay), but could perhaps use some "pretty". > > > > sched/topology: fix domain reconstruction memory leakage > > I was sitting on this one: > > https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/commit/?h=sched/core&id=c63d18dd6ea59eec5cba857835f788943ff9f0d5
The comment in the patch reads better to me like so:
@@ -345,15 +346,12 @@ static void free_sched_groups(struct sch static void destroy_sched_domain(struct sched_domain *sd) { /* - * If its an overlapping domain it has private groups, iterate and - * nuke them all. + * A normal sched domain may have multiple group references, an + * overlapping domain, having private groups, only one. Iterate, + * dropping group/capacity references, freeing where none remain. */ - if (sd->flags & SD_OVERLAP) { - free_sched_groups(sd->groups, 1); - } else if (atomic_dec_and_test(&sd->groups->ref)) { - kfree(sd->groups->sgc); - kfree(sd->groups); - } + free_sched_groups(sd->groups, 1); + if (sd->shared && atomic_dec_and_test(&sd->shared->ref)) kfree(sd->shared); kfree(sd);
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