From: "Carrillo, Erik G" <erik.g.carrillo@intel.com>
To: "Burakov, Anatoly" <anatoly.burakov@intel.com>,
"rsanford@akamai.com" <rsanford@akamai.com>,
"thomas@monjalon.net" <thomas@monjalon.net>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v2] timer: fix resource leak in finalize
Date: Tue, 7 May 2019 22:04:21 +0000 [thread overview]
Message-ID: <BE54F058557D9A4FAC1D84E2FC6D875723405E77@fmsmsx115.amr.corp.intel.com> (raw)
In-Reply-To: <7baed0b9-432f-be86-5e39-68035bc309a4@intel.com>
Hi Anatoly,
Thanks for the review. Comments in-line:
<...snipped...>
> > #define RTE_MAX_DATA_ELS 64
> > +static const struct rte_memzone *rte_timer_data_mz; static
> > +rte_atomic16_t *rte_timer_mz_refcnt;
> > static struct rte_timer_data *rte_timer_data_arr;
> > static const uint32_t default_data_id;
> > static uint32_t rte_timer_subsystem_initialized; @@ -155,6 +157,7 @@
> > rte_timer_subsystem_init_v1905(void)
> > struct rte_timer_data *data;
> > int i, lcore_id;
> > static const char *mz_name = "rte_timer_mz";
> > + size_t data_arr_size = RTE_MAX_DATA_ELS *
> > +sizeof(*rte_timer_data_arr);
>
> nitpicking, but... const?
>
No problem - I'll make this change if this line persists into the next version.
<...snipped...>
> >
> > @@ -205,8 +216,11 @@
> BIND_DEFAULT_SYMBOL(rte_timer_subsystem_init, _v1905, 19.05);
> > void __rte_experimental
> > rte_timer_subsystem_finalize(void)
> > {
> > - if (rte_timer_data_arr)
> > - rte_free(rte_timer_data_arr);
> > + if (!rte_timer_subsystem_initialized)
> > + return;
> > +
> > + if (rte_atomic16_dec_and_test(rte_timer_mz_refcnt))
> > + rte_memzone_free(rte_timer_data_mz);
>
> I think there's a race here. You may get preempted after test but before
> free, where another secondary could initialize. As far as i know, we also
Indeed, thanks for catching this.
> support a case when secondary initializes after primary stops running.
>
> Let's even suppose that we allow secondary processes to initialize the timer
> subsystem by reserving memzone and checking rte_errno. You would still
> have a chance of two init/deinit conflicting, because there's a hole between
> memzone allocation and atomic increment.
>
> I don't think this race can be resolved in a safe way, so we might just have to
> settle for a memory leak.
>
I don't see a solution here currently either. I'll look at removing the memzone_free()
call and possibly the rte_timer_subsystem_finalize() API, since it seems like
there's no reason for it to exist if it can't free the allocations.
Regards,
Erik
> >
> > rte_timer_subsystem_initialized = 0;
> > }
> >
>
>
> --
> Thanks,
> Anatoly
next prev parent reply other threads:[~2019-05-07 22:04 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-01 19:00 [dpdk-dev] [PATCH] " Erik Gabriel Carrillo
2019-05-01 19:00 ` Erik Gabriel Carrillo
2019-05-02 9:18 ` Burakov, Anatoly
2019-05-02 9:18 ` Burakov, Anatoly
2019-05-02 12:19 ` Carrillo, Erik G
2019-05-02 12:19 ` Carrillo, Erik G
2019-05-02 13:03 ` Burakov, Anatoly
2019-05-02 13:03 ` Burakov, Anatoly
2019-05-02 13:48 ` Carrillo, Erik G
2019-05-02 13:48 ` Carrillo, Erik G
2019-05-03 22:54 ` [dpdk-dev] [PATCH v2] " Erik Gabriel Carrillo
2019-05-03 22:54 ` Erik Gabriel Carrillo
2019-05-07 11:03 ` Burakov, Anatoly
2019-05-07 11:03 ` Burakov, Anatoly
2019-05-07 22:04 ` Carrillo, Erik G [this message]
2019-05-07 22:04 ` Carrillo, Erik G
2019-05-08 8:49 ` Burakov, Anatoly
2019-05-08 8:49 ` Burakov, Anatoly
2019-05-08 23:01 ` Carrillo, Erik G
2019-05-08 23:01 ` Carrillo, Erik G
2019-05-09 7:44 ` Thomas Monjalon
2019-05-09 7:44 ` Thomas Monjalon
2019-05-08 22:35 ` [dpdk-dev] [PATCH v3] " Erik Gabriel Carrillo
2019-05-08 22:35 ` Erik Gabriel Carrillo
2019-05-09 8:29 ` Burakov, Anatoly
2019-05-09 8:29 ` Burakov, Anatoly
2019-06-05 9:33 ` Thomas Monjalon
2019-06-05 9:47 ` Burakov, Anatoly
2019-06-25 16:11 ` [dpdk-dev] [PATCH 0/2] Fix timer resource leak Anatoly Burakov
2019-07-05 13:20 ` [dpdk-dev] [PATCH v2 0/1] " Anatoly Burakov
2019-07-05 17:22 ` [dpdk-dev] [PATCH v3 " Anatoly Burakov
2019-07-05 17:22 ` [dpdk-dev] [PATCH v3 1/1] timer: fix resource leak in finalize Anatoly Burakov
2019-07-05 22:06 ` Thomas Monjalon
2019-07-05 13:20 ` [dpdk-dev] [PATCH v2 " Anatoly Burakov
2019-06-25 16:11 ` [dpdk-dev] [PATCH 1/2] eal: add internal locks for timer lib into EAL Anatoly Burakov
2019-06-27 18:41 ` Carrillo, Erik G
2019-07-04 9:09 ` David Marchand
2019-07-04 10:44 ` Burakov, Anatoly
2019-06-25 16:11 ` [dpdk-dev] [PATCH 2/2] timer: fix resource leak in finalize Anatoly Burakov
2019-06-27 18:48 ` Carrillo, Erik G
2019-07-04 9:10 ` David Marchand
2019-07-04 10:45 ` Burakov, Anatoly
2019-07-04 10:50 ` David Marchand
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