From: Nathan Fontenot <nfont@linux.vnet.ibm.com>
To: Michael Bringmann <mwb@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Cc: John Allen <jallen@linux.vnet.ibm.com>,
Tyrel Datwyler <tyreld@linux.vnet.ibm.com>,
Thomas Falcon <tlfalcon@linux.vnet.ibm.com>
Subject: Re: [PATCH v07 1/9] hotplug/cpu: Conditionally acquire/release DRC index
Date: Mon, 23 Jul 2018 12:42:14 -0500 [thread overview]
Message-ID: <a7e92a8f-2bb9-95e7-78ca-b7440f80c7f7@linux.vnet.ibm.com> (raw)
In-Reply-To: <a7e202c1-177f-db1b-912f-8773a551feec@linux.vnet.ibm.com>
On 07/13/2018 03:17 PM, Michael Bringmann wrote:
> powerpc/cpu: Modify dlpar_cpu_add and dlpar_cpu_remove to allow the
> skipping of DRC index acquire or release operations during the CPU
> add or remove operations. This is intended to support subsequent
> changes to provide a 'CPU readd' operation.
>
> Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
> ---
> Changes in patch:
> -- Move new validity check added to pseries_smp_notifier
> to another patch
> -- Revise one of checks for 'acquire_drc' in dlpar_cpu_add.
> -- Revise one of checks for 'release_drc' in dlpar_cpu_remove.
> ---
> arch/powerpc/platforms/pseries/hotplug-cpu.c | 71 +++++++++++++++-----------
> 1 file changed, 40 insertions(+), 31 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
> index 6ef77ca..7ede3b0 100644
> --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
> +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
> @@ -432,7 +432,7 @@ static bool valid_cpu_drc_index(struct device_node *parent, u32 drc_index)
> return found;
> }
>
> -static ssize_t dlpar_cpu_add(u32 drc_index)
> +static ssize_t dlpar_cpu_add(u32 drc_index, bool acquire_drc)
> {
> struct device_node *dn, *parent;
> int rc, saved_rc;
> @@ -457,19 +457,22 @@ static ssize_t dlpar_cpu_add(u32 drc_index)
> return -EINVAL;
> }
>
> - rc = dlpar_acquire_drc(drc_index);
> - if (rc) {
> - pr_warn("Failed to acquire DRC, rc: %d, drc index: %x\n",
> - rc, drc_index);
> - of_node_put(parent);
> - return -EINVAL;
> + if (acquire_drc) {
> + rc = dlpar_acquire_drc(drc_index);
> + if (rc) {
> + pr_warn("Failed to acquire DRC, rc: %d, drc index: %x\n",
> + rc, drc_index);
> + of_node_put(parent);
> + return -EINVAL;
> + }
> }
>
> dn = dlpar_configure_connector(cpu_to_be32(drc_index), parent);
> if (!dn) {
> pr_warn("Failed call to configure-connector, drc index: %x\n",
> drc_index);
> - dlpar_release_drc(drc_index);
> + if (acquire_drc)
> + dlpar_release_drc(drc_index);
> of_node_put(parent);
> return -EINVAL;
> }
> @@ -484,9 +487,11 @@ static ssize_t dlpar_cpu_add(u32 drc_index)
> pr_warn("Failed to attach node %s, rc: %d, drc index: %x\n",
> dn->name, rc, drc_index);
>
> - rc = dlpar_release_drc(drc_index);
> - if (!rc)
> - dlpar_free_cc_nodes(dn);
> + if (acquire_drc) {
> + rc = dlpar_release_drc(drc_index);
> + if (!rc)
> + dlpar_free_cc_nodes(dn);
> + }
>
> return saved_rc;
> }
> @@ -498,7 +503,7 @@ static ssize_t dlpar_cpu_add(u32 drc_index)
> dn->name, rc, drc_index);
>
> rc = dlpar_detach_node(dn);
> - if (!rc)
> + if (!rc && acquire_drc)
> dlpar_release_drc(drc_index);
>
> return saved_rc;
> @@ -566,7 +571,8 @@ static int dlpar_offline_cpu(struct device_node *dn)
>
> }
>
> -static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
> +static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index,
> + bool release_drc)
> {
> int rc;
>
> @@ -579,12 +585,14 @@ static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
> return -EINVAL;
> }
>
> - rc = dlpar_release_drc(drc_index);
> - if (rc) {
> - pr_warn("Failed to release drc (%x) for CPU %s, rc: %d\n",
> - drc_index, dn->name, rc);
> - dlpar_online_cpu(dn);
> - return rc;
> + if (release_drc) {
> + rc = dlpar_release_drc(drc_index);
> + if (rc) {
> + pr_warn("Failed to release drc (%x) for CPU %s, rc: %d\n",
> + drc_index, dn->name, rc);
> + dlpar_online_cpu(dn);
> + return rc;
> + }
> }
>
> rc = dlpar_detach_node(dn);
> @@ -593,8 +601,9 @@ static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
>
> pr_warn("Failed to detach CPU %s, rc: %d", dn->name, rc);
>
> - rc = dlpar_acquire_drc(drc_index);
> - if (!rc)
> + if (release_drc)
> + rc = dlpar_acquire_drc(drc_index);
> + if (!release_drc || !rc)
> dlpar_online_cpu(dn);
This is likely wrong. At this point you're in a if (rc) so rc is already
non-zero. If release_drc is false this checks an invalid rc state.
-Nathan
>
> return saved_rc;
> @@ -622,7 +631,7 @@ static struct device_node *cpu_drc_index_to_dn(u32 drc_index)
> return dn;
> }
>
> -static int dlpar_cpu_remove_by_index(u32 drc_index)
> +static int dlpar_cpu_remove_by_index(u32 drc_index, bool release_drc)
> {
> struct device_node *dn;
> int rc;
> @@ -634,7 +643,7 @@ static int dlpar_cpu_remove_by_index(u32 drc_index)
> return -ENODEV;
> }
>
> - rc = dlpar_cpu_remove(dn, drc_index);
> + rc = dlpar_cpu_remove(dn, drc_index, release_drc);
> of_node_put(dn);
> return rc;
> }
> @@ -699,7 +708,7 @@ static int dlpar_cpu_remove_by_count(u32 cpus_to_remove)
> }
>
> for (i = 0; i < cpus_to_remove; i++) {
> - rc = dlpar_cpu_remove_by_index(cpu_drcs[i]);
> + rc = dlpar_cpu_remove_by_index(cpu_drcs[i], true);
> if (rc)
> break;
>
> @@ -710,7 +719,7 @@ static int dlpar_cpu_remove_by_count(u32 cpus_to_remove)
> pr_warn("CPU hot-remove failed, adding back removed CPUs\n");
>
> for (i = 0; i < cpus_removed; i++)
> - dlpar_cpu_add(cpu_drcs[i]);
> + dlpar_cpu_add(cpu_drcs[i], true);
>
> rc = -EINVAL;
> } else {
> @@ -780,7 +789,7 @@ static int dlpar_cpu_add_by_count(u32 cpus_to_add)
> }
>
> for (i = 0; i < cpus_to_add; i++) {
> - rc = dlpar_cpu_add(cpu_drcs[i]);
> + rc = dlpar_cpu_add(cpu_drcs[i], true);
> if (rc)
> break;
>
> @@ -791,7 +800,7 @@ static int dlpar_cpu_add_by_count(u32 cpus_to_add)
> pr_warn("CPU hot-add failed, removing any added CPUs\n");
>
> for (i = 0; i < cpus_added; i++)
> - dlpar_cpu_remove_by_index(cpu_drcs[i]);
> + dlpar_cpu_remove_by_index(cpu_drcs[i], true);
>
> rc = -EINVAL;
> } else {
> @@ -817,7 +826,7 @@ int dlpar_cpu(struct pseries_hp_errorlog *hp_elog)
> if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
> rc = dlpar_cpu_remove_by_count(count);
> else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
> - rc = dlpar_cpu_remove_by_index(drc_index);
> + rc = dlpar_cpu_remove_by_index(drc_index, true);
> else
> rc = -EINVAL;
> break;
> @@ -825,7 +834,7 @@ int dlpar_cpu(struct pseries_hp_errorlog *hp_elog)
> if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
> rc = dlpar_cpu_add_by_count(count);
> else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
> - rc = dlpar_cpu_add(drc_index);
> + rc = dlpar_cpu_add(drc_index, true);
> else
> rc = -EINVAL;
> break;
> @@ -850,7 +859,7 @@ static ssize_t dlpar_cpu_probe(const char *buf, size_t count)
> if (rc)
> return -EINVAL;
>
> - rc = dlpar_cpu_add(drc_index);
> + rc = dlpar_cpu_add(drc_index, true);
>
> return rc ? rc : count;
> }
> @@ -871,7 +880,7 @@ static ssize_t dlpar_cpu_release(const char *buf, size_t count)
> return -EINVAL;
> }
>
> - rc = dlpar_cpu_remove(dn, drc_index);
> + rc = dlpar_cpu_remove(dn, drc_index, true);
> of_node_put(dn);
>
> return rc ? rc : count;
>
next prev parent reply other threads:[~2018-07-23 17:42 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-13 20:16 [PATCH v07 0/9] powerpc/hotplug: Update affinity for migrated CPUs Michael Bringmann
2018-07-13 20:17 ` [PATCH v07 1/9] hotplug/cpu: Conditionally acquire/release DRC index Michael Bringmann
2018-07-23 17:42 ` Nathan Fontenot [this message]
2018-07-13 20:18 ` [PATCH v07 2/9] hotplug/cpu: Add operation queuing function Michael Bringmann
2018-07-23 15:54 ` John Allen
2018-07-25 15:49 ` Michael Bringmann
2018-07-27 5:57 ` Michael Ellerman
2018-07-23 17:51 ` Nathan Fontenot
2018-07-25 15:57 ` Michael Bringmann
2018-07-27 6:09 ` Michael Ellerman
2018-07-13 20:18 ` [PATCH v07 3/9] hotplug/cpu: Provide CPU readd operation Michael Bringmann
2018-07-13 20:18 ` [PATCH v07 4/9] mobility/numa: Ensure numa update does not overlap Michael Bringmann
2018-07-13 20:18 ` [PATCH v07 5/9] numa: Disable/enable arch_update_cpu_topology Michael Bringmann
2018-07-13 20:18 ` [PATCH v07 6/9] pmt/numa: Disable arch_update_cpu_topology during CPU readd Michael Bringmann
2018-07-24 20:38 ` Nathan Fontenot
2018-07-13 20:18 ` [PATCH v07 7/9] powerpc/rtas: Allow disabling rtas_event_scan Michael Bringmann
2018-07-13 20:18 ` [PATCH v07 8/9] hotplug/rtas: No rtas_event_scan during PMT update Michael Bringmann
2018-07-13 20:18 ` [PATCH v07 9/9] hotplug/pmt: Update topology after PMT Michael Bringmann
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