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Date: Fri, 18 Dec 2009 08:40:18 -0600
From: Dimitri Sivanich <sivanich@....com>
To: Suresh Siddha <suresh.b.siddha@...el.com>
Cc: Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
LKML <linux-kernel@...r.kernel.org>,
John Blackwood <john.blackwood@...r.com>
Subject: Re: [patch] x86, irq: allow 0xff for /proc/irq/[n]/smp_affinity on
a 8 cpu system
Acked-by: Dimitri Sivanich <sivanich@....com>
On Thu, Dec 17, 2009 at 06:29:46PM -0800, Suresh Siddha wrote:
> John Blackwood reported:
> > on an older Dell PowerEdge 6650 system with 8 cpus (4 are hyper-threaded),
> > and 32 bit (x86) kernel, once you change the irq smp_affinity of an irq
> > to be less than all cpus in the system, you can never change really the
> > irq smp_affinity back to be all cpus in the system (0xff) again,
> > even though no error status is returned on the "/bin/echo ff >
> > /proc/irq/[n]/smp_affinity" operation.
> >
> > This is due to that fact that BAD_APICID has the same value as
> > all cpus (0xff) on 32bit kernels, and thus the value returned from
> > set_desc_affinity() via the cpu_mask_to_apicid_and() function is treated
> > as a failure in set_ioapic_affinity_irq_desc(), and no affinity changes
> > are made.
>
> set_desc_affinity() is already checking if the incoming cpu mask
> intersects with the cpu online mask or not. So there is no need
> for the apic op cpu_mask_to_apicid_and() to check again
> and return BAD_APICID.
>
> Remove the BAD_APICID return value from cpu_mask_to_apicid_and()
> and also fix set_desc_affinity() to return -1 instead of using BAD_APICID
> to represent error conditions (as cpu_mask_to_apicid_and() can return
> logical or physical apicid values and BAD_APICID is really to represent
> bad physical apic id).
>
> Reported-by: John Blackwood <john.blackwood@...r.com>
> Root-caused-by: John Blackwood <john.blackwood@...r.com>
> Signed-off-by: Suresh Siddha <suresh.b.siddha@...el.com>
> ---
> arch/x86/include/asm/hw_irq.h | 3 ++-
> arch/x86/kernel/apic/apic_flat_64.c | 5 +----
> arch/x86/kernel/apic/bigsmp_32.c | 5 +----
> arch/x86/kernel/apic/io_apic.c | 32 ++++++++++++++------------------
> arch/x86/kernel/apic/x2apic_cluster.c | 5 +----
> arch/x86/kernel/apic/x2apic_phys.c | 5 +----
> arch/x86/kernel/apic/x2apic_uv_x.c | 5 +----
> arch/x86/kernel/uv_irq.c | 3 +--
> 8 files changed, 22 insertions(+), 41 deletions(-)
>
> diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h
> index 08c48a8..eeac829 100644
> --- a/arch/x86/include/asm/hw_irq.h
> +++ b/arch/x86/include/asm/hw_irq.h
> @@ -103,7 +103,8 @@ extern int assign_irq_vector(int, struct irq_cfg *, const struct cpumask *);
> extern void send_cleanup_vector(struct irq_cfg *);
>
> struct irq_desc;
> -extern unsigned int set_desc_affinity(struct irq_desc *, const struct cpumask *);
> +extern unsigned int set_desc_affinity(struct irq_desc *, const struct cpumask *,
> + unsigned int *dest_id);
> extern int IO_APIC_get_PCI_irq_vector(int bus, int devfn, int pin, struct io_apic_irq_attr *irq_attr);
> extern void setup_ioapic_dest(void);
>
> diff --git a/arch/x86/kernel/apic/apic_flat_64.c b/arch/x86/kernel/apic/apic_flat_64.c
> index d0c99ab..eacbd2b 100644
> --- a/arch/x86/kernel/apic/apic_flat_64.c
> +++ b/arch/x86/kernel/apic/apic_flat_64.c
> @@ -306,10 +306,7 @@ physflat_cpu_mask_to_apicid_and(const struct cpumask *cpumask,
> if (cpumask_test_cpu(cpu, cpu_online_mask))
> break;
> }
> - if (cpu < nr_cpu_ids)
> - return per_cpu(x86_cpu_to_apicid, cpu);
> -
> - return BAD_APICID;
> + return per_cpu(x86_cpu_to_apicid, cpu);
> }
>
> struct apic apic_physflat = {
> diff --git a/arch/x86/kernel/apic/bigsmp_32.c b/arch/x86/kernel/apic/bigsmp_32.c
> index 38dcecf..cb804c5 100644
> --- a/arch/x86/kernel/apic/bigsmp_32.c
> +++ b/arch/x86/kernel/apic/bigsmp_32.c
> @@ -131,10 +131,7 @@ static unsigned int bigsmp_cpu_mask_to_apicid_and(const struct cpumask *cpumask,
> if (cpumask_test_cpu(cpu, cpu_online_mask))
> break;
> }
> - if (cpu < nr_cpu_ids)
> - return bigsmp_cpu_to_logical_apicid(cpu);
> -
> - return BAD_APICID;
> + return bigsmp_cpu_to_logical_apicid(cpu);
> }
>
> static int bigsmp_phys_pkg_id(int cpuid_apic, int index_msb)
> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
> index 11a5851..de00c46 100644
> --- a/arch/x86/kernel/apic/io_apic.c
> +++ b/arch/x86/kernel/apic/io_apic.c
> @@ -2276,26 +2276,28 @@ static void __target_IO_APIC_irq(unsigned int irq, unsigned int dest, struct irq
>
> /*
> * Either sets desc->affinity to a valid value, and returns
> - * ->cpu_mask_to_apicid of that, or returns BAD_APICID and
> + * ->cpu_mask_to_apicid of that in dest_id, or returns -1 and
> * leaves desc->affinity untouched.
> */
> unsigned int
> -set_desc_affinity(struct irq_desc *desc, const struct cpumask *mask)
> +set_desc_affinity(struct irq_desc *desc, const struct cpumask *mask,
> + unsigned int *dest_id)
> {
> struct irq_cfg *cfg;
> unsigned int irq;
>
> if (!cpumask_intersects(mask, cpu_online_mask))
> - return BAD_APICID;
> + return -1;
>
> irq = desc->irq;
> cfg = desc->chip_data;
> if (assign_irq_vector(irq, cfg, mask))
> - return BAD_APICID;
> + return -1;
>
> cpumask_copy(desc->affinity, mask);
>
> - return apic->cpu_mask_to_apicid_and(desc->affinity, cfg->domain);
> + *dest_id = apic->cpu_mask_to_apicid_and(desc->affinity, cfg->domain);
> + return 0;
> }
>
> static int
> @@ -2311,12 +2313,11 @@ set_ioapic_affinity_irq_desc(struct irq_desc *desc, const struct cpumask *mask)
> cfg = desc->chip_data;
>
> spin_lock_irqsave(&ioapic_lock, flags);
> - dest = set_desc_affinity(desc, mask);
> - if (dest != BAD_APICID) {
> + ret = set_desc_affinity(desc, mask, &dest);
> + if (!ret) {
> /* Only the high 8 bits are valid. */
> dest = SET_APIC_LOGICAL_ID(dest);
> __target_IO_APIC_irq(irq, dest, cfg);
> - ret = 0;
> }
> spin_unlock_irqrestore(&ioapic_lock, flags);
>
> @@ -3351,8 +3352,7 @@ static int set_msi_irq_affinity(unsigned int irq, const struct cpumask *mask)
> struct msi_msg msg;
> unsigned int dest;
>
> - dest = set_desc_affinity(desc, mask);
> - if (dest == BAD_APICID)
> + if (set_desc_affinity(desc, mask, &dest))
> return -1;
>
> cfg = desc->chip_data;
> @@ -3384,8 +3384,7 @@ ir_set_msi_irq_affinity(unsigned int irq, const struct cpumask *mask)
> if (get_irte(irq, &irte))
> return -1;
>
> - dest = set_desc_affinity(desc, mask);
> - if (dest == BAD_APICID)
> + if (set_desc_affinity(desc, mask, &dest))
> return -1;
>
> irte.vector = cfg->vector;
> @@ -3567,8 +3566,7 @@ static int dmar_msi_set_affinity(unsigned int irq, const struct cpumask *mask)
> struct msi_msg msg;
> unsigned int dest;
>
> - dest = set_desc_affinity(desc, mask);
> - if (dest == BAD_APICID)
> + if (set_desc_affinity(desc, mask, &dest))
> return -1;
>
> cfg = desc->chip_data;
> @@ -3623,8 +3621,7 @@ static int hpet_msi_set_affinity(unsigned int irq, const struct cpumask *mask)
> struct msi_msg msg;
> unsigned int dest;
>
> - dest = set_desc_affinity(desc, mask);
> - if (dest == BAD_APICID)
> + if (set_desc_affinity(desc, mask, &dest))
> return -1;
>
> cfg = desc->chip_data;
> @@ -3730,8 +3727,7 @@ static int set_ht_irq_affinity(unsigned int irq, const struct cpumask *mask)
> struct irq_cfg *cfg;
> unsigned int dest;
>
> - dest = set_desc_affinity(desc, mask);
> - if (dest == BAD_APICID)
> + if (set_desc_affinity(desc, mask, &dest))
> return -1;
>
> cfg = desc->chip_data;
> diff --git a/arch/x86/kernel/apic/x2apic_cluster.c b/arch/x86/kernel/apic/x2apic_cluster.c
> index a5371ec..cf69c59 100644
> --- a/arch/x86/kernel/apic/x2apic_cluster.c
> +++ b/arch/x86/kernel/apic/x2apic_cluster.c
> @@ -148,10 +148,7 @@ x2apic_cpu_mask_to_apicid_and(const struct cpumask *cpumask,
> break;
> }
>
> - if (cpu < nr_cpu_ids)
> - return per_cpu(x86_cpu_to_logical_apicid, cpu);
> -
> - return BAD_APICID;
> + return per_cpu(x86_cpu_to_logical_apicid, cpu);
> }
>
> static unsigned int x2apic_cluster_phys_get_apic_id(unsigned long x)
> diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
> index a8989aa..8972f38 100644
> --- a/arch/x86/kernel/apic/x2apic_phys.c
> +++ b/arch/x86/kernel/apic/x2apic_phys.c
> @@ -146,10 +146,7 @@ x2apic_cpu_mask_to_apicid_and(const struct cpumask *cpumask,
> break;
> }
>
> - if (cpu < nr_cpu_ids)
> - return per_cpu(x86_cpu_to_apicid, cpu);
> -
> - return BAD_APICID;
> + return per_cpu(x86_cpu_to_apicid, cpu);
> }
>
> static unsigned int x2apic_phys_get_apic_id(unsigned long x)
> diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
> index b684bb3..d56b0ef 100644
> --- a/arch/x86/kernel/apic/x2apic_uv_x.c
> +++ b/arch/x86/kernel/apic/x2apic_uv_x.c
> @@ -225,10 +225,7 @@ uv_cpu_mask_to_apicid_and(const struct cpumask *cpumask,
> if (cpumask_test_cpu(cpu, cpu_online_mask))
> break;
> }
> - if (cpu < nr_cpu_ids)
> - return per_cpu(x86_cpu_to_apicid, cpu);
> -
> - return BAD_APICID;
> + return per_cpu(x86_cpu_to_apicid, cpu);
> }
>
> static unsigned int x2apic_get_apic_id(unsigned long x)
> diff --git a/arch/x86/kernel/uv_irq.c b/arch/x86/kernel/uv_irq.c
> index 61d805d..ece73d8 100644
> --- a/arch/x86/kernel/uv_irq.c
> +++ b/arch/x86/kernel/uv_irq.c
> @@ -215,8 +215,7 @@ static int uv_set_irq_affinity(unsigned int irq, const struct cpumask *mask)
> unsigned long mmr_offset;
> unsigned mmr_pnode;
>
> - dest = set_desc_affinity(desc, mask);
> - if (dest == BAD_APICID)
> + if (set_desc_affinity(desc, mask, &dest))
> return -1;
>
> mmr_value = 0;
>
--
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