lkml.org 
[lkml]   [2003]   [Apr]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Subject[RFC] clustered apic irq affinity fix for i386
    From
    Date
    Hello all,
    Machines with clustered apics are buggy when it comes to setting irq
    affinity. The function set_ioapic_affinity gladly writes the bottom 8
    bits to the ioapic. This workes great for small smp boxes that are in
    flat apic mode but can cause a bit of trouble for clustered apic boxes
    (including hanging the box).
    What I propose is some minor checking for clustered apic sub arches.
    Before writing to the apic making sure the value came from kirqd (by
    checking pending_irq_balance_apic[irq] against the mask we are about to
    write). kirqd uses cpu_to_logical_apicid to setup the ioapic writes so
    we trust those values. If irqbalance_disabled is true we allow writing
    of any masks, we trust the /proc interface user knows what they are
    doing.
    This is a fairly minimal patch that should still allow both kirqd and
    userspace irq balancing. I would like to see a fix for this problem go
    into the kernel. As you can tell this patch is against 2.5.68 stock.

    Thanks,
    Keith Mannthey

    diff -urN linux-2.5.68/arch/i386/kernel/io_apic.c linux-2.5.68-irqfix/arch/i386/kernel/io_apic.c
    --- linux-2.5.68/arch/i386/kernel/io_apic.c Sat Apr 19 19:49:09 2003
    +++ linux-2.5.68-irqfix/arch/i386/kernel/io_apic.c Thu May 1 19:09:43 2003
    @@ -240,29 +240,6 @@
    clear_IO_APIC_pin(apic, pin);
    }

    -static void set_ioapic_affinity (unsigned int irq, unsigned long mask)
    -{
    - unsigned long flags;
    - int pin;
    - struct irq_pin_list *entry = irq_2_pin + irq;
    -
    - /*
    - * Only the first 8 bits are valid.
    - */
    - mask = mask << 24;
    - spin_lock_irqsave(&ioapic_lock, flags);
    - for (;;) {
    - pin = entry->pin;
    - if (pin == -1)
    - break;
    - io_apic_write(entry->apic, 0x10 + 1 + pin*2, mask);
    - if (!entry->next)
    - break;
    - entry = irq_2_pin + entry->next;
    - }
    - spin_unlock_irqrestore(&ioapic_lock, flags);
    -}
    -
    #if defined(CONFIG_SMP)
    # include <asm/processor.h> /* kernel_thread() */
    # include <linux/kernel_stat.h> /* kstat */
    @@ -672,6 +649,26 @@
    #endif /* defined(CONFIG_SMP) */


    +static void set_ioapic_affinity (unsigned int irq, unsigned long mask)
    +{
    + unsigned long flags;
    + int pin;
    + struct irq_pin_list *entry = irq_2_pin + irq;
    +
    + spin_lock_irqsave(&ioapic_lock, flags);
    + for (;;) {
    + pin = entry->pin;
    + if (pin == -1)
    + break;
    + io_apic_write_affinity(entry->apic, 0x10 + 1 + pin*2, mask,irq);
    + if (!entry->next)
    + break;
    + entry = irq_2_pin + entry->next;
    + }
    + spin_unlock_irqrestore(&ioapic_lock, flags);
    +}
    +
    +
    /*
    * support for broken MP BIOSs, enables hand-redirection of PIRQ0-7 to
    * specific CPU-side IRQs.
    @@ -822,6 +819,7 @@
    if (irq_entry == -1)
    continue;
    irq = pin_2_irq(irq_entry, ioapic, pin);
    + pending_irq_balance_apicid[irq] = mask;
    set_ioapic_affinity(irq, mask);
    }

    diff -urN linux-2.5.68/include/asm-i386/mach-bigsmp/mach_apic.h linux-2.5.68-irqfix/include/asm-i386/mach-bigsmp/mach_apic.h
    --- linux-2.5.68/include/asm-i386/mach-bigsmp/mach_apic.h Sat Apr 19 19:51:08 2003
    +++ linux-2.5.68-irqfix/include/asm-i386/mach-bigsmp/mach_apic.h Thu May 1 19:12:37 2003
    @@ -115,4 +115,21 @@
    return (1);
    }

    +extern int __cacheline_aligned pending_irq_balance_apicid[];
    +extern int irqbalance_disabled;
    +/*we want to be careful what we write we are in clustered mode
    + *if the mask came from pending_irq_balance_apicid we are ok because
    + *it was generated with cpu_to_logical_apicid*/
    +static inline void io_apic_write_affinity(unsigned int apic, unsigned int reg, unsigned int mask, unsigned int irq)
    +{
    + if ((pending_irq_balance_apicid[irq] == mask) || (irqbalance_disabled))
    + {
    + mask = mask << 24;
    + io_apic_write(apic,reg,mask);
    + }
    + else
    + {
    + printk ("Trying to write abartry affinity value to ioapic! Not allowed!");
    + }
    +}
    #endif /* __ASM_MACH_APIC_H */
    diff -urN linux-2.5.68/include/asm-i386/mach-default/mach_apic.h linux-2.5.68-irqfix/include/asm-i386/mach-default/mach_apic.h
    --- linux-2.5.68/include/asm-i386/mach-default/mach_apic.h Sat Apr 19 19:51:19 2003
    +++ linux-2.5.68-irqfix/include/asm-i386/mach-default/mach_apic.h Thu May 1 19:18:44 2003
    @@ -99,4 +99,11 @@
    return test_bit(boot_cpu_physical_apicid, &phys_cpu_present_map);
    }

    +static inline void io_apic_write_affinity(unsigned int apic, unsigned int reg, unsigned int mask,int irq)
    +{
    + /*only the first 8 bits are valid*/
    + mask = mask << 24;
    + io_apic_write(apic,reg,mask);
    +}
    +
    #endif /* __ASM_MACH_APIC_H */
    diff -urN linux-2.5.68/include/asm-i386/mach-numaq/mach_apic.h linux-2.5.68-irqfix/include/asm-i386/mach-numaq/mach_apic.h
    --- linux-2.5.68/include/asm-i386/mach-numaq/mach_apic.h Sat Apr 19 19:49:17 2003
    +++ linux-2.5.68-irqfix/include/asm-i386/mach-numaq/mach_apic.h Thu May 1 19:13:40 2003
    @@ -103,4 +103,22 @@
    return (1);
    }

    +extern int __cacheline_aligned pending_irq_balance_apicid[];
    +extern int irqbalance_disabled;
    +/*we want to be careful what we write we are in clustered mode
    + *if the mask came from pending_irq_balance_apicid we are ok because
    + *it was generated with cpu_to_logical_apicid*/
    +static inline void io_apic_write_affinity(unsigned int apic, unsigned int reg, unsigned int mask, unsigned int irq)
    +{
    + if ((pending_irq_balance_apicid[irq] == mask) || (irqbalance_disabled))
    + {
    + mask = mask << 24;
    + io_apic_write(apic,reg,mask);
    + }
    + else
    + {
    + printk ("Trying to write abartry affinity value to ioapic! Not allowed!");
    + }
    +}
    +
    #endif /* __ASM_MACH_APIC_H */
    diff -urN linux-2.5.68/include/asm-i386/mach-summit/mach_apic.h linux-2.5.68-irqfix/include/asm-i386/mach-summit/mach_apic.h
    --- linux-2.5.68/include/asm-i386/mach-summit/mach_apic.h Sat Apr 19 19:50:06 2003
    +++ linux-2.5.68-irqfix/include/asm-i386/mach-summit/mach_apic.h Thu May 1 19:11:17 2003
    @@ -113,4 +113,24 @@
    return test_bit(boot_cpu_physical_apicid, &phys_cpu_present_map);
    }

    +
    +extern int __cacheline_aligned pending_irq_balance_apicid[];
    +extern int irqbalance_disabled;
    +/*we want to be careful what we write we are in clustered mode
    + *if the mask came from pending_irq_balance_apicid we are ok because
    + *it was generated with cpu_to_logical_apicid*/
    +static inline void io_apic_write_affinity(unsigned int apic, unsigned int reg, unsigned int mask, unsigned int irq)
    +{
    + if ((pending_irq_balance_apicid[irq] == mask) || (irqbalance_disabled))
    + {
    + mask = mask << 24;
    + io_apic_write(apic,reg,mask);
    + }
    + else
    + {
    + printk ("Trying to write abartry affinity value to ioapic! Not allowed!");
    + }
    +}
    +
    +
    #endif /* __ASM_MACH_APIC_H */
    diff -urN linux-2.5.68/include/asm-i386/mach-visws/mach_apic.h linux-2.5.68-irqfix/include/asm-i386/mach-visws/mach_apic.h
    --- linux-2.5.68/include/asm-i386/mach-visws/mach_apic.h Sat Apr 19 19:48:49 2003
    +++ linux-2.5.68-irqfix/include/asm-i386/mach-visws/mach_apic.h Thu May 1 19:18:32 2003
    @@ -77,4 +77,11 @@
    return test_bit(boot_cpu_physical_apicid, &phys_cpu_present_map);
    }

    +static inline void io_apic_write_affinity(unsigned int apic, unsigned int reg, unsigned int mask, int irq)
    +{
    + /*only the first 8 bits are valid*/
    + mask = mask << 24;
    + io_apic_write(apic,reg,mask);
    +}
    +
    #endif /* __ASM_MACH_APIC_H */


    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 13:35    [W:4.548 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site