Re: [PATCH v5 31/45] blackfin/smp: Use get/put_online_cpus_atomic() to prevent CPU offline
On Tue, Jan 22, 2013 at 3:41 PM, Srivatsa S. Bhat
wrote:
> Once stop_machine() is gone from the CPU offline path, we won't be able to
> depend on preempt_disable() or local_irq_disable() to prevent CPUs from
> going offline from under us.
>
> Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going offline,
> while invoking from atomic context.
>
> Cc: Mike Frysinger
> Cc: Bob Liu
> Cc: Steven Miao
> Cc: uclinux-dist-de...@blackfin.uclinux.org
> Signed-off-by: Srivatsa S. Bhat
Thanks, will be applied to my blackfin arch tree.
> ---
>
> arch/blackfin/mach-common/smp.c |6 --
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/blackfin/mach-common/smp.c b/arch/blackfin/mach-common/smp.c
> index bb61ae4..6cc6d7a 100644
> --- a/arch/blackfin/mach-common/smp.c
> +++ b/arch/blackfin/mach-common/smp.c
> @@ -194,6 +194,7 @@ void send_ipi(const struct cpumask *cpumask, enum
> ipi_message_type msg)
> struct ipi_data *bfin_ipi_data;
> unsigned long flags;
>
> + get_online_cpus_atomic();
> local_irq_save(flags);
> smp_mb();
> for_each_cpu(cpu, cpumask) {
> @@ -205,6 +206,7 @@ void send_ipi(const struct cpumask *cpumask, enum
> ipi_message_type msg)
> }
>
> local_irq_restore(flags);
> + put_online_cpus_atomic();
> }
>
> void arch_send_call_function_single_ipi(int cpu)
> @@ -238,13 +240,13 @@ void smp_send_stop(void)
> {
> cpumask_t callmap;
>
> - preempt_disable();
> + get_online_cpus_atomic();
> cpumask_copy(&callmap, cpu_online_mask);
> cpumask_clear_cpu(smp_processor_id(), &callmap);
> if (!cpumask_empty(&callmap))
> send_ipi(&callmap, BFIN_IPI_CPU_STOP);
>
> - preempt_enable();
> + put_online_cpus_atomic();
>
> return;
> }
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majord...@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
--
Regards,
--Bob
___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [RFC PATCH v4 7/13] memory-hotplug : remove_memory calls __remove_pages
On Wed, Jul 18, 2012 at 6:12 PM, Yasuaki Ishimatsu
wrote:
> The patch adds __remove_pages() to remove_memory(). Then the range of
> phys_start_pfn argument and nr_pages argument in __remove_pagse() may
> have different zone. So zone argument is removed from __remove_pages()
> and __remove_pages() caluculates zone in each section.
>
> When CONFIG_SPARSEMEM_VMEMMAP is defined, there is no way to remove a memmap.
> So __remove_section only calls unregister_memory_section().
>
> CC: David Rientjes
> CC: Jiang Liu
> CC: Len Brown
> CC: Benjamin Herrenschmidt
> CC: Paul Mackerras
> CC: Christoph Lameter
> Cc: Minchan Kim
> CC: Andrew Morton
> CC: KOSAKI Motohiro
> CC: Wen Congyang
> Signed-off-by: Yasuaki Ishimatsu
>
> ---
> arch/powerpc/platforms/pseries/hotplug-memory.c |5 +
> include/linux/memory_hotplug.h |3 +--
> mm/memory_hotplug.c | 19 ---
> 3 files changed, 14 insertions(+), 13 deletions(-)
>
> Index: linux-3.5-rc6/mm/memory_hotplug.c
> ===
> --- linux-3.5-rc6.orig/mm/memory_hotplug.c 2012-07-18 18:00:27.440145432
> +0900
> +++ linux-3.5-rc6/mm/memory_hotplug.c 2012-07-18 18:01:02.070712487 +0900
> @@ -275,11 +275,14 @@ static int __meminit __add_section(int n
> #ifdef CONFIG_SPARSEMEM_VMEMMAP
> static int __remove_section(struct zone *zone, struct mem_section *ms)
> {
> - /*
> -* XXX: Freeing memmap with vmemmap is not implement yet.
> -* This should be removed later.
> -*/
> - return -EBUSY;
> + int ret = -EINVAL;
> +
> + if (!valid_section(ms))
> + return ret;
> +
> + ret = unregister_memory_section(ms);
> +
I saw a patch from Jiang Liu "mm/hotplug: free zone->pageset when a
zone becomes empty" to
free the zone->pageset and i think there may more cleanup needed when
a zone becomes empty.
We already have __add_zone() in __add_section(), what about add a
function like __remove_zone()
to do the cleanup here?
> + return ret;
> }
> #else
> static int __remove_section(struct zone *zone, struct mem_section *ms)
> @@ -346,11 +349,11 @@ EXPORT_SYMBOL_GPL(__add_pages);
> * sure that pages are marked reserved and zones are adjust properly by
> * calling offline_pages().
> */
> -int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
> -unsigned long nr_pages)
> +int __remove_pages(unsigned long phys_start_pfn, unsigned long nr_pages)
> {
> unsigned long i, ret = 0;
> int sections_to_remove;
> + struct zone *zone;
>
> /*
> * We can only remove entire sections
> @@ -363,6 +366,7 @@ int __remove_pages(struct zone *zone, un
> sections_to_remove = nr_pages / PAGES_PER_SECTION;
> for (i = 0; i < sections_to_remove; i++) {
> unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
> + zone = page_zone(pfn_to_page(pfn));
> ret = __remove_section(zone, __pfn_to_section(pfn));
> if (ret)
> break;
> @@ -1031,6 +1035,7 @@ int __ref remove_memory(int nid, u64 sta
> /* remove memmap entry */
> firmware_map_remove(start, start + size, "System RAM");
>
> + __remove_pages(start >> PAGE_SHIFT, size >> PAGE_SHIFT);
> out:
> unlock_memory_hotplug();
> return ret;
> Index: linux-3.5-rc6/include/linux/memory_hotplug.h
> ===
> --- linux-3.5-rc6.orig/include/linux/memory_hotplug.h 2012-07-18
> 18:00:27.445145371 +0900
> +++ linux-3.5-rc6/include/linux/memory_hotplug.h2012-07-18
> 18:00:40.461982690 +0900
> @@ -89,8 +89,7 @@ extern bool is_pageblock_removable_noloc
> /* reasonably generic interface to expand the physical pages in a zone */
> extern int __add_pages(int nid, struct zone *zone, unsigned long start_pfn,
> unsigned long nr_pages);
> -extern int __remove_pages(struct zone *zone, unsigned long start_pfn,
> - unsigned long nr_pages);
> +extern int __remove_pages(unsigned long start_pfn, unsigned long nr_pages);
>
> #ifdef CONFIG_NUMA
> extern int memory_add_physaddr_to_nid(u64 start);
> Index: linux-3.5-rc6/arch/powerpc/platforms/pseries/hotplug-memory.c
> ===
> --- linux-3.5-rc6.orig/arch/powerpc/platforms/pseries/hotplug-memory.c
> 2012-07-18 18:00:27.442145407 +0900
> +++ linux-3.5-rc6/arch/powerpc/platforms/pseries/hotplug-memory.c
> 2012-07-18 18:00:40.470982578 +0900
> @@ -76,7 +76,6 @@ unsigned long memory_block_size_bytes(vo
> static int pseries_remove_memblock(unsigned long base, unsigned int
> memblock_size)
> {
> unsigned long start, start_pfn;
> - struct zone *zone;
> int i, ret;
> int sections_to_remove;
>
> @@ -87,8 +86,6 @@ static int pseries_remove_memblock
Re: [RFC PATCH v4 1/13] memory-hotplug : rename remove_memory to offline_memory
Hi Yasuaki,
On Wed, Jul 18, 2012 at 6:05 PM, Yasuaki Ishimatsu
wrote:
> remove_memory() does not remove memory but just offlines memory. The patch
> changes name of it to offline_memory().
Since offline_memory() just align the start/end pfn and there is no
matched online_memory() function,
i think it's better to remove this function and add the alignment into
offline_pages().
>
> CC: David Rientjes
> CC: Jiang Liu
> CC: Len Brown
> CC: Benjamin Herrenschmidt
> CC: Paul Mackerras
> CC: Christoph Lameter
> Cc: Minchan Kim
> CC: Andrew Morton
> CC: KOSAKI Motohiro
> CC: Wen Congyang
> Signed-off-by: Yasuaki Ishimatsu
>
> ---
> drivers/acpi/acpi_memhotplug.c |2 +-
> drivers/base/memory.c |4 ++--
> include/linux/memory_hotplug.h |2 +-
> mm/memory_hotplug.c|6 +++---
> 4 files changed, 7 insertions(+), 7 deletions(-)
>
> Index: linux-3.5-rc4/drivers/acpi/acpi_memhotplug.c
> ===
> --- linux-3.5-rc4.orig/drivers/acpi/acpi_memhotplug.c 2012-07-03
> 14:21:46.102416917 +0900
> +++ linux-3.5-rc4/drivers/acpi/acpi_memhotplug.c2012-07-03
> 14:21:49.458374960 +0900
> @@ -318,7 +318,7 @@ static int acpi_memory_disable_device(st
> */
> list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
> if (info->enabled) {
> - result = remove_memory(info->start_addr,
> info->length);
> + result = offline_memory(info->start_addr,
> info->length);
> if (result)
> return result;
> }
> Index: linux-3.5-rc4/drivers/base/memory.c
> ===
> --- linux-3.5-rc4.orig/drivers/base/memory.c2012-07-03 14:21:46.095417003
> +0900
> +++ linux-3.5-rc4/drivers/base/memory.c 2012-07-03 14:21:49.459374948 +0900
> @@ -266,8 +266,8 @@ memory_block_action(unsigned long phys_i
> break;
> case MEM_OFFLINE:
> start_paddr = page_to_pfn(first_page) << PAGE_SHIFT;
> - ret = remove_memory(start_paddr,
> - nr_pages << PAGE_SHIFT);
> + ret = offline_memory(start_paddr,
> +nr_pages << PAGE_SHIFT);
> break;
> default:
> WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
> Index: linux-3.5-rc4/mm/memory_hotplug.c
> ===
> --- linux-3.5-rc4.orig/mm/memory_hotplug.c 2012-07-03 14:21:46.102416917
> +0900
> +++ linux-3.5-rc4/mm/memory_hotplug.c 2012-07-03 14:21:49.466374860 +0900
> @@ -990,7 +990,7 @@ out:
> return ret;
> }
>
> -int remove_memory(u64 start, u64 size)
> +int offline_memory(u64 start, u64 size)
> {
> unsigned long start_pfn, end_pfn;
>
> @@ -999,9 +999,9 @@ int remove_memory(u64 start, u64 size)
> return offline_pages(start_pfn, end_pfn, 120 * HZ);
> }
> #else
> -int remove_memory(u64 start, u64 size)
> +int offline_memory(u64 start, u64 size)
> {
> return -EINVAL;
> }
> #endif /* CONFIG_MEMORY_HOTREMOVE */
> -EXPORT_SYMBOL_GPL(remove_memory);
> +EXPORT_SYMBOL_GPL(offline_memory);
> Index: linux-3.5-rc4/include/linux/memory_hotplug.h
> ===
> --- linux-3.5-rc4.orig/include/linux/memory_hotplug.h 2012-07-03
> 14:21:46.102416917 +0900
> +++ linux-3.5-rc4/include/linux/memory_hotplug.h2012-07-03
> 14:21:49.471374796 +0900
> @@ -233,7 +233,7 @@ static inline int is_mem_section_removab
> extern int mem_online_node(int nid);
> extern int add_memory(int nid, u64 start, u64 size);
> extern int arch_add_memory(int nid, u64 start, u64 size);
> -extern int remove_memory(u64 start, u64 size);
> +extern int offline_memory(u64 start, u64 size);
> extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
> int nr_pages);
> extern void sparse_remove_one_section(struct zone *zone, struct mem_section
> *ms);
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majord...@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: mailto:"d...@kvack.org";> em...@kvack.org
--
Regards,
--Bob
___
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
