| Message ID | 1454045043-25545-5-git-send-email-david@gibson.dropbear.id.au (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On 01/29/2016 10:53 AM, David Gibson wrote: > This makes a number of cleanups to handling of mapping failures during > memory hotplug on Power: > > For errors creating the linear mapping for the hot-added region: > * This is now reported with EFAULT which is more appropriate than the > previous EINVAL (the failure is unlikely to be related to the > function's parameters) > * An error in this path now prints a warning message, rather than just > silently failing to add the extra memory. > * Previously a failure here could result in the region being partially > mapped. We now clean up any partial mapping before failing. > > For errors creating the vmemmap for the hot-added region: > * This is now reported with EFAULT instead of causing a BUG() - this > could happen for external reason (e.g. full hash table) so it's better > to handle this non-fatally > * An error message is also printed, so the failure won't be silent > * As above a failure could cause a partially mapped region, we now > clean this up. Yeah this greatly improves graceful fall back when when memory mapping failure happens at the last level during memory hotplug.
On 01/28/2016 11:23 PM, David Gibson wrote: > This makes a number of cleanups to handling of mapping failures during > memory hotplug on Power: > > For errors creating the linear mapping for the hot-added region: > * This is now reported with EFAULT which is more appropriate than the > previous EINVAL (the failure is unlikely to be related to the > function's parameters) > * An error in this path now prints a warning message, rather than just > silently failing to add the extra memory. > * Previously a failure here could result in the region being partially > mapped. We now clean up any partial mapping before failing. > > For errors creating the vmemmap for the hot-added region: > * This is now reported with EFAULT instead of causing a BUG() - this > could happen for external reason (e.g. full hash table) so it's better > to handle this non-fatally > * An error message is also printed, so the failure won't be silent > * As above a failure could cause a partially mapped region, we now > clean this up. > > Signed-off-by: David Gibson <david@gibson.dropbear.id.au> > --- > arch/powerpc/mm/hash_utils_64.c | 13 ++++++++++--- > arch/powerpc/mm/init_64.c | 38 ++++++++++++++++++++++++++------------ > arch/powerpc/mm/mem.c | 10 ++++++++-- > 3 files changed, 44 insertions(+), 17 deletions(-) > > diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c > index 0737eae..e88a86e 100644 > --- a/arch/powerpc/mm/hash_utils_64.c > +++ b/arch/powerpc/mm/hash_utils_64.c > @@ -635,9 +635,16 @@ static unsigned long __init htab_get_table_size(void) > #ifdef CONFIG_MEMORY_HOTPLUG > int create_section_mapping(unsigned long start, unsigned long end) > { > - return htab_bolt_mapping(start, end, __pa(start), > - pgprot_val(PAGE_KERNEL), mmu_linear_psize, > - mmu_kernel_ssize); > + int rc = htab_bolt_mapping(start, end, __pa(start), > + pgprot_val(PAGE_KERNEL), mmu_linear_psize, > + mmu_kernel_ssize); > + > + if (rc < 0) { > + int rc2 = htab_remove_mapping(start, end, mmu_linear_psize, > + mmu_kernel_ssize); > + BUG_ON(rc2 && (rc2 != -ENOENT)); > + } > + return rc; > } > <-- snip --> > #ifdef CONFIG_MEMORY_HOTPLUG > @@ -217,15 +219,20 @@ static void vmemmap_remove_mapping(unsigned long start, > } > #endif > #else /* CONFIG_PPC_BOOK3E */ > -static void __meminit vmemmap_create_mapping(unsigned long start, > - unsigned long page_size, > - unsigned long phys) > +static int __meminit vmemmap_create_mapping(unsigned long start, > + unsigned long page_size, > + unsigned long phys) > { > - int mapped = htab_bolt_mapping(start, start + page_size, phys, > - pgprot_val(PAGE_KERNEL), > - mmu_vmemmap_psize, > - mmu_kernel_ssize); > - BUG_ON(mapped < 0); > + int rc = htab_bolt_mapping(start, start + page_size, phys, > + pgprot_val(PAGE_KERNEL), > + mmu_vmemmap_psize, mmu_kernel_ssize); > + if (rc < 0) { > + int rc2 = htab_remove_mapping(start, start + page_size, > + mmu_vmemmap_psize, > + mmu_kernel_ssize); > + BUG_ON(rc2 && (rc2 != -ENOENT)); > + } > + return rc; > } > If I'm reading this correctly it appears that create_section_mapping() and vmemmap_create_mapping() for !PPC_BOOK3E are identical. Any reason to not have one routine, perhaps just have vmemmap_create_mapping() just call create_section_mapping()? -Nathan
On Tue, Feb 02, 2016 at 09:04:23AM -0600, Nathan Fontenot wrote: > On 01/28/2016 11:23 PM, David Gibson wrote: > > This makes a number of cleanups to handling of mapping failures during > > memory hotplug on Power: > > > > For errors creating the linear mapping for the hot-added region: > > * This is now reported with EFAULT which is more appropriate than the > > previous EINVAL (the failure is unlikely to be related to the > > function's parameters) > > * An error in this path now prints a warning message, rather than just > > silently failing to add the extra memory. > > * Previously a failure here could result in the region being partially > > mapped. We now clean up any partial mapping before failing. > > > > For errors creating the vmemmap for the hot-added region: > > * This is now reported with EFAULT instead of causing a BUG() - this > > could happen for external reason (e.g. full hash table) so it's better > > to handle this non-fatally > > * An error message is also printed, so the failure won't be silent > > * As above a failure could cause a partially mapped region, we now > > clean this up. > > > > Signed-off-by: David Gibson <david@gibson.dropbear.id.au> > > --- > > arch/powerpc/mm/hash_utils_64.c | 13 ++++++++++--- > > arch/powerpc/mm/init_64.c | 38 ++++++++++++++++++++++++++------------ > > arch/powerpc/mm/mem.c | 10 ++++++++-- > > 3 files changed, 44 insertions(+), 17 deletions(-) > > > > diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c > > index 0737eae..e88a86e 100644 > > --- a/arch/powerpc/mm/hash_utils_64.c > > +++ b/arch/powerpc/mm/hash_utils_64.c > > @@ -635,9 +635,16 @@ static unsigned long __init htab_get_table_size(void) > > #ifdef CONFIG_MEMORY_HOTPLUG > > int create_section_mapping(unsigned long start, unsigned long end) > > { > > - return htab_bolt_mapping(start, end, __pa(start), > > - pgprot_val(PAGE_KERNEL), mmu_linear_psize, > > - mmu_kernel_ssize); > > + int rc = htab_bolt_mapping(start, end, __pa(start), > > + pgprot_val(PAGE_KERNEL), mmu_linear_psize, > > + mmu_kernel_ssize); > > + > > + if (rc < 0) { > > + int rc2 = htab_remove_mapping(start, end, mmu_linear_psize, > > + mmu_kernel_ssize); > > + BUG_ON(rc2 && (rc2 != -ENOENT)); > > + } > > + return rc; > > } > > > > <-- snip --> > > > #ifdef CONFIG_MEMORY_HOTPLUG > > @@ -217,15 +219,20 @@ static void vmemmap_remove_mapping(unsigned long start, > > } > > #endif > > #else /* CONFIG_PPC_BOOK3E */ > > -static void __meminit vmemmap_create_mapping(unsigned long start, > > - unsigned long page_size, > > - unsigned long phys) > > +static int __meminit vmemmap_create_mapping(unsigned long start, > > + unsigned long page_size, > > + unsigned long phys) > > { > > - int mapped = htab_bolt_mapping(start, start + page_size, phys, > > - pgprot_val(PAGE_KERNEL), > > - mmu_vmemmap_psize, > > - mmu_kernel_ssize); > > - BUG_ON(mapped < 0); > > + int rc = htab_bolt_mapping(start, start + page_size, phys, > > + pgprot_val(PAGE_KERNEL), > > + mmu_vmemmap_psize, mmu_kernel_ssize); > > + if (rc < 0) { > > + int rc2 = htab_remove_mapping(start, start + page_size, > > + mmu_vmemmap_psize, > > + mmu_kernel_ssize); > > + BUG_ON(rc2 && (rc2 != -ENOENT)); > > + } > > + return rc; > > } > > > > If I'm reading this correctly it appears that create_section_mapping() and > vmemmap_create_mapping() for !PPC_BOOK3E are identical. Any reason to not > have one routine, perhaps just have vmemmap_create_mapping() just call > create_section_mapping()? Not really, apart from documenting what they're used for. They're both fairly trivial wrappers around htab_bolt_mapping(). I think cleaning this up is outside the scope of this series though.
On Fri, Jan 29, 2016 at 04:23:58PM +1100, David Gibson wrote: > This makes a number of cleanups to handling of mapping failures during > memory hotplug on Power: > > For errors creating the linear mapping for the hot-added region: > * This is now reported with EFAULT which is more appropriate than the > previous EINVAL (the failure is unlikely to be related to the > function's parameters) > * An error in this path now prints a warning message, rather than just > silently failing to add the extra memory. > * Previously a failure here could result in the region being partially > mapped. We now clean up any partial mapping before failing. > > For errors creating the vmemmap for the hot-added region: > * This is now reported with EFAULT instead of causing a BUG() - this > could happen for external reason (e.g. full hash table) so it's better > to handle this non-fatally > * An error message is also printed, so the failure won't be silent > * As above a failure could cause a partially mapped region, we now > clean this up. > > Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index 0737eae..e88a86e 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -635,9 +635,16 @@ static unsigned long __init htab_get_table_size(void) #ifdef CONFIG_MEMORY_HOTPLUG int create_section_mapping(unsigned long start, unsigned long end) { - return htab_bolt_mapping(start, end, __pa(start), - pgprot_val(PAGE_KERNEL), mmu_linear_psize, - mmu_kernel_ssize); + int rc = htab_bolt_mapping(start, end, __pa(start), + pgprot_val(PAGE_KERNEL), mmu_linear_psize, + mmu_kernel_ssize); + + if (rc < 0) { + int rc2 = htab_remove_mapping(start, end, mmu_linear_psize, + mmu_kernel_ssize); + BUG_ON(rc2 && (rc2 != -ENOENT)); + } + return rc; } int remove_section_mapping(unsigned long start, unsigned long end) diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c index baa1a23..fbc9448 100644 --- a/arch/powerpc/mm/init_64.c +++ b/arch/powerpc/mm/init_64.c @@ -188,9 +188,9 @@ static int __meminit vmemmap_populated(unsigned long start, int page_size) */ #ifdef CONFIG_PPC_BOOK3E -static void __meminit vmemmap_create_mapping(unsigned long start, - unsigned long page_size, - unsigned long phys) +static int __meminit vmemmap_create_mapping(unsigned long start, + unsigned long page_size, + unsigned long phys) { /* Create a PTE encoding without page size */ unsigned long i, flags = _PAGE_PRESENT | _PAGE_ACCESSED | @@ -208,6 +208,8 @@ static void __meminit vmemmap_create_mapping(unsigned long start, */ for (i = 0; i < page_size; i += PAGE_SIZE) BUG_ON(map_kernel_page(start + i, phys, flags)); + + return 0; } #ifdef CONFIG_MEMORY_HOTPLUG @@ -217,15 +219,20 @@ static void vmemmap_remove_mapping(unsigned long start, } #endif #else /* CONFIG_PPC_BOOK3E */ -static void __meminit vmemmap_create_mapping(unsigned long start, - unsigned long page_size, - unsigned long phys) +static int __meminit vmemmap_create_mapping(unsigned long start, + unsigned long page_size, + unsigned long phys) { - int mapped = htab_bolt_mapping(start, start + page_size, phys, - pgprot_val(PAGE_KERNEL), - mmu_vmemmap_psize, - mmu_kernel_ssize); - BUG_ON(mapped < 0); + int rc = htab_bolt_mapping(start, start + page_size, phys, + pgprot_val(PAGE_KERNEL), + mmu_vmemmap_psize, mmu_kernel_ssize); + if (rc < 0) { + int rc2 = htab_remove_mapping(start, start + page_size, + mmu_vmemmap_psize, + mmu_kernel_ssize); + BUG_ON(rc2 && (rc2 != -ENOENT)); + } + return rc; } #ifdef CONFIG_MEMORY_HOTPLUG @@ -304,6 +311,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node) for (; start < end; start += page_size) { void *p; + int rc; if (vmemmap_populated(start, page_size)) continue; @@ -317,7 +325,13 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node) pr_debug(" * %016lx..%016lx allocated at %p\n", start, start + page_size, p); - vmemmap_create_mapping(start, page_size, __pa(p)); + rc = vmemmap_create_mapping(start, page_size, __pa(p)); + if (rc < 0) { + pr_warning( + "vmemmap_populate: Unable to create vmemmap mapping: %d\n", + rc); + return -EFAULT; + } } return 0; diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 22d94c3..8ffc1e2 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -119,12 +119,18 @@ int arch_add_memory(int nid, u64 start, u64 size, bool for_device) struct zone *zone; unsigned long start_pfn = start >> PAGE_SHIFT; unsigned long nr_pages = size >> PAGE_SHIFT; + int rc; pgdata = NODE_DATA(nid); start = (unsigned long)__va(start); - if (create_section_mapping(start, start + size)) - return -EINVAL; + rc = create_section_mapping(start, start + size); + if (rc) { + pr_warning( + "Unable to create mapping for hot added memory 0x%llx..0x%llx: %d\n", + start, start + size, rc); + return -EFAULT; + } /* this should work for most non-highmem platforms */ zone = pgdata->node_zones +
This makes a number of cleanups to handling of mapping failures during memory hotplug on Power: For errors creating the linear mapping for the hot-added region: * This is now reported with EFAULT which is more appropriate than the previous EINVAL (the failure is unlikely to be related to the function's parameters) * An error in this path now prints a warning message, rather than just silently failing to add the extra memory. * Previously a failure here could result in the region being partially mapped. We now clean up any partial mapping before failing. For errors creating the vmemmap for the hot-added region: * This is now reported with EFAULT instead of causing a BUG() - this could happen for external reason (e.g. full hash table) so it's better to handle this non-fatally * An error message is also printed, so the failure won't be silent * As above a failure could cause a partially mapped region, we now clean this up. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> --- arch/powerpc/mm/hash_utils_64.c | 13 ++++++++++--- arch/powerpc/mm/init_64.c | 38 ++++++++++++++++++++++++++------------ arch/powerpc/mm/mem.c | 10 ++++++++-- 3 files changed, 44 insertions(+), 17 deletions(-)