| Message ID | 20210430143607.135005-3-leobras.c@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | powerpc/mm/hash: Time improvements for memory hot(un)plug | expand |
| Related | show |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (e3a9b9d6a03f5fbf99b540e863b001d46ba1735c) |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 61 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
On Fri, Apr 30, 2021 at 11:36:08AM -0300, Leonardo Bras wrote: > Every time a memory hotplug happens, and the memory limit crosses a 2^n > value, it may be necessary to perform HPT resizing-up, which can take > some time (over 100ms in my tests). > > It usually is not an issue, but it can take some time if a lot of memory > is added to a guest with little starting memory: > Adding 256G to a 2GB guest, for example will require 8 HPT resizes. > > Perform an HPT resize before memory hotplug, updating HPT to its > final size (considering a successful hotplug), taking the number of > HPT resizes to at most one per memory hotplug action. > > Signed-off-by: Leonardo Bras <leobras.c@gmail.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> > --- > arch/powerpc/include/asm/book3s/64/hash.h | 2 ++ > arch/powerpc/mm/book3s64/hash_utils.c | 20 +++++++++++++++++++ > .../platforms/pseries/hotplug-memory.c | 9 +++++++++ > 3 files changed, 31 insertions(+) > > diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h > index d959b0195ad9..fad4af8b8543 100644 > --- a/arch/powerpc/include/asm/book3s/64/hash.h > +++ b/arch/powerpc/include/asm/book3s/64/hash.h > @@ -255,6 +255,8 @@ int hash__create_section_mapping(unsigned long start, unsigned long end, > int nid, pgprot_t prot); > int hash__remove_section_mapping(unsigned long start, unsigned long end); > > +void hash_batch_expand_prepare(unsigned long newsize); > + > #endif /* !__ASSEMBLY__ */ > #endif /* __KERNEL__ */ > #endif /* _ASM_POWERPC_BOOK3S_64_HASH_H */ > diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c > index 608e4ed397a9..3fa395b3fe57 100644 > --- a/arch/powerpc/mm/book3s64/hash_utils.c > +++ b/arch/powerpc/mm/book3s64/hash_utils.c > @@ -859,6 +859,26 @@ int hash__remove_section_mapping(unsigned long start, unsigned long end) > > return rc; > } > + > +void hash_batch_expand_prepare(unsigned long newsize) > +{ > + const u64 starting_size = ppc64_pft_size; > + > + /* > + * Resizing-up HPT should never fail, but there are some cases system starts with higher > + * SHIFT than required, and we go through the funny case of resizing HPT down while > + * adding memory > + */ > + > + while (resize_hpt_for_hotplug(newsize, false) == -ENOSPC) { > + newsize *= 2; > + pr_warn("Hash collision while resizing HPT\n"); > + > + /* Do not try to resize to the starting size, or bigger value */ > + if (htab_shift_for_mem_size(newsize) >= starting_size) > + break; > + } > +} > #endif /* CONFIG_MEMORY_HOTPLUG */ > > static void __init hash_init_partition_table(phys_addr_t hash_table, > diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c > index 8377f1f7c78e..48b2cfe4ce69 100644 > --- a/arch/powerpc/platforms/pseries/hotplug-memory.c > +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c > @@ -13,6 +13,7 @@ > #include <linux/memory.h> > #include <linux/memory_hotplug.h> > #include <linux/slab.h> > +#include <linux/pgtable.h> > > #include <asm/firmware.h> > #include <asm/machdep.h> > @@ -671,6 +672,10 @@ static int dlpar_memory_add_by_count(u32 lmbs_to_add) > if (lmbs_available < lmbs_to_add) > return -EINVAL; > > + if (!radix_enabled()) > + hash_batch_expand_prepare(memblock_phys_mem_size() + > + lmbs_to_add * drmem_lmb_size()); > + > for_each_drmem_lmb(lmb) { > if (lmb->flags & DRCONF_MEM_ASSIGNED) > continue; > @@ -788,6 +793,10 @@ static int dlpar_memory_add_by_ic(u32 lmbs_to_add, u32 drc_index) > if (lmbs_available < lmbs_to_add) > return -EINVAL; > > + if (!radix_enabled()) > + hash_batch_expand_prepare(memblock_phys_mem_size() + > + lmbs_to_add * drmem_lmb_size()); > + > for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) { > if (lmb->flags & DRCONF_MEM_ASSIGNED) > continue;
On Mon, 2021-06-07 at 15:10 +1000, David Gibson wrote: > On Fri, Apr 30, 2021 at 11:36:08AM -0300, Leonardo Bras wrote: > > Every time a memory hotplug happens, and the memory limit crosses a > > 2^n > > value, it may be necessary to perform HPT resizing-up, which can > > take > > some time (over 100ms in my tests). > > > > It usually is not an issue, but it can take some time if a lot of > > memory > > is added to a guest with little starting memory: > > Adding 256G to a 2GB guest, for example will require 8 HPT resizes. > > > > Perform an HPT resize before memory hotplug, updating HPT to its > > final size (considering a successful hotplug), taking the number of > > HPT resizes to at most one per memory hotplug action. > > > > Signed-off-by: Leonardo Bras <leobras.c@gmail.com> > > Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Thanks David! > > > --- > > arch/powerpc/include/asm/book3s/64/hash.h | 2 ++ > > arch/powerpc/mm/book3s64/hash_utils.c | 20 > > +++++++++++++++++++ > > .../platforms/pseries/hotplug-memory.c | 9 +++++++++ > > 3 files changed, 31 insertions(+) > > > > diff --git a/arch/powerpc/include/asm/book3s/64/hash.h > > b/arch/powerpc/include/asm/book3s/64/hash.h > > index d959b0195ad9..fad4af8b8543 100644 > > --- a/arch/powerpc/include/asm/book3s/64/hash.h > > +++ b/arch/powerpc/include/asm/book3s/64/hash.h > > @@ -255,6 +255,8 @@ int hash__create_section_mapping(unsigned long > > start, unsigned long end, > > int nid, pgprot_t prot); > > int hash__remove_section_mapping(unsigned long start, unsigned > > long end); > > > > +void hash_batch_expand_prepare(unsigned long newsize); > > + > > #endif /* !__ASSEMBLY__ */ > > #endif /* __KERNEL__ */ > > #endif /* _ASM_POWERPC_BOOK3S_64_HASH_H */ > > diff --git a/arch/powerpc/mm/book3s64/hash_utils.c > > b/arch/powerpc/mm/book3s64/hash_utils.c > > index 608e4ed397a9..3fa395b3fe57 100644 > > --- a/arch/powerpc/mm/book3s64/hash_utils.c > > +++ b/arch/powerpc/mm/book3s64/hash_utils.c > > @@ -859,6 +859,26 @@ int hash__remove_section_mapping(unsigned long > > start, unsigned long end) > > > > return rc; > > } > > + > > +void hash_batch_expand_prepare(unsigned long newsize) > > +{ > > + const u64 starting_size = ppc64_pft_size; > > + > > + /* > > + * Resizing-up HPT should never fail, but there are some > > cases system starts with higher > > + * SHIFT than required, and we go through the funny case of > > resizing HPT down while > > + * adding memory > > + */ > > + > > + while (resize_hpt_for_hotplug(newsize, false) == -ENOSPC) { > > + newsize *= 2; > > + pr_warn("Hash collision while resizing HPT\n"); > > + > > + /* Do not try to resize to the starting size, or > > bigger value */ > > + if (htab_shift_for_mem_size(newsize) >= > > starting_size) > > + break; > > + } > > +} > > #endif /* CONFIG_MEMORY_HOTPLUG */ > > > > static void __init hash_init_partition_table(phys_addr_t > > hash_table, > > diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c > > b/arch/powerpc/platforms/pseries/hotplug-memory.c > > index 8377f1f7c78e..48b2cfe4ce69 100644 > > --- a/arch/powerpc/platforms/pseries/hotplug-memory.c > > +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c > > @@ -13,6 +13,7 @@ > > #include <linux/memory.h> > > #include <linux/memory_hotplug.h> > > #include <linux/slab.h> > > +#include <linux/pgtable.h> > > > > #include <asm/firmware.h> > > #include <asm/machdep.h> > > @@ -671,6 +672,10 @@ static int dlpar_memory_add_by_count(u32 > > lmbs_to_add) > > if (lmbs_available < lmbs_to_add) > > return -EINVAL; > > > > + if (!radix_enabled()) > > + hash_batch_expand_prepare(memblock_phys_mem_size() > > + > > + lmbs_to_add * > > drmem_lmb_size()); > > + > > for_each_drmem_lmb(lmb) { > > if (lmb->flags & DRCONF_MEM_ASSIGNED) > > continue; > > @@ -788,6 +793,10 @@ static int dlpar_memory_add_by_ic(u32 > > lmbs_to_add, u32 drc_index) > > if (lmbs_available < lmbs_to_add) > > return -EINVAL; > > > > + if (!radix_enabled()) > > + hash_batch_expand_prepare(memblock_phys_mem_size() > > + > > + lmbs_to_add * > > drmem_lmb_size()); > > + > > for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) { > > if (lmb->flags & DRCONF_MEM_ASSIGNED) > > continue; > > -- > David Gibson | I'll have my music baroque, and my > code > david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ > _other_ > | _way_ _around_! > http://www.ozlabs.org/~dgibson
diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h index d959b0195ad9..fad4af8b8543 100644 --- a/arch/powerpc/include/asm/book3s/64/hash.h +++ b/arch/powerpc/include/asm/book3s/64/hash.h @@ -255,6 +255,8 @@ int hash__create_section_mapping(unsigned long start, unsigned long end, int nid, pgprot_t prot); int hash__remove_section_mapping(unsigned long start, unsigned long end); +void hash_batch_expand_prepare(unsigned long newsize); + #endif /* !__ASSEMBLY__ */ #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_BOOK3S_64_HASH_H */ diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index 608e4ed397a9..3fa395b3fe57 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -859,6 +859,26 @@ int hash__remove_section_mapping(unsigned long start, unsigned long end) return rc; } + +void hash_batch_expand_prepare(unsigned long newsize) +{ + const u64 starting_size = ppc64_pft_size; + + /* + * Resizing-up HPT should never fail, but there are some cases system starts with higher + * SHIFT than required, and we go through the funny case of resizing HPT down while + * adding memory + */ + + while (resize_hpt_for_hotplug(newsize, false) == -ENOSPC) { + newsize *= 2; + pr_warn("Hash collision while resizing HPT\n"); + + /* Do not try to resize to the starting size, or bigger value */ + if (htab_shift_for_mem_size(newsize) >= starting_size) + break; + } +} #endif /* CONFIG_MEMORY_HOTPLUG */ static void __init hash_init_partition_table(phys_addr_t hash_table, diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c index 8377f1f7c78e..48b2cfe4ce69 100644 --- a/arch/powerpc/platforms/pseries/hotplug-memory.c +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c @@ -13,6 +13,7 @@ #include <linux/memory.h> #include <linux/memory_hotplug.h> #include <linux/slab.h> +#include <linux/pgtable.h> #include <asm/firmware.h> #include <asm/machdep.h> @@ -671,6 +672,10 @@ static int dlpar_memory_add_by_count(u32 lmbs_to_add) if (lmbs_available < lmbs_to_add) return -EINVAL; + if (!radix_enabled()) + hash_batch_expand_prepare(memblock_phys_mem_size() + + lmbs_to_add * drmem_lmb_size()); + for_each_drmem_lmb(lmb) { if (lmb->flags & DRCONF_MEM_ASSIGNED) continue; @@ -788,6 +793,10 @@ static int dlpar_memory_add_by_ic(u32 lmbs_to_add, u32 drc_index) if (lmbs_available < lmbs_to_add) return -EINVAL; + if (!radix_enabled()) + hash_batch_expand_prepare(memblock_phys_mem_size() + + lmbs_to_add * drmem_lmb_size()); + for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) { if (lmb->flags & DRCONF_MEM_ASSIGNED) continue;
Every time a memory hotplug happens, and the memory limit crosses a 2^n value, it may be necessary to perform HPT resizing-up, which can take some time (over 100ms in my tests). It usually is not an issue, but it can take some time if a lot of memory is added to a guest with little starting memory: Adding 256G to a 2GB guest, for example will require 8 HPT resizes. Perform an HPT resize before memory hotplug, updating HPT to its final size (considering a successful hotplug), taking the number of HPT resizes to at most one per memory hotplug action. Signed-off-by: Leonardo Bras <leobras.c@gmail.com> --- arch/powerpc/include/asm/book3s/64/hash.h | 2 ++ arch/powerpc/mm/book3s64/hash_utils.c | 20 +++++++++++++++++++ .../platforms/pseries/hotplug-memory.c | 9 +++++++++ 3 files changed, 31 insertions(+)