| Message ID | 1561697083-7329-2-git-send-email-anshuman.khandual@arm.com (mailing list archive) |
|---|---|
| State | RFC |
| Headers | show |
| Series | arm64: Enable vmemmap from device memory | expand |
On Fri, Jun 28, 2019 at 10:14:42AM +0530, Anshuman Khandual wrote: > Generic vmemmap_populate_basepages() is used across platforms for vmemmap > as standard or as fallback when huge pages mapping fails. On arm64 it is > used for configs with ARM64_SWAPPER_USES_SECTION_MAPS applicable both for > ARM64_16K_PAGES and ARM64_64K_PAGES which cannot use huge pages because of > alignment requirements. > > This prevents those configs from allocating from device memory for vmemap > mapping as vmemmap_populate_basepages() does not support vmem_altmap. This > enables that required support. Each architecture should evaluate and decide > on enabling device based base page allocation when appropriate. Hence this > keeps it disabled for all architectures to preserve the existing semantics. This commit message doesn't really make sense to me. There's a huge amount of arm64-specific detail, followed by vague references to "this" and "those" and "that" and I lost track of what you're trying to solve. However, I puzzled through the code and I think it does make sense, so: Acked-by: Will Deacon <will@kernel.org> assuming you rewrite the commit message. However, this has a dependency on your hot remove series which has open comments from Mark Rutland afaict. Will
On 07/31/2019 09:40 PM, Will Deacon wrote: > On Fri, Jun 28, 2019 at 10:14:42AM +0530, Anshuman Khandual wrote: >> Generic vmemmap_populate_basepages() is used across platforms for vmemmap >> as standard or as fallback when huge pages mapping fails. On arm64 it is >> used for configs with ARM64_SWAPPER_USES_SECTION_MAPS applicable both for >> ARM64_16K_PAGES and ARM64_64K_PAGES which cannot use huge pages because of >> alignment requirements. >> >> This prevents those configs from allocating from device memory for vmemap >> mapping as vmemmap_populate_basepages() does not support vmem_altmap. This >> enables that required support. Each architecture should evaluate and decide >> on enabling device based base page allocation when appropriate. Hence this >> keeps it disabled for all architectures to preserve the existing semantics. > > This commit message doesn't really make sense to me. There's a huge amount > of arm64-specific detail, followed by vague references to "this" and > "those" and "that" and I lost track of what you're trying to solve. Hmm, will clean up. > > However, I puzzled through the code and I think it does make sense, so: > > Acked-by: Will Deacon <will@kernel.org> > > assuming you rewrite the commit message. Thanks, will do. > > However, this has a dependency on your hot remove series which has open > comments from Mark Rutland afaict. Yeah it has dependency on the hot-remove series. The only outstanding issue there being whether to call free_empty_tables() in vmemmap tear down path or not. Mark had asked for more details regarding the implications in cases where free_empty_tables() is called or is not called. I did evaluate those details recently and we should be able to take a decision sooner.
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 194c84e..39e18d1 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -982,7 +982,7 @@ static void remove_pagetable(unsigned long start, unsigned long end, int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, struct vmem_altmap *altmap) { - return vmemmap_populate_basepages(start, end, node); + return vmemmap_populate_basepages(start, end, node, NULL); } #else /* !ARM64_SWAPPER_USES_SECTION_MAPS */ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c index 05490dd..faefd7e 100644 --- a/arch/ia64/mm/discontig.c +++ b/arch/ia64/mm/discontig.c @@ -660,7 +660,7 @@ void arch_refresh_nodedata(int update_node, pg_data_t *update_pgdat) int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, struct vmem_altmap *altmap) { - return vmemmap_populate_basepages(start, end, node); + return vmemmap_populate_basepages(start, end, node, NULL); } void vmemmap_free(unsigned long start, unsigned long end, diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 8335ac6..c67ad5d 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1509,7 +1509,7 @@ static int __meminit vmemmap_populate_hugepages(unsigned long start, vmemmap_verify((pte_t *)pmd, node, addr, next); continue; } - if (vmemmap_populate_basepages(addr, next, node)) + if (vmemmap_populate_basepages(addr, next, node, NULL)) return -ENOMEM; } return 0; @@ -1527,7 +1527,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, __func__); err = -ENOMEM; } else - err = vmemmap_populate_basepages(start, end, node); + err = vmemmap_populate_basepages(start, end, node, NULL); if (!err) sync_global_pgds(start, end - 1); return err; diff --git a/include/linux/mm.h b/include/linux/mm.h index c6ae9eb..dda9bd4 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2758,14 +2758,15 @@ pgd_t *vmemmap_pgd_populate(unsigned long addr, int node); p4d_t *vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node); pud_t *vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node); pmd_t *vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node); -pte_t *vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node); +pte_t *vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node, + struct vmem_altmap *altmap); void *vmemmap_alloc_block(unsigned long size, int node); struct vmem_altmap; void *vmemmap_alloc_block_buf(unsigned long size, int node); void *altmap_alloc_block_buf(unsigned long size, struct vmem_altmap *altmap); void vmemmap_verify(pte_t *, int, unsigned long, unsigned long); int vmemmap_populate_basepages(unsigned long start, unsigned long end, - int node); + int node, struct vmem_altmap *altmap); int vmemmap_populate(unsigned long start, unsigned long end, int node, struct vmem_altmap *altmap); void vmemmap_populate_print_last(void); diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c index 7fec057..d333b75 100644 --- a/mm/sparse-vmemmap.c +++ b/mm/sparse-vmemmap.c @@ -140,12 +140,18 @@ void __meminit vmemmap_verify(pte_t *pte, int node, start, end - 1); } -pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node) +pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node, + struct vmem_altmap *altmap) { pte_t *pte = pte_offset_kernel(pmd, addr); if (pte_none(*pte)) { pte_t entry; - void *p = vmemmap_alloc_block_buf(PAGE_SIZE, node); + void *p; + + if (altmap) + p = altmap_alloc_block_buf(PAGE_SIZE, altmap); + else + p = vmemmap_alloc_block_buf(PAGE_SIZE, node); if (!p) return NULL; entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL); @@ -213,8 +219,8 @@ pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node) return pgd; } -int __meminit vmemmap_populate_basepages(unsigned long start, - unsigned long end, int node) +int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end, + int node, struct vmem_altmap *altmap) { unsigned long addr = start; pgd_t *pgd; @@ -236,7 +242,7 @@ int __meminit vmemmap_populate_basepages(unsigned long start, pmd = vmemmap_pmd_populate(pud, addr, node); if (!pmd) return -ENOMEM; - pte = vmemmap_pte_populate(pmd, addr, node); + pte = vmemmap_pte_populate(pmd, addr, node, altmap); if (!pte) return -ENOMEM; vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
Generic vmemmap_populate_basepages() is used across platforms for vmemmap as standard or as fallback when huge pages mapping fails. On arm64 it is used for configs with ARM64_SWAPPER_USES_SECTION_MAPS applicable both for ARM64_16K_PAGES and ARM64_64K_PAGES which cannot use huge pages because of alignment requirements. This prevents those configs from allocating from device memory for vmemap mapping as vmemmap_populate_basepages() does not support vmem_altmap. This enables that required support. Each architecture should evaluate and decide on enabling device based base page allocation when appropriate. Hence this keeps it disabled for all architectures to preserve the existing semantics. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-ia64@vger.kernel.org Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> --- arch/arm64/mm/mmu.c | 2 +- arch/ia64/mm/discontig.c | 2 +- arch/x86/mm/init_64.c | 4 ++-- include/linux/mm.h | 5 +++-- mm/sparse-vmemmap.c | 16 +++++++++++----- 5 files changed, 18 insertions(+), 11 deletions(-)