Message ID | d6c06f2ef39bbe6c715b2f6db76eb16155fdcee6.1602722808.git.sudaraja@codeaurora.org (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | [v3] arm64/mm: add fallback option to allocate virtually contiguous memory | expand |
On Wed, Oct 14, 2020 at 05:51:23PM -0700, Sudarshan Rajagopalan wrote: > When section mappings are enabled, we allocate vmemmap pages from > physically continuous memory of size PMD_SIZE using > vmemmap_alloc_block_buf(). Section mappings are good to reduce TLB > pressure. But when system is highly fragmented and memory blocks are > being hot-added at runtime, its possible that such physically continuous > memory allocations can fail. Rather than failing the memory hot-add > procedure, add a fallback option to allocate vmemmap pages from > discontinuous pages using vmemmap_populate_basepages(). > > Signed-off-by: Sudarshan Rajagopalan <sudaraja@codeaurora.org> > Reviewed-by: Gavin Shan <gshan@redhat.com> > Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > Cc: Anshuman Khandual <anshuman.khandual@arm.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Logan Gunthorpe <logang@deltatee.com> > Cc: David Hildenbrand <david@redhat.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Steven Price <steven.price@arm.com> > --- > arch/arm64/mm/mmu.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) Please can you fix the subject? I have three copies of "PATCH v3" from different days in my inbox. I know it sounds trivial, but getting these little things right really helps with review, especially when it's sitting amongst a sea of other patches. Thanks, Will
On 2020-10-15 01:36, Will Deacon wrote: > On Wed, Oct 14, 2020 at 05:51:23PM -0700, Sudarshan Rajagopalan wrote: >> When section mappings are enabled, we allocate vmemmap pages from >> physically continuous memory of size PMD_SIZE using >> vmemmap_alloc_block_buf(). Section mappings are good to reduce TLB >> pressure. But when system is highly fragmented and memory blocks are >> being hot-added at runtime, its possible that such physically >> continuous >> memory allocations can fail. Rather than failing the memory hot-add >> procedure, add a fallback option to allocate vmemmap pages from >> discontinuous pages using vmemmap_populate_basepages(). >> >> Signed-off-by: Sudarshan Rajagopalan <sudaraja@codeaurora.org> >> Reviewed-by: Gavin Shan <gshan@redhat.com> >> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> >> Cc: Catalin Marinas <catalin.marinas@arm.com> >> Cc: Will Deacon <will@kernel.org> >> Cc: Anshuman Khandual <anshuman.khandual@arm.com> >> Cc: Mark Rutland <mark.rutland@arm.com> >> Cc: Logan Gunthorpe <logang@deltatee.com> >> Cc: David Hildenbrand <david@redhat.com> >> Cc: Andrew Morton <akpm@linux-foundation.org> >> Cc: Steven Price <steven.price@arm.com> >> --- >> arch/arm64/mm/mmu.c | 7 +++++-- >> 1 file changed, 5 insertions(+), 2 deletions(-) > > Please can you fix the subject? I have three copies of "PATCH v3" from > different days in my inbox. I know it sounds trivial, but getting these > little things right really helps with review, especially when it's > sitting > amongst a sea of other patches. Yes sure, sorry about that - will change it to "PATCH v4" to make it stand out from other patches. > > Thanks, > > Will Sudarshan -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
On 2020-10-16 11:56, Sudarshan Rajagopalan wrote: Hello Will, Catalin, Did you have a chance to review this patch? It is reviewed by others and haven't seen any Nacks. This patch will be useful to have so that memory hotremove doesn't fail when such PMD_SIZE pages aren't available.. which is usually the case in low RAM devices. > When section mappings are enabled, we allocate vmemmap pages from > physically continuous memory of size PMD_SIZE using > vmemmap_alloc_block_buf(). Section mappings are good to reduce TLB > pressure. But when system is highly fragmented and memory blocks are > being hot-added at runtime, its possible that such physically > continuous > memory allocations can fail. Rather than failing the memory hot-add > procedure, add a fallback option to allocate vmemmap pages from > discontinuous pages using vmemmap_populate_basepages(). > > Signed-off-by: Sudarshan Rajagopalan <sudaraja@codeaurora.org> > Reviewed-by: Gavin Shan <gshan@redhat.com> > Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > Cc: Anshuman Khandual <anshuman.khandual@arm.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Logan Gunthorpe <logang@deltatee.com> > Cc: David Hildenbrand <david@redhat.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Steven Price <steven.price@arm.com> > --- > arch/arm64/mm/mmu.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 75df62fea1b6..44486fd0e883 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -1121,8 +1121,11 @@ int __meminit vmemmap_populate(unsigned long > start, unsigned long end, int node, > void *p = NULL; > > p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap); > - if (!p) > - return -ENOMEM; > + if (!p) { > + if (vmemmap_populate_basepages(addr, next, node, altmap)) > + return -ENOMEM; > + continue; > + } > > pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); > } else
On Fri, Oct 16, 2020 at 11:56:56AM -0700, Sudarshan Rajagopalan wrote: > When section mappings are enabled, we allocate vmemmap pages from > physically continuous memory of size PMD_SIZE using > vmemmap_alloc_block_buf(). Section mappings are good to reduce TLB > pressure. But when system is highly fragmented and memory blocks are > being hot-added at runtime, its possible that such physically continuous > memory allocations can fail. Rather than failing the memory hot-add > procedure, add a fallback option to allocate vmemmap pages from > discontinuous pages using vmemmap_populate_basepages(). > > Signed-off-by: Sudarshan Rajagopalan <sudaraja@codeaurora.org> > Reviewed-by: Gavin Shan <gshan@redhat.com> > Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > Cc: Anshuman Khandual <anshuman.khandual@arm.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Logan Gunthorpe <logang@deltatee.com> > Cc: David Hildenbrand <david@redhat.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Steven Price <steven.price@arm.com> > --- > arch/arm64/mm/mmu.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 75df62fea1b6..44486fd0e883 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -1121,8 +1121,11 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, > void *p = NULL; > > p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap); > - if (!p) > - return -ENOMEM; > + if (!p) { > + if (vmemmap_populate_basepages(addr, next, node, altmap)) > + return -ENOMEM; > + continue; > + } Looks fine to me: Acked-by: Will Deacon <will@kernel.org> Will
On Wed, Nov 04, 2020 at 04:03:36PM -0800, Sudarshan Rajagopalan wrote: > Did you have a chance to review this patch? It is reviewed by others and > haven't seen any Nacks. This patch will be useful to have so that memory > hotremove doesn't fail when such PMD_SIZE pages aren't available.. which is > usually the case in low RAM devices. Can you please post it again please with Will's ack? You posted a v4 which I think had the same message-id as v3. Mutt flagged it as duplicate and I deleted it. Just to be sure (I'll queue it when we get to -rc3). Thanks.
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 75df62fea1b6..44486fd0e883 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1121,8 +1121,11 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, void *p = NULL; p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap); - if (!p) - return -ENOMEM; + if (!p) { + if (vmemmap_populate_basepages(addr, next, node, altmap)) + return -ENOMEM; + continue; + } pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); } else