| Message ID | 20240411160526.2093408-3-rppt@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86/module: use large ROX pages for text allocations | expand |
Le 11/04/2024 à 18:05, Mike Rapoport a écrit : > From: "Mike Rapoport (IBM)" <rppt@kernel.org> > > vmalloc allocations with VM_ALLOW_HUGE_VMAP that do not explictly > specify node ID will use huge pages only if size_per_node is larger than > PMD_SIZE. > Still the actual allocated memory is not distributed between nodes and > there is no advantage in such approach. > On the contrary, BPF allocates PMD_SIZE * num_possible_nodes() for each > new bpf_prog_pack, while it could do with PMD_SIZE'ed packs. > > Don't account for number of nodes for VM_ALLOW_HUGE_VMAP with > NUMA_NO_NODE and use huge pages whenever the requested allocation size > is larger than PMD_SIZE. Patch looks ok but message is confusing. We also use huge pages at PTE size, for instance 512k pages or 16k pages on powerpc 8xx, while PMD_SIZE is 4M. Christophe > > Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org> > --- > mm/vmalloc.c | 9 ++------- > 1 file changed, 2 insertions(+), 7 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 22aa63f4ef63..5fc8b514e457 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -3737,8 +3737,6 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, > } > > if (vmap_allow_huge && (vm_flags & VM_ALLOW_HUGE_VMAP)) { > - unsigned long size_per_node; > - > /* > * Try huge pages. Only try for PAGE_KERNEL allocations, > * others like modules don't yet expect huge pages in > @@ -3746,13 +3744,10 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, > * supporting them. > */ > > - size_per_node = size; > - if (node == NUMA_NO_NODE) > - size_per_node /= num_online_nodes(); > - if (arch_vmap_pmd_supported(prot) && size_per_node >= PMD_SIZE) > + if (arch_vmap_pmd_supported(prot) && size >= PMD_SIZE) > shift = PMD_SHIFT; > else > - shift = arch_vmap_pte_supported_shift(size_per_node); > + shift = arch_vmap_pte_supported_shift(size); > > align = max(real_align, 1UL << shift); > size = ALIGN(real_size, 1UL << shift);
On Fri, Apr 12, 2024 at 06:07:19AM +0000, Christophe Leroy wrote: > > > Le 11/04/2024 à 18:05, Mike Rapoport a écrit : > > From: "Mike Rapoport (IBM)" <rppt@kernel.org> > > > > vmalloc allocations with VM_ALLOW_HUGE_VMAP that do not explictly > > specify node ID will use huge pages only if size_per_node is larger than > > PMD_SIZE. > > Still the actual allocated memory is not distributed between nodes and > > there is no advantage in such approach. > > On the contrary, BPF allocates PMD_SIZE * num_possible_nodes() for each > > new bpf_prog_pack, while it could do with PMD_SIZE'ed packs. > > > > Don't account for number of nodes for VM_ALLOW_HUGE_VMAP with > > NUMA_NO_NODE and use huge pages whenever the requested allocation size > > is larger than PMD_SIZE. > > Patch looks ok but message is confusing. We also use huge pages at PTE > size, for instance 512k pages or 16k pages on powerpc 8xx, while > PMD_SIZE is 4M. Ok, I'll rephrase. > Christophe > > > > > Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org> > > --- > > mm/vmalloc.c | 9 ++------- > > 1 file changed, 2 insertions(+), 7 deletions(-) > > > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > > index 22aa63f4ef63..5fc8b514e457 100644 > > --- a/mm/vmalloc.c > > +++ b/mm/vmalloc.c > > @@ -3737,8 +3737,6 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, > > } > > > > if (vmap_allow_huge && (vm_flags & VM_ALLOW_HUGE_VMAP)) { > > - unsigned long size_per_node; > > - > > /* > > * Try huge pages. Only try for PAGE_KERNEL allocations, > > * others like modules don't yet expect huge pages in > > @@ -3746,13 +3744,10 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, > > * supporting them. > > */ > > > > - size_per_node = size; > > - if (node == NUMA_NO_NODE) > > - size_per_node /= num_online_nodes(); > > - if (arch_vmap_pmd_supported(prot) && size_per_node >= PMD_SIZE) > > + if (arch_vmap_pmd_supported(prot) && size >= PMD_SIZE) > > shift = PMD_SHIFT; > > else > > - shift = arch_vmap_pte_supported_shift(size_per_node); > > + shift = arch_vmap_pte_supported_shift(size); > > > > align = max(real_align, 1UL << shift); > > size = ALIGN(real_size, 1UL << shift);
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 22aa63f4ef63..5fc8b514e457 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -3737,8 +3737,6 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, } if (vmap_allow_huge && (vm_flags & VM_ALLOW_HUGE_VMAP)) { - unsigned long size_per_node; - /* * Try huge pages. Only try for PAGE_KERNEL allocations, * others like modules don't yet expect huge pages in @@ -3746,13 +3744,10 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, * supporting them. */ - size_per_node = size; - if (node == NUMA_NO_NODE) - size_per_node /= num_online_nodes(); - if (arch_vmap_pmd_supported(prot) && size_per_node >= PMD_SIZE) + if (arch_vmap_pmd_supported(prot) && size >= PMD_SIZE) shift = PMD_SHIFT; else - shift = arch_vmap_pte_supported_shift(size_per_node); + shift = arch_vmap_pte_supported_shift(size); align = max(real_align, 1UL << shift); size = ALIGN(real_size, 1UL << shift);