Le 24/01/2021 à 09:22, Nicholas Piggin a écrit :
Support huge page vmalloc mappings. Config option HAVE_ARCH_HUGE_VMALLOC
enables support on architectures that define HAVE_ARCH_HUGE_VMAP and
supports PMD sized vmap mappings.
vmalloc will attempt to allocate PMD-sized pages if allocating PMD size
or larger, and fall back to small pages if that was unsuccessful.
Architectures must ensure that any arch specific vmalloc allocations
that require PAGE_SIZE mappings (e.g., module allocations vs strict
module rwx) use the VM_NOHUGE flag to inhibit larger mappings.
When hugepage vmalloc mappings are enabled in the next patch, this
reduces TLB misses by nearly 30x on a `git diff` workload on a 2-node
POWER9 (59,800 -> 2,100) and reduces CPU cycles by 0.54%.
This can result in more internal fragmentation and memory overhead for a
given allocation, an option nohugevmalloc is added to disable at boot.
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
arch/Kconfig | 10 +++
include/linux/vmalloc.h | 18 ++++
mm/page_alloc.c | 5 +-
mm/vmalloc.c | 192 ++++++++++++++++++++++++++++++----------
4 files changed, 177 insertions(+), 48 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 0377e1d059e5..eef61e0f5170 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2691,15 +2746,18 @@ EXPORT_SYMBOL_GPL(vmap_pfn);
#endif /* CONFIG_VMAP_PFN */
static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
- pgprot_t prot, int node)
+ pgprot_t prot, unsigned int page_shift,
+ int node)
{
const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
- unsigned int nr_pages = get_vm_area_size(area) >> PAGE_SHIFT;
- unsigned long array_size;
- unsigned int i;
+ unsigned int page_order = page_shift - PAGE_SHIFT;
+ unsigned long addr = (unsigned long)area->addr;
+ unsigned long size = get_vm_area_size(area);
+ unsigned int nr_small_pages = size >> PAGE_SHIFT;
struct page **pages;
+ unsigned int i;
- array_size = (unsigned long)nr_pages * sizeof(struct page *);
+ array_size = (unsigned long)nr_small_pages * sizeof(struct page *);
array_size() is a function in include/linux/overflow.h
For some reason, it breaks the build with your series.
gfp_mask |= __GFP_NOWARN;
if (!(gfp_mask & (GFP_DMA | GFP_DMA32)))
gfp_mask |= __GFP_HIGHMEM;
