powerpc/kvm: Use 256K chunk to track both RMA and hash page table allocation.
Both RMA and hash page table request will be a multiple of 256K. We can use a chunk size of 256K to track the free/used 256K chunk in the bitmap. This should help to reduce the bitmap size. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
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@ -37,6 +37,8 @@
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#include <asm/ppc-opcode.h>
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#include <asm/cputable.h>
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#include "book3s_hv_cma.h"
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/* POWER7 has 10-bit LPIDs, PPC970 has 6-bit LPIDs */
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#define MAX_LPID_970 63
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@ -71,6 +73,7 @@ long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp)
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/* Next try to allocate from the preallocated pool */
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if (!hpt) {
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VM_BUG_ON(order < KVM_CMA_CHUNK_ORDER);
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page = kvm_alloc_hpt(1 << (order - PAGE_SHIFT));
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if (page) {
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hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page));
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@ -24,6 +24,8 @@
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#include <linux/sizes.h>
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#include <linux/slab.h>
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#include "book3s_hv_cma.h"
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struct kvm_cma {
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unsigned long base_pfn;
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unsigned long count;
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@ -96,6 +98,7 @@ struct page *kvm_alloc_cma(unsigned long nr_pages, unsigned long align_pages)
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int ret;
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struct page *page = NULL;
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struct kvm_cma *cma = &kvm_cma_area;
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unsigned long chunk_count, nr_chunk;
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unsigned long mask, pfn, pageno, start = 0;
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@ -107,21 +110,27 @@ struct page *kvm_alloc_cma(unsigned long nr_pages, unsigned long align_pages)
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if (!nr_pages)
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return NULL;
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/*
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* align mask with chunk size. The bit tracks pages in chunk size
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*/
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VM_BUG_ON(!is_power_of_2(align_pages));
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mask = align_pages - 1;
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mask = (align_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT)) - 1;
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BUILD_BUG_ON(PAGE_SHIFT > KVM_CMA_CHUNK_ORDER);
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chunk_count = cma->count >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
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nr_chunk = nr_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
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mutex_lock(&kvm_cma_mutex);
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for (;;) {
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pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
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start, nr_pages, mask);
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if (pageno >= cma->count)
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pageno = bitmap_find_next_zero_area(cma->bitmap, chunk_count,
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start, nr_chunk, mask);
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if (pageno >= chunk_count)
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break;
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pfn = cma->base_pfn + pageno;
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pfn = cma->base_pfn + (pageno << (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT));
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ret = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_CMA);
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if (ret == 0) {
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bitmap_set(cma->bitmap, pageno, nr_pages);
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bitmap_set(cma->bitmap, pageno, nr_chunk);
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page = pfn_to_page(pfn);
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memset(pfn_to_kaddr(pfn), 0, nr_pages << PAGE_SHIFT);
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break;
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@ -150,9 +159,9 @@ struct page *kvm_alloc_cma(unsigned long nr_pages, unsigned long align_pages)
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bool kvm_release_cma(struct page *pages, unsigned long nr_pages)
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{
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unsigned long pfn;
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unsigned long nr_chunk;
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struct kvm_cma *cma = &kvm_cma_area;
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if (!cma || !pages)
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return false;
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@ -164,9 +173,12 @@ bool kvm_release_cma(struct page *pages, unsigned long nr_pages)
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return false;
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VM_BUG_ON(pfn + nr_pages > cma->base_pfn + cma->count);
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nr_chunk = nr_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
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mutex_lock(&kvm_cma_mutex);
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bitmap_clear(cma->bitmap, pfn - cma->base_pfn, nr_pages);
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bitmap_clear(cma->bitmap,
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(pfn - cma->base_pfn) >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT),
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nr_chunk);
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free_contig_range(pfn, nr_pages);
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mutex_unlock(&kvm_cma_mutex);
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@ -204,13 +216,14 @@ static int __init kvm_cma_activate_area(unsigned long base_pfn,
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static int __init kvm_cma_init_reserved_areas(void)
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{
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int bitmap_size, ret;
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unsigned long chunk_count;
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struct kvm_cma *cma = &kvm_cma_area;
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pr_debug("%s()\n", __func__);
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if (!cma->count)
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return 0;
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bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
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chunk_count = cma->count >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
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bitmap_size = BITS_TO_LONGS(chunk_count) * sizeof(long);
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cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
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if (!cma->bitmap)
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return -ENOMEM;
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@ -14,6 +14,11 @@
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#ifndef __POWERPC_KVM_CMA_ALLOC_H__
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#define __POWERPC_KVM_CMA_ALLOC_H__
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/*
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* Both RMA and Hash page allocation will be multiple of 256K.
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*/
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#define KVM_CMA_CHUNK_ORDER 18
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extern struct page *kvm_alloc_cma(unsigned long nr_pages,
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unsigned long align_pages);
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extern bool kvm_release_cma(struct page *pages, unsigned long nr_pages);
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