From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f194.google.com ([209.85.210.194]:33497 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726580AbfE1MJJ (ORCPT ); Tue, 28 May 2019 08:09:09 -0400 Received: by mail-pf1-f194.google.com with SMTP id z28so11368520pfk.0 for ; Tue, 28 May 2019 05:09:08 -0700 (PDT) From: Nicholas Piggin Subject: [PATCH 4/4] mm/vmalloc: Hugepage vmalloc mappings Date: Tue, 28 May 2019 22:04:53 +1000 Message-Id: <20190528120453.27374-4-npiggin@gmail.com> In-Reply-To: <20190528120453.27374-1-npiggin@gmail.com> References: <20190528120453.27374-1-npiggin@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-mm@kvack.org Cc: Nicholas Piggin , linux-arch@vger.kernel.org, Toshi Kani , Linus Torvalds , Ard Biesheuvel , Andrew Morton , Uladzislau Rezki For platforms that define HAVE_ARCH_HUGE_VMAP, have vmalloc try to allocate and map PMD-level huge pages when size is appropriate, and fallback if unsuccessful. Using 2MB page mappings in an 8MB dentry cache hash brings dTLB misses for linux kernel tree `git diff` from 45,000 to 8,000 on a Kaby Lake CPU wth mitigations=off (performance is in the noise, under 1% difference, page tables are likely to be well cached for this workload). Signed-off-by: Nicholas Piggin --- include/linux/vmalloc.h | 1 + mm/vmalloc.c | 132 +++++++++++++++++++++++++++++++--------- 2 files changed, 105 insertions(+), 28 deletions(-) diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 812bea5866d6..4c92dc608928 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -42,6 +42,7 @@ struct vm_struct { unsigned long size; unsigned long flags; struct page **pages; + unsigned int page_shift; unsigned int nr_pages; phys_addr_t phys_addr; const void *caller; diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 6a0c97f89091..34de925ed4f4 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -36,6 +36,7 @@ #include #include +#include #include #include @@ -439,6 +440,41 @@ static int vmap_pages_range(unsigned long start, unsigned long end, return ret; } +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP +static int vmap_hpages_range(unsigned long start, unsigned long end, + pgprot_t prot, struct page **pages, + unsigned int page_shift) +{ + unsigned long addr = start; + unsigned int i, nr = (end - start) >> (PAGE_SHIFT + page_shift); + + for (i = 0; i < nr; i++) { + int err; + + err = vmap_range_noflush(addr, + addr + (PAGE_SIZE << page_shift), + __pa(page_address(pages[i])), prot, + page_shift); + if (err) + return err; + + addr += PAGE_SIZE << page_shift; + } + flush_cache_vmap(start, end); + + return nr; +} +#else +static int vmap_hpages_range(unsigned long start, unsigned long end, + pgprot_t prot, struct page **pages, + unsigned int page_shift) +{ + BUG_ON(page_shift != PAGE_SIZE); + return vmap_pages_range(start, end, prot, pages); +} +#endif + + int is_vmalloc_or_module_addr(const void *x) { /* @@ -461,7 +497,7 @@ struct page *vmalloc_to_page(const void *vmalloc_addr) { unsigned long addr = (unsigned long) vmalloc_addr; struct page *page = NULL; - pgd_t *pgd = pgd_offset_k(addr); + pgd_t *pgd; p4d_t *p4d; pud_t *pud; pmd_t *pmd; @@ -473,27 +509,38 @@ struct page *vmalloc_to_page(const void *vmalloc_addr) */ VIRTUAL_BUG_ON(!is_vmalloc_or_module_addr(vmalloc_addr)); + pgd = pgd_offset_k(addr); if (pgd_none(*pgd)) return NULL; + p4d = p4d_offset(pgd, addr); if (p4d_none(*p4d)) return NULL; - pud = pud_offset(p4d, addr); +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP + if (p4d_large(*p4d)) + return p4d_page(*p4d) + ((addr & ~P4D_MASK) >> PAGE_SHIFT); +#endif + if (WARN_ON_ONCE(p4d_bad(*p4d))) + return NULL; - /* - * Don't dereference bad PUD or PMD (below) entries. This will also - * identify huge mappings, which we may encounter on architectures - * that define CONFIG_HAVE_ARCH_HUGE_VMAP=y. Such regions will be - * identified as vmalloc addresses by is_vmalloc_addr(), but are - * not [unambiguously] associated with a struct page, so there is - * no correct value to return for them. - */ - WARN_ON_ONCE(pud_bad(*pud)); - if (pud_none(*pud) || pud_bad(*pud)) + pud = pud_offset(p4d, addr); + if (pud_none(*pud)) + return NULL; +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP + if (pud_large(*pud)) + return pud_page(*pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); +#endif + if (WARN_ON_ONCE(pud_bad(*pud))) return NULL; + pmd = pmd_offset(pud, addr); - WARN_ON_ONCE(pmd_bad(*pmd)); - if (pmd_none(*pmd) || pmd_bad(*pmd)) + if (pmd_none(*pmd)) + return NULL; +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP + if (pmd_large(*pmd)) + return pmd_page(*pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); +#endif + if (WARN_ON_ONCE(pmd_bad(*pmd))) return NULL; ptep = pte_offset_map(pmd, addr); @@ -501,6 +548,7 @@ struct page *vmalloc_to_page(const void *vmalloc_addr) if (pte_present(pte)) page = pte_page(pte); pte_unmap(ptep); + return page; } EXPORT_SYMBOL(vmalloc_to_page); @@ -2184,8 +2232,9 @@ static struct vm_struct *__get_vm_area_node(unsigned long size, return NULL; if (flags & VM_IOREMAP) - align = 1ul << clamp_t(int, get_count_order_long(size), - PAGE_SHIFT, IOREMAP_MAX_ORDER); + align = max(align, + 1ul << clamp_t(int, get_count_order_long(size), + PAGE_SHIFT, IOREMAP_MAX_ORDER)); area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node); if (unlikely(!area)) @@ -2397,7 +2446,7 @@ static void __vunmap(const void *addr, int deallocate_pages) struct page *page = area->pages[i]; BUG_ON(!page); - __free_pages(page, 0); + __free_pages(page, area->page_shift); } kvfree(area->pages); @@ -2540,14 +2589,17 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, pgprot_t prot, int node) { struct page **pages; + unsigned long addr = (unsigned long)area->addr; + unsigned long size = get_vm_area_size(area); + unsigned int page_shift = area->page_shift; + unsigned int shift = page_shift + PAGE_SHIFT; unsigned int nr_pages, array_size, i; const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO; const gfp_t alloc_mask = gfp_mask | __GFP_NOWARN; const gfp_t highmem_mask = (gfp_mask & (GFP_DMA | GFP_DMA32)) ? - 0 : - __GFP_HIGHMEM; + 0 : __GFP_HIGHMEM; - nr_pages = get_vm_area_size(area) >> PAGE_SHIFT; + nr_pages = size >> shift; array_size = (nr_pages * sizeof(struct page *)); area->nr_pages = nr_pages; @@ -2568,10 +2620,8 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, for (i = 0; i < area->nr_pages; i++) { struct page *page; - if (node == NUMA_NO_NODE) - page = alloc_page(alloc_mask|highmem_mask); - else - page = alloc_pages_node(node, alloc_mask|highmem_mask, 0); + page = alloc_pages_node(node, + alloc_mask|highmem_mask, page_shift); if (unlikely(!page)) { /* Successfully allocated i pages, free them in __vunmap() */ @@ -2583,8 +2633,9 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, cond_resched(); } - if (map_vm_area(area, prot, pages)) + if (vmap_hpages_range(addr, addr + size, prot, pages, page_shift) < 0) goto fail; + return area->addr; fail: @@ -2618,22 +2669,39 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, pgprot_t prot, unsigned long vm_flags, int node, const void *caller) { - struct vm_struct *area; + struct vm_struct *area = NULL; void *addr; unsigned long real_size = size; + unsigned long real_align = align; + unsigned int shift = PAGE_SHIFT; size = PAGE_ALIGN(size); if (!size || (size >> PAGE_SHIFT) > totalram_pages()) goto fail; + if (IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMAP)) { + unsigned long size_per_node; + + size_per_node = size; + if (node == NUMA_NO_NODE) + size_per_node /= num_online_nodes(); + if (size_per_node >= PMD_SIZE) + shift = PMD_SHIFT; + } +again: + align = max(real_align, 1UL << shift); + size = ALIGN(real_size, align); + area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNINITIALIZED | vm_flags, start, end, node, gfp_mask, caller); if (!area) goto fail; + area->page_shift = shift - PAGE_SHIFT; + addr = __vmalloc_area_node(area, gfp_mask, prot, node); if (!addr) - return NULL; + goto fail; /* * In this function, newly allocated vm_struct has VM_UNINITIALIZED @@ -2647,8 +2715,16 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, return addr; fail: - warn_alloc(gfp_mask, NULL, + if (shift == PMD_SHIFT) { + shift = PAGE_SHIFT; + goto again; + } + + if (!area) { + /* Warn for area allocation, page allocations already warn */ + warn_alloc(gfp_mask, NULL, "vmalloc: allocation failure: %lu bytes", real_size); + } return NULL; } -- 2.20.1