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[193.116.100.32]) by smtp.gmail.com with ESMTPSA id l17sm21863475pff.126.2020.08.09.19.28.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 09 Aug 2020 19:28:31 -0700 (PDT) From: Nicholas Piggin To: linux-mm@kvack.org Cc: Nicholas Piggin , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Zefan Li Subject: [PATCH v3 8/8] mm/vmalloc: Hugepage vmalloc mappings Date: Mon, 10 Aug 2020 12:27:32 +1000 Message-Id: <20200810022732.1150009-9-npiggin@gmail.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20200810022732.1150009-1-npiggin@gmail.com> References: <20200810022732.1150009-1-npiggin@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On platforms that define HAVE_ARCH_HUGE_VMAP and support PMD vmaps, vmalloc will attempt to allocate PMD-sized pages first, before falling back to small pages. Allocations which use something other than PAGE_KERNEL protections are not permitted to use huge pages yet, not all callers expect this (e.g., module allocations vs strict module rwx). 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 nohugevmap is added to disable at boot. Signed-off-by: Nicholas Piggin --- .../admin-guide/kernel-parameters.txt | 2 + include/linux/vmalloc.h | 1 + mm/vmalloc.c | 174 +++++++++++++----- 3 files changed, 135 insertions(+), 42 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 98ea67f27809..eaef176c597f 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3190,6 +3190,8 @@ nohugeiomap [KNL,x86,PPC] Disable kernel huge I/O mappings. + nohugevmap [KNL,x86,PPC] Disable kernel huge vmalloc mappings. + nosmt [KNL,S390] Disable symmetric multithreading (SMT). Equivalent to smt=1. diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index e3590e93bfff..8f25dbaca0a1 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -58,6 +58,7 @@ struct vm_struct { unsigned long size; unsigned long flags; struct page **pages; + unsigned int page_order; unsigned int nr_pages; phys_addr_t phys_addr; const void *caller; diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 4e5cb7c7f780..a7728c7086bc 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -45,6 +45,19 @@ #include "internal.h" #include "pgalloc-track.h" +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP +static bool __ro_after_init vmap_allow_huge = true; + +static int __init set_nohugevmap(char *str) +{ + vmap_allow_huge = false; + return 0; +} +early_param("nohugevmap", set_nohugevmap); +#else /* CONFIG_HAVE_ARCH_HUGE_VMAP */ +static const bool vmap_allow_huge = false; +#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */ + bool is_vmalloc_addr(const void *x) { unsigned long addr = (unsigned long)x; @@ -468,31 +481,12 @@ static int vmap_pages_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long en return 0; } -/** - * map_kernel_range_noflush - map kernel VM area with the specified pages - * @addr: start of the VM area to map - * @size: size of the VM area to map - * @prot: page protection flags to use - * @pages: pages to map - * - * Map PFN_UP(@size) pages at @addr. The VM area @addr and @size specify should - * have been allocated using get_vm_area() and its friends. - * - * NOTE: - * This function does NOT do any cache flushing. The caller is responsible for - * calling flush_cache_vmap() on to-be-mapped areas before calling this - * function. - * - * RETURNS: - * 0 on success, -errno on failure. - */ -int map_kernel_range_noflush(unsigned long addr, unsigned long size, - pgprot_t prot, struct page **pages) +static int vmap_small_pages_range_noflush(unsigned long addr, unsigned long end, + pgprot_t prot, struct page **pages) { unsigned long start = addr; - unsigned long end = addr + size; - unsigned long next; pgd_t *pgd; + unsigned long next; int err = 0; int nr = 0; pgtbl_mod_mask mask = 0; @@ -514,6 +508,65 @@ int map_kernel_range_noflush(unsigned long addr, unsigned long size, return 0; } +static int vmap_pages_range_noflush(unsigned long addr, unsigned long end, + pgprot_t prot, struct page **pages, unsigned int page_shift) +{ + WARN_ON(page_shift < PAGE_SHIFT); + + if (page_shift == PAGE_SHIFT) { + return vmap_small_pages_range_noflush(addr, end, prot, pages); + } else { + unsigned int i, nr = (end - addr) >> page_shift; + + for (i = 0; i < nr; i++) { + int err; + + err = vmap_range_noflush(addr, addr + (1UL << page_shift), + __pa(page_address(pages[i])), prot, page_shift); + if (err) + return err; + + addr += 1UL << page_shift; + } + + return 0; + } +} + +static int vmap_pages_range(unsigned long addr, unsigned long end, + pgprot_t prot, struct page **pages, unsigned int page_shift) +{ + int err; + + err = vmap_pages_range_noflush(addr, end, prot, pages, page_shift); + flush_cache_vmap(addr, end); + return err; +} + +/** + * map_kernel_range_noflush - map kernel VM area with the specified pages + * @addr: start of the VM area to map + * @size: size of the VM area to map + * @prot: page protection flags to use + * @pages: pages to map + * + * Map PFN_UP(@size) pages at @addr. The VM area @addr and @size specify should + * have been allocated using get_vm_area() and its friends. + * + * NOTE: + * This function does NOT do any cache flushing. The caller is responsible for + * calling flush_cache_vmap() on to-be-mapped areas before calling this + * function. + * + * RETURNS: + * 0 on success, -errno on failure. + */ +int map_kernel_range_noflush(unsigned long addr, unsigned long size, + pgprot_t prot, struct page **pages) +{ + return vmap_pages_range_noflush(addr, addr + size, prot, pages, PAGE_SHIFT); +} + int map_kernel_range(unsigned long start, unsigned long size, pgprot_t prot, struct page **pages) { @@ -2274,9 +2327,11 @@ static struct vm_struct *__get_vm_area_node(unsigned long size, if (unlikely(!size)) return NULL; - if (flags & VM_IOREMAP) - align = 1ul << clamp_t(int, get_count_order_long(size), - PAGE_SHIFT, IOREMAP_MAX_ORDER); + if (flags & VM_IOREMAP) { + 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)) @@ -2475,7 +2530,8 @@ 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_order); + i += 1 << area->page_order; } atomic_long_sub(area->nr_pages, &nr_vmalloc_pages); @@ -2614,9 +2670,12 @@ void *vmap(struct page **pages, unsigned int count, EXPORT_SYMBOL(vmap); 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) { struct page **pages; + unsigned long addr = (unsigned long)area->addr; + unsigned long size = get_vm_area_size(area); + unsigned int page_order = 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; @@ -2624,7 +2683,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, 0 : __GFP_HIGHMEM; - nr_pages = get_vm_area_size(area) >> PAGE_SHIFT; + nr_pages = size >> PAGE_SHIFT; array_size = (nr_pages * sizeof(struct page *)); /* Please note that the recursion is strictly bounded. */ @@ -2643,29 +2702,29 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, area->pages = pages; area->nr_pages = nr_pages; + area->page_order = page_order; - for (i = 0; i < area->nr_pages; i++) { + for (i = 0; i < area->nr_pages; i += 1 << page_order) { struct page *page; + int p; - 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_order); if (unlikely(!page)) { /* Successfully allocated i pages, free them in __vunmap() */ area->nr_pages = i; atomic_long_add(area->nr_pages, &nr_vmalloc_pages); goto fail; } - area->pages[i] = page; + + for (p = 0; p < (1 << page_order); p++) + area->pages[i + p] = page + p; + if (gfpflags_allow_blocking(gfp_mask)) cond_resched(); } atomic_long_add(area->nr_pages, &nr_vmalloc_pages); - if (map_kernel_range((unsigned long)area->addr, get_vm_area_size(area), - prot, pages) < 0) + if (vmap_pages_range(addr, addr + size, prot, pages, page_shift) < 0) goto fail; return area->addr; @@ -2701,22 +2760,45 @@ 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; - area = __get_vm_area_node(real_size, align, VM_ALLOC | VM_UNINITIALIZED | + if (vmap_allow_huge && (pgprot_val(prot) == pgprot_val(PAGE_KERNEL))) { + unsigned long size_per_node; + + /* + * Try huge pages. Only try for PAGE_KERNEL allocations, + * others like modules don't yet expect huge pages in + * their allocations due to apply_to_page_range not + * supporting them. + */ + + 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; - addr = __vmalloc_area_node(area, gfp_mask, prot, node); + addr = __vmalloc_area_node(area, gfp_mask, prot, shift, node); if (!addr) - return NULL; + goto fail; /* * In this function, newly allocated vm_struct has VM_UNINITIALIZED @@ -2730,8 +2812,16 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, return addr; fail: - warn_alloc(gfp_mask, NULL, + if (shift > PAGE_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; } -- 2.23.0