[RFC PATCH 14/15] mm: introduce MIN_MAX_ORDER to replace MAX_ORDER as compile time constant.
From: Zi Yan <hidden>
Date: 2021-08-05 19:06:06
Also in:
kvmarm, linux-arm-kernel, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), memory management, memory management - core, memory management - mglru (multi-gen lru), slab allocator, the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Andrew Morton, David Hildenbrand, Vlastimil Babka, Harry Yoo, Linus Torvalds
From: Zi Yan <ziy@nvidia.com> For other MAX_ORDER uses (described below), there is no need or too much hassle to convert certain static array to dynamic ones. Add MIN_MAX_ORDER to serve as compile time constant in place of MAX_ORDER. ARM64 hypervisor maintains its own free page list and does not import any core kernel symbols, so soon-to-be runtime variable MAX_ORDER is not accessible in ARM64 hypervisor code. Also there is no need to allocating very large pages. In SLAB/SLOB/SLUB, 2-D array kmalloc_caches uses MAX_ORDER in its second dimension. It is too much hassle to allocate memory for kmalloc_caches before any proper memory allocator is set up. Signed-off-by: Zi Yan <ziy@nvidia.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Lameter <redacted> Cc: Vlastimil Babka <redacted> Cc: Quentin Perret <redacted> Cc: linux-arm-kernel@lists.infradead.org Cc: kvmarm@lists.cs.columbia.edu Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- arch/arm64/kvm/hyp/include/nvhe/gfp.h | 2 +- arch/arm64/kvm/hyp/nvhe/page_alloc.c | 3 ++- include/linux/mmzone.h | 3 +++ include/linux/slab.h | 8 ++++---- mm/slab.c | 2 +- mm/slub.c | 7 ++++--- 6 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/arch/arm64/kvm/hyp/include/nvhe/gfp.h b/arch/arm64/kvm/hyp/include/nvhe/gfp.h
index fb0f523d1492..c774b4a98336 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/gfp.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/gfp.h@@ -16,7 +16,7 @@ struct hyp_pool { * API at EL2. */ hyp_spinlock_t lock; - struct list_head free_area[MAX_ORDER]; + struct list_head free_area[MIN_MAX_ORDER]; phys_addr_t range_start; phys_addr_t range_end; unsigned short max_order;
diff --git a/arch/arm64/kvm/hyp/nvhe/page_alloc.c b/arch/arm64/kvm/hyp/nvhe/page_alloc.c
index 41fc25bdfb34..a1cc1b648de0 100644
--- a/arch/arm64/kvm/hyp/nvhe/page_alloc.c
+++ b/arch/arm64/kvm/hyp/nvhe/page_alloc.c@@ -226,7 +226,8 @@ int hyp_pool_init(struct hyp_pool *pool, u64 pfn, unsigned int nr_pages, int i; hyp_spin_lock_init(&pool->lock); - pool->max_order = min(MAX_ORDER, get_order(nr_pages << PAGE_SHIFT)); + + pool->max_order = min(MIN_MAX_ORDER, get_order(nr_pages << PAGE_SHIFT)); for (i = 0; i < pool->max_order; i++) INIT_LIST_HEAD(&pool->free_area[i]); pool->range_start = phys;
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 09aafc05aef4..379dada82d4b 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h@@ -27,11 +27,14 @@ #ifndef CONFIG_ARCH_FORCE_MAX_ORDER #ifdef CONFIG_SET_MAX_ORDER #define MAX_ORDER CONFIG_SET_MAX_ORDER +#define MIN_MAX_ORDER CONFIG_SET_MAX_ORDER #else #define MAX_ORDER 11 +#define MIN_MAX_ORDER MAX_ORDER #endif /* CONFIG_SET_MAX_ORDER */ #else #define MAX_ORDER CONFIG_ARCH_FORCE_MAX_ORDER +#define MIN_MAX_ORDER CONFIG_ARCH_FORCE_MAX_ORDER #endif /* CONFIG_ARCH_FORCE_MAX_ORDER */ #define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1))
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 2c0d80cca6b8..d8747c158db6 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h@@ -244,8 +244,8 @@ static inline void __check_heap_object(const void *ptr, unsigned long n, * to do various tricks to work around compiler limitations in order to * ensure proper constant folding. */ -#define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \ - (MAX_ORDER + PAGE_SHIFT - 1) : 25) +#define KMALLOC_SHIFT_HIGH ((MIN_MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \ + (MIN_MAX_ORDER + PAGE_SHIFT - 1) : 25) #define KMALLOC_SHIFT_MAX KMALLOC_SHIFT_HIGH #ifndef KMALLOC_SHIFT_LOW #define KMALLOC_SHIFT_LOW 5
@@ -258,7 +258,7 @@ static inline void __check_heap_object(const void *ptr, unsigned long n, * (PAGE_SIZE*2). Larger requests are passed to the page allocator. */ #define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1) -#define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT - 1) +#define KMALLOC_SHIFT_MAX (MIN_MAX_ORDER + PAGE_SHIFT - 1) #ifndef KMALLOC_SHIFT_LOW #define KMALLOC_SHIFT_LOW 3 #endif
@@ -271,7 +271,7 @@ static inline void __check_heap_object(const void *ptr, unsigned long n, * be allocated from the same page. */ #define KMALLOC_SHIFT_HIGH PAGE_SHIFT -#define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT - 1) +#define KMALLOC_SHIFT_MAX (MIN_MAX_ORDER + PAGE_SHIFT - 1) #ifndef KMALLOC_SHIFT_LOW #define KMALLOC_SHIFT_LOW 3 #endif
diff --git a/mm/slab.c b/mm/slab.c
index d0f725637663..0041de8ec0e9 100644
--- a/mm/slab.c
+++ b/mm/slab.c@@ -466,7 +466,7 @@ static int __init slab_max_order_setup(char *str) { get_option(&str, &slab_max_order); slab_max_order = slab_max_order < 0 ? 0 : - min(slab_max_order, MAX_ORDER - 1); + min(slab_max_order, MIN_MAX_ORDER - 1); slab_max_order_set = true; return 1;
diff --git a/mm/slub.c b/mm/slub.c
index b6c5205252eb..228e4a77c678 100644
--- a/mm/slub.c
+++ b/mm/slub.c@@ -3564,8 +3564,9 @@ static inline int calculate_order(unsigned int size) /* * Doh this slab cannot be placed using slub_max_order. */ - order = slab_order(size, 1, MAX_ORDER, 1); - if (order < MAX_ORDER) + + order = slab_order(size, 1, MIN_MAX_ORDER, 1); + if (order < MIN_MAX_ORDER) return order; return -ENOSYS; }
@@ -4079,7 +4080,7 @@ __setup("slub_min_order=", setup_slub_min_order); static int __init setup_slub_max_order(char *str) { get_option(&str, (int *)&slub_max_order); - slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER - 1); + slub_max_order = min(slub_max_order, (unsigned int)MIN_MAX_ORDER - 1); return 1; }
--
2.30.2