diff options
Diffstat (limited to 'features/rt/mm-zsmalloc-copy-with-get_cpu_var-and-locking.patch')
| -rw-r--r-- | features/rt/mm-zsmalloc-copy-with-get_cpu_var-and-locking.patch | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/features/rt/mm-zsmalloc-copy-with-get_cpu_var-and-locking.patch b/features/rt/mm-zsmalloc-copy-with-get_cpu_var-and-locking.patch new file mode 100644 index 00000000..20da73a1 --- /dev/null +++ b/features/rt/mm-zsmalloc-copy-with-get_cpu_var-and-locking.patch @@ -0,0 +1,211 @@ +From 58041154aa39fc127b4c5d0f6179c606403ced5d Mon Sep 17 00:00:00 2001 +From: Mike Galbraith <umgwanakikbuti@gmail.com> +Date: Tue, 22 Mar 2016 11:16:09 +0100 +Subject: [PATCH 116/191] mm/zsmalloc: copy with get_cpu_var() and locking + +get_cpu_var() disables preemption and triggers a might_sleep() splat later. +This is replaced with get_locked_var(). +This bitspinlocks are replaced with a proper mutex which requires a slightly +larger struct to allocate. + +Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com> +[bigeasy: replace the bitspin_lock() with a mutex, get_locked_var(). Mike then +fixed the size magic] +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + mm/zsmalloc.c | 85 +++++++++++++++++++++++++++++++++++++++++++++++---- + 1 file changed, 79 insertions(+), 6 deletions(-) + +diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c +index 30c358b72025..6177b736d018 100644 +--- a/mm/zsmalloc.c ++++ b/mm/zsmalloc.c +@@ -57,6 +57,7 @@ + #include <linux/wait.h> + #include <linux/pagemap.h> + #include <linux/fs.h> ++#include <linux/local_lock.h> + + #define ZSPAGE_MAGIC 0x58 + +@@ -77,6 +78,20 @@ + + #define ZS_HANDLE_SIZE (sizeof(unsigned long)) + ++#ifdef CONFIG_PREEMPT_RT ++ ++struct zsmalloc_handle { ++ unsigned long addr; ++ struct mutex lock; ++}; ++ ++#define ZS_HANDLE_ALLOC_SIZE (sizeof(struct zsmalloc_handle)) ++ ++#else ++ ++#define ZS_HANDLE_ALLOC_SIZE (sizeof(unsigned long)) ++#endif ++ + /* + * Object location (<PFN>, <obj_idx>) is encoded as + * a single (unsigned long) handle value. +@@ -293,6 +308,7 @@ struct zspage { + }; + + struct mapping_area { ++ local_lock_t lock; + char *vm_buf; /* copy buffer for objects that span pages */ + char *vm_addr; /* address of kmap_atomic()'ed pages */ + enum zs_mapmode vm_mm; /* mapping mode */ +@@ -322,7 +338,7 @@ static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) {} + + static int create_cache(struct zs_pool *pool) + { +- pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_SIZE, ++ pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_ALLOC_SIZE, + 0, 0, NULL); + if (!pool->handle_cachep) + return 1; +@@ -346,9 +362,26 @@ static void destroy_cache(struct zs_pool *pool) + + static unsigned long cache_alloc_handle(struct zs_pool *pool, gfp_t gfp) + { +- return (unsigned long)kmem_cache_alloc(pool->handle_cachep, +- gfp & ~(__GFP_HIGHMEM|__GFP_MOVABLE)); ++ void *p; ++ ++ p = kmem_cache_alloc(pool->handle_cachep, ++ gfp & ~(__GFP_HIGHMEM|__GFP_MOVABLE)); ++#ifdef CONFIG_PREEMPT_RT ++ if (p) { ++ struct zsmalloc_handle *zh = p; ++ ++ mutex_init(&zh->lock); ++ } ++#endif ++ return (unsigned long)p; ++} ++ ++#ifdef CONFIG_PREEMPT_RT ++static struct zsmalloc_handle *zs_get_pure_handle(unsigned long handle) ++{ ++ return (void *)(handle &~((1 << OBJ_TAG_BITS) - 1)); + } ++#endif + + static void cache_free_handle(struct zs_pool *pool, unsigned long handle) + { +@@ -368,12 +401,18 @@ static void cache_free_zspage(struct zs_pool *pool, struct zspage *zspage) + + static void record_obj(unsigned long handle, unsigned long obj) + { ++#ifdef CONFIG_PREEMPT_RT ++ struct zsmalloc_handle *zh = zs_get_pure_handle(handle); ++ ++ WRITE_ONCE(zh->addr, obj); ++#else + /* + * lsb of @obj represents handle lock while other bits + * represent object value the handle is pointing so + * updating shouldn't do store tearing. + */ + WRITE_ONCE(*(unsigned long *)handle, obj); ++#endif + } + + /* zpool driver */ +@@ -455,7 +494,10 @@ MODULE_ALIAS("zpool-zsmalloc"); + #endif /* CONFIG_ZPOOL */ + + /* per-cpu VM mapping areas for zspage accesses that cross page boundaries */ +-static DEFINE_PER_CPU(struct mapping_area, zs_map_area); ++static DEFINE_PER_CPU(struct mapping_area, zs_map_area) = { ++ /* XXX remove this and use a spin_lock_t in pin_tag() */ ++ .lock = INIT_LOCAL_LOCK(lock), ++}; + + static bool is_zspage_isolated(struct zspage *zspage) + { +@@ -862,7 +904,13 @@ static unsigned long location_to_obj(struct page *page, unsigned int obj_idx) + + static unsigned long handle_to_obj(unsigned long handle) + { ++#ifdef CONFIG_PREEMPT_RT ++ struct zsmalloc_handle *zh = zs_get_pure_handle(handle); ++ ++ return zh->addr; ++#else + return *(unsigned long *)handle; ++#endif + } + + static unsigned long obj_to_head(struct page *page, void *obj) +@@ -876,22 +924,46 @@ static unsigned long obj_to_head(struct page *page, void *obj) + + static inline int testpin_tag(unsigned long handle) + { ++#ifdef CONFIG_PREEMPT_RT ++ struct zsmalloc_handle *zh = zs_get_pure_handle(handle); ++ ++ return mutex_is_locked(&zh->lock); ++#else + return bit_spin_is_locked(HANDLE_PIN_BIT, (unsigned long *)handle); ++#endif + } + + static inline int trypin_tag(unsigned long handle) + { ++#ifdef CONFIG_PREEMPT_RT ++ struct zsmalloc_handle *zh = zs_get_pure_handle(handle); ++ ++ return mutex_trylock(&zh->lock); ++#else + return bit_spin_trylock(HANDLE_PIN_BIT, (unsigned long *)handle); ++#endif + } + + static void pin_tag(unsigned long handle) __acquires(bitlock) + { ++#ifdef CONFIG_PREEMPT_RT ++ struct zsmalloc_handle *zh = zs_get_pure_handle(handle); ++ ++ return mutex_lock(&zh->lock); ++#else + bit_spin_lock(HANDLE_PIN_BIT, (unsigned long *)handle); ++#endif + } + + static void unpin_tag(unsigned long handle) __releases(bitlock) + { ++#ifdef CONFIG_PREEMPT_RT ++ struct zsmalloc_handle *zh = zs_get_pure_handle(handle); ++ ++ return mutex_unlock(&zh->lock); ++#else + bit_spin_unlock(HANDLE_PIN_BIT, (unsigned long *)handle); ++#endif + } + + static void reset_page(struct page *page) +@@ -1274,7 +1346,8 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle, + class = pool->size_class[class_idx]; + off = (class->size * obj_idx) & ~PAGE_MASK; + +- area = &get_cpu_var(zs_map_area); ++ local_lock(&zs_map_area.lock); ++ area = this_cpu_ptr(&zs_map_area); + area->vm_mm = mm; + if (off + class->size <= PAGE_SIZE) { + /* this object is contained entirely within a page */ +@@ -1328,7 +1401,7 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle) + + __zs_unmap_object(area, pages, off, class->size); + } +- put_cpu_var(zs_map_area); ++ local_unlock(&zs_map_area.lock); + + migrate_read_unlock(zspage); + unpin_tag(handle); +-- +2.19.1 + |