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kmem_cache hardening and performance improvements
- Added slab work queue task which gradually ages and free's slabs from the cache which have not been used recently. - Optimized slab packing algorithm to ensure each slab contains the maximum number of objects without create to large a slab. - Fix deadlock, we can never call kv_free() under the skc_lock. We now unlink the objects and slabs from the cache itself and attach them to a private work list. The contents of the list are then subsequently freed outside the spin lock. - Move magazine create/destroy operation on to local cpu. - Further performace optimizations by minimize the usage of the large per-cache skc_lock. This includes the addition of KMC_BIT_REAPING bit mask which is used to prevent concurrent reaping, and to defer new slab creation when reaping is occuring. - Add KMC_BIT_DESTROYING bit mask which is set when the cache is being destroyed, this is used to catch any task accessing the cache while it is being destroyed. - Add comments to all the functions and additional comments to try and make everything as clear as possible. - Major cleanup and additions to the SPLAT kmem tests to more rigerously stress the cache implementation and look for any problems. This includes correctness and performance tests. - Updated portable work queue interfaces
This commit is contained in:
Brian Behlendorf
parent
34e71c9e97
commit
ea3e6ca9e5
@ -45,6 +45,7 @@ extern "C" {
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#include <asm/atomic_compat.h>
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#include <sys/types.h>
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#include <sys/debug.h>
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#include <sys/workqueue.h>
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/*
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* Memory allocation interfaces
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@ -161,17 +162,32 @@ kmem_alloc_tryhard(size_t size, size_t *alloc_size, int kmflags)
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/*
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* Slab allocation interfaces
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*/
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#define KMC_NOTOUCH 0x00000001
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#define KMC_NODEBUG 0x00000002 /* Default behavior */
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#define KMC_NOMAGAZINE 0x00000004 /* XXX: No disable support available */
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#define KMC_NOHASH 0x00000008 /* XXX: No hash available */
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#define KMC_QCACHE 0x00000010 /* XXX: Unsupported */
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#define KMC_KMEM 0x00000100 /* Use kmem cache */
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#define KMC_VMEM 0x00000200 /* Use vmem cache */
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#define KMC_OFFSLAB 0x00000400 /* Objects not on slab */
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enum {
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KMC_BIT_NOTOUCH = 0, /* Don't update ages */
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KMC_BIT_NODEBUG = 1, /* Default behavior */
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KMC_BIT_NOMAGAZINE = 2, /* XXX: Unsupported */
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KMC_BIT_NOHASH = 3, /* XXX: Unsupported */
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KMC_BIT_QCACHE = 4, /* XXX: Unsupported */
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KMC_BIT_KMEM = 5, /* Use kmem cache */
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KMC_BIT_VMEM = 6, /* Use vmem cache */
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KMC_BIT_OFFSLAB = 7, /* Objects not on slab */
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KMC_BIT_REAPING = 16, /* Reaping in progress */
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KMC_BIT_DESTROY = 17, /* Destroy in progress */
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};
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#define KMC_REAP_CHUNK 256
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#define KMC_DEFAULT_SEEKS DEFAULT_SEEKS
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#define KMC_NOTOUCH (1 << KMC_BIT_NOTOUCH)
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#define KMC_NODEBUG (1 << KMC_BIT_NODEBUG)
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#define KMC_NOMAGAZINE (1 << KMC_BIT_NOMAGAZINE)
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#define KMC_NOHASH (1 << KMC_BIT_NOHASH)
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#define KMC_QCACHE (1 << KMC_BIT_QCACHE)
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#define KMC_KMEM (1 << KMC_BIT_KMEM)
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#define KMC_VMEM (1 << KMC_BIT_VMEM)
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#define KMC_OFFSLAB (1 << KMC_BIT_OFFSLAB)
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#define KMC_REAPING (1 << KMC_BIT_REAPING)
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#define KMC_DESTROY (1 << KMC_BIT_DESTROY)
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#define KMC_REAP_CHUNK INT_MAX
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#define KMC_DEFAULT_SEEKS 1
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#ifdef DEBUG_KMEM_UNIMPLEMENTED
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static __inline__ void kmem_init(void) {
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@ -223,9 +239,10 @@ extern struct rw_semaphore spl_kmem_cache_sem;
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#define SKS_MAGIC 0x22222222
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#define SKC_MAGIC 0x2c2c2c2c
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#define SPL_KMEM_CACHE_DELAY 5
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#define SPL_KMEM_CACHE_OBJ_PER_SLAB 32
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#define SPL_KMEM_CACHE_ALIGN 8
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#define SPL_KMEM_CACHE_DELAY 5 /* Minimum slab release age */
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#define SPL_KMEM_CACHE_OBJ_PER_SLAB 32 /* Target objects per slab */
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#define SPL_KMEM_CACHE_OBJ_PER_SLAB_MIN 8 /* Minimum objects per slab */
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#define SPL_KMEM_CACHE_ALIGN 8 /* Default object alignment */
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typedef int (*spl_kmem_ctor_t)(void *, void *, int);
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typedef void (*spl_kmem_dtor_t)(void *, void *);
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@ -274,7 +291,11 @@ typedef struct spl_kmem_cache {
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uint32_t skc_obj_align; /* Object alignment */
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uint32_t skc_slab_objs; /* Objects per slab */
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uint32_t skc_slab_size; /* Slab size */
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uint32_t skc_delay; /* slab reclaim interval */
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uint32_t skc_delay; /* Slab reclaim interval */
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atomic_t skc_ref; /* Ref count callers */
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struct delayed_work skc_work; /* Slab reclaim work */
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struct work_struct work;
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struct timer_list timer;
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struct list_head skc_list; /* List of caches linkage */
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struct list_head skc_complete_list;/* Completely alloc'ed */
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struct list_head skc_partial_list; /* Partially alloc'ed */
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@ -203,18 +203,6 @@ extern int ddi_strtoul(const char *str, char **nptr,
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#define offsetof(s, m) ((size_t)(&(((s *)0)->m)))
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#endif
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#ifdef HAVE_3ARGS_INIT_WORK
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#define spl_init_work(wq,cb,d) INIT_WORK((wq), (void *)(cb), (void *)(d))
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#define spl_get_work_data(type,field,data) (data)
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#else
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#define spl_init_work(wq,cb,d) INIT_WORK((wq), (void *)(cb));
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#define spl_get_work_data(type,field,data) container_of(data,type,field)
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#endif
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#ifdef __cplusplus
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}
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#endif
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@ -35,8 +35,7 @@
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extern vmem_t *zio_alloc_arena; /* arena for zio caches */
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#define physmem num_physpages
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#define freemem nr_free_pages() // Expensive on linux,
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// cheap on solaris
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#define freemem nr_free_pages()
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#define minfree 0
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#define needfree 0 /* # of needed pages */
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#define ptob(pages) (pages * PAGE_SIZE)
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@ -132,10 +132,6 @@ EXPORT_SYMBOL(kmem_set_warning);
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* small virtual address space on 32bit arches. This will seriously
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* constrain the size of the slab caches and their performance.
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*
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* XXX: Implement work requests to keep an eye on each cache and
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* shrink them via spl_slab_reclaim() when they are wasting lots
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* of space. Currently this process is driven by the reapers.
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*
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* XXX: Improve the partial slab list by carefully maintaining a
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* strict ordering of fullest to emptiest slabs based on
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* the slab reference count. This gaurentees the when freeing
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@ -571,7 +567,8 @@ kv_free(spl_kmem_cache_t *skc, void *ptr, int size)
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}
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}
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/* It's important that we pack the spl_kmem_obj_t structure and the
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/*
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* It's important that we pack the spl_kmem_obj_t structure and the
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* actual objects in to one large address space to minimize the number
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* of calls to the allocator. It is far better to do a few large
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* allocations and then subdivide it ourselves. Now which allocator
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@ -662,14 +659,17 @@ out:
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RETURN(sks);
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}
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/* Removes slab from complete or partial list, so it must
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* be called with the 'skc->skc_lock' held.
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/*
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* Remove a slab from complete or partial list, it must be called with
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* the 'skc->skc_lock' held but the actual free must be performed
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* outside the lock to prevent deadlocking on vmem addresses.
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*/
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static void
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spl_slab_free(spl_kmem_slab_t *sks) {
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spl_slab_free(spl_kmem_slab_t *sks,
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struct list_head *sks_list, struct list_head *sko_list)
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{
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spl_kmem_cache_t *skc;
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spl_kmem_obj_t *sko, *n;
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int size;
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ENTRY;
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ASSERT(sks->sks_magic == SKS_MAGIC);
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@ -682,114 +682,190 @@ spl_slab_free(spl_kmem_slab_t *sks) {
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skc->skc_obj_total -= sks->sks_objs;
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skc->skc_slab_total--;
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list_del(&sks->sks_list);
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size = P2ROUNDUP(skc->skc_obj_size, skc->skc_obj_align) +
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P2ROUNDUP(sizeof(spl_kmem_obj_t), skc->skc_obj_align);
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/* Run destructors slab is being released */
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list_for_each_entry_safe(sko, n, &sks->sks_free_list, sko_list) {
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ASSERT(sko->sko_magic == SKO_MAGIC);
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list_del(&sko->sko_list);
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if (skc->skc_dtor)
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skc->skc_dtor(sko->sko_addr, skc->skc_private);
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if (skc->skc_flags & KMC_OFFSLAB)
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kv_free(skc, sko->sko_addr, size);
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list_add(&sko->sko_list, sko_list);
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}
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kv_free(skc, sks, skc->skc_slab_size);
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list_add(&sks->sks_list, sks_list);
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EXIT;
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}
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static int
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__spl_slab_reclaim(spl_kmem_cache_t *skc)
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/*
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* Traverses all the partial slabs attached to a cache and free those
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* which which are currently empty, and have not been touched for
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* skc_delay seconds. This is to avoid thrashing.
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*/
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static void
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spl_slab_reclaim(spl_kmem_cache_t *skc, int flag)
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{
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spl_kmem_slab_t *sks, *m;
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int rc = 0;
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spl_kmem_obj_t *sko, *n;
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LIST_HEAD(sks_list);
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LIST_HEAD(sko_list);
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int size;
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ENTRY;
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ASSERT(spin_is_locked(&skc->skc_lock));
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/*
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* Free empty slabs which have not been touched in skc_delay
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* seconds. This delay time is important to avoid thrashing.
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* Empty slabs will be at the end of the skc_partial_list.
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* Move empty slabs and objects which have not been touched in
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* skc_delay seconds on to private lists to be freed outside
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* the spin lock. This delay time is important to avoid
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* thrashing however when flag is set the delay will not be
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* used. Empty slabs will be at the end of the skc_partial_list.
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*/
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spin_lock(&skc->skc_lock);
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list_for_each_entry_safe_reverse(sks, m, &skc->skc_partial_list,
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sks_list) {
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if (sks->sks_ref > 0)
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break;
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if (time_after(jiffies, sks->sks_age + skc->skc_delay * HZ)) {
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spl_slab_free(sks);
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rc++;
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if (flag || time_after(jiffies,sks->sks_age+skc->skc_delay*HZ))
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spl_slab_free(sks, &sks_list, &sko_list);
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}
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}
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/* Returns number of slabs reclaimed */
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RETURN(rc);
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}
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static int
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spl_slab_reclaim(spl_kmem_cache_t *skc)
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{
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int rc;
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ENTRY;
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spin_lock(&skc->skc_lock);
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rc = __spl_slab_reclaim(skc);
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spin_unlock(&skc->skc_lock);
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RETURN(rc);
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/*
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* We only have list of spl_kmem_obj_t's if they are located off
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* the slab, otherwise they get feed with the spl_kmem_slab_t.
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*/
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if (!list_empty(&sko_list)) {
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ASSERT(skc->skc_flags & KMC_OFFSLAB);
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size = P2ROUNDUP(skc->skc_obj_size, skc->skc_obj_align) +
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P2ROUNDUP(sizeof(spl_kmem_obj_t), skc->skc_obj_align);
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list_for_each_entry_safe(sko, n, &sko_list, sko_list)
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kv_free(skc, sko->sko_addr, size);
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}
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/* Size slabs properly to ensure they are not too large */
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list_for_each_entry_safe(sks, m, &sks_list, sks_list)
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kv_free(skc, sks, skc->skc_slab_size);
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EXIT;
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}
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/*
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* Called regularly on all caches to age objects out of the magazines
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* which have not been access in skc->skc_delay seconds. This prevents
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* idle magazines from holding memory which might be better used by
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* other caches or parts of the system. The delay is present to
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* prevent thrashing the magazine.
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*/
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static void
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spl_magazine_age(void *data)
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{
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spl_kmem_cache_t *skc = data;
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spl_kmem_magazine_t *skm = skc->skc_mag[smp_processor_id()];
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if (skm->skm_avail > 0 &&
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time_after(jiffies, skm->skm_age + skc->skc_delay * HZ))
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(void)spl_cache_flush(skc, skm, skm->skm_refill);
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}
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/*
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* Called regularly to keep a downward pressure on the size of idle
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* magazines and to release free slabs from the cache. This function
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* never calls the registered reclaim function, that only occures
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* under memory pressure or with a direct call to spl_kmem_reap().
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*/
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static void
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spl_cache_age(void *data)
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{
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spl_kmem_cache_t *skc =
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spl_get_work_data(data, spl_kmem_cache_t, skc_work.work);
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ASSERT(skc->skc_magic == SKC_MAGIC);
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on_each_cpu(spl_magazine_age, skc, 0, 1);
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spl_slab_reclaim(skc, 0);
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if (!test_bit(KMC_BIT_DESTROY, &skc->skc_flags))
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schedule_delayed_work(&skc->skc_work, 2 * skc->skc_delay * HZ);
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}
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/*
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* Size a slab based on the size of each aliged object plus spl_kmem_obj_t.
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* When on-slab we want to target SPL_KMEM_CACHE_OBJ_PER_SLAB. However,
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* for very small objects we may end up with more than this so as not
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* to waste space in the minimal allocation of a single page. Also for
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* very large objects we may use as few as SPL_KMEM_CACHE_OBJ_PER_SLAB_MIN,
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* lower than this and we will fail.
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*/
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static int
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spl_slab_size(spl_kmem_cache_t *skc, uint32_t *objs, uint32_t *size)
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{
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int max = ((uint64_t)1 << (MAX_ORDER - 1)) * PAGE_SIZE;
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int align = skc->skc_obj_align;
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*objs = SPL_KMEM_CACHE_OBJ_PER_SLAB;
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int sks_size, obj_size, max_size, align;
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if (skc->skc_flags & KMC_OFFSLAB) {
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*objs = SPL_KMEM_CACHE_OBJ_PER_SLAB;
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*size = sizeof(spl_kmem_slab_t);
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} else {
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resize:
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*size = P2ROUNDUP(sizeof(spl_kmem_slab_t), align) +
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*objs * (P2ROUNDUP(skc->skc_obj_size, align) +
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P2ROUNDUP(sizeof(spl_kmem_obj_t), align));
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align = skc->skc_obj_align;
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sks_size = P2ROUNDUP(sizeof(spl_kmem_slab_t), align);
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obj_size = P2ROUNDUP(skc->skc_obj_size, align) +
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P2ROUNDUP(sizeof(spl_kmem_obj_t), align);
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if (*size > max)
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GOTO(resize, *objs = *objs - 1);
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if (skc->skc_flags & KMC_KMEM)
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max_size = ((uint64_t)1 << (MAX_ORDER-1)) * PAGE_SIZE;
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else
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max_size = (32 * 1024 * 1024);
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ASSERT(*objs > 0);
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}
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ASSERTF(*size <= max, "%d < %d\n", *size, max);
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for (*size = PAGE_SIZE; *size <= max_size; *size += PAGE_SIZE) {
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*objs = (*size - sks_size) / obj_size;
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if (*objs >= SPL_KMEM_CACHE_OBJ_PER_SLAB)
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RETURN(0);
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}
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/*
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* Unable to satisfy target objets per slab, fallback to
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* allocating a maximally sized slab and assuming it can
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* contain the minimum objects count use it. If not fail.
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*/
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*size = max_size;
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*objs = (*size - sks_size) / obj_size;
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if (*objs >= SPL_KMEM_CACHE_OBJ_PER_SLAB_MIN)
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RETURN(0);
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}
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RETURN(-ENOSPC);
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}
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/*
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* Make a guess at reasonable per-cpu magazine size based on the size of
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* each object and the cost of caching N of them in each magazine. Long
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* term this should really adapt based on an observed usage heuristic.
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*/
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static int
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spl_magazine_size(spl_kmem_cache_t *skc)
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{
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int size, align = skc->skc_obj_align;
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ENTRY;
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/* Guesses for reasonable magazine sizes, they
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* should really adapt based on observed usage. */
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/* Per-magazine sizes below assume a 4Kib page size */
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if (P2ROUNDUP(skc->skc_obj_size, align) > (PAGE_SIZE * 256))
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size = 4;
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size = 4; /* Minimum 4Mib per-magazine */
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else if (P2ROUNDUP(skc->skc_obj_size, align) > (PAGE_SIZE * 32))
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size = 16;
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size = 16; /* Minimum 2Mib per-magazine */
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else if (P2ROUNDUP(skc->skc_obj_size, align) > (PAGE_SIZE))
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size = 64;
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size = 64; /* Minimum 256Kib per-magazine */
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else if (P2ROUNDUP(skc->skc_obj_size, align) > (PAGE_SIZE / 4))
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size = 128;
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size = 128; /* Minimum 128Kib per-magazine */
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else
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size = 512;
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size = 256;
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RETURN(size);
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}
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/*
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* Allocate a per-cpu magazine to assoicate with a specific core.
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*/
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static spl_kmem_magazine_t *
|
||||
spl_magazine_alloc(spl_kmem_cache_t *skc, int node)
|
||||
{
|
||||
@ -798,19 +874,21 @@ spl_magazine_alloc(spl_kmem_cache_t *skc, int node)
|
||||
sizeof(void *) * skc->skc_mag_size;
|
||||
ENTRY;
|
||||
|
||||
skm = kmem_alloc_node(size, GFP_KERNEL, node);
|
||||
skm = kmem_alloc_node(size, GFP_KERNEL | __GFP_NOFAIL, node);
|
||||
if (skm) {
|
||||
skm->skm_magic = SKM_MAGIC;
|
||||
skm->skm_avail = 0;
|
||||
skm->skm_size = skc->skc_mag_size;
|
||||
skm->skm_refill = skc->skc_mag_refill;
|
||||
if (!(skc->skc_flags & KMC_NOTOUCH))
|
||||
skm->skm_age = jiffies;
|
||||
}
|
||||
|
||||
RETURN(skm);
|
||||
}
|
||||
|
||||
/*
|
||||
* Free a per-cpu magazine assoicated with a specific core.
|
||||
*/
|
||||
static void
|
||||
spl_magazine_free(spl_kmem_magazine_t *skm)
|
||||
{
|
||||
@ -825,44 +903,72 @@ spl_magazine_free(spl_kmem_magazine_t *skm)
|
||||
EXIT;
|
||||
}
|
||||
|
||||
static void
|
||||
__spl_magazine_create(void *data)
|
||||
{
|
||||
spl_kmem_cache_t *skc = data;
|
||||
int id = smp_processor_id();
|
||||
|
||||
skc->skc_mag[id] = spl_magazine_alloc(skc, cpu_to_node(id));
|
||||
ASSERT(skc->skc_mag[id]);
|
||||
}
|
||||
|
||||
/*
|
||||
* Create all pre-cpu magazines of reasonable sizes.
|
||||
*/
|
||||
static int
|
||||
spl_magazine_create(spl_kmem_cache_t *skc)
|
||||
{
|
||||
int i;
|
||||
ENTRY;
|
||||
|
||||
skc->skc_mag_size = spl_magazine_size(skc);
|
||||
skc->skc_mag_refill = (skc->skc_mag_size + 1) / 2;
|
||||
|
||||
for_each_online_cpu(i) {
|
||||
skc->skc_mag[i] = spl_magazine_alloc(skc, cpu_to_node(i));
|
||||
if (!skc->skc_mag[i]) {
|
||||
for (i--; i >= 0; i--)
|
||||
spl_magazine_free(skc->skc_mag[i]);
|
||||
|
||||
RETURN(-ENOMEM);
|
||||
}
|
||||
}
|
||||
on_each_cpu(__spl_magazine_create, skc, 0, 1);
|
||||
|
||||
RETURN(0);
|
||||
}
|
||||
|
||||
static void
|
||||
spl_magazine_destroy(spl_kmem_cache_t *skc)
|
||||
__spl_magazine_destroy(void *data)
|
||||
{
|
||||
spl_kmem_magazine_t *skm;
|
||||
int i;
|
||||
ENTRY;
|
||||
spl_kmem_cache_t *skc = data;
|
||||
spl_kmem_magazine_t *skm = skc->skc_mag[smp_processor_id()];
|
||||
|
||||
for_each_online_cpu(i) {
|
||||
skm = skc->skc_mag[i];
|
||||
(void)spl_cache_flush(skc, skm, skm->skm_avail);
|
||||
spl_magazine_free(skm);
|
||||
}
|
||||
|
||||
/*
|
||||
* Destroy all pre-cpu magazines.
|
||||
*/
|
||||
static void
|
||||
spl_magazine_destroy(spl_kmem_cache_t *skc)
|
||||
{
|
||||
ENTRY;
|
||||
on_each_cpu(__spl_magazine_destroy, skc, 0, 1);
|
||||
EXIT;
|
||||
}
|
||||
|
||||
/*
|
||||
* Create a object cache based on the following arguments:
|
||||
* name cache name
|
||||
* size cache object size
|
||||
* align cache object alignment
|
||||
* ctor cache object constructor
|
||||
* dtor cache object destructor
|
||||
* reclaim cache object reclaim
|
||||
* priv cache private data for ctor/dtor/reclaim
|
||||
* vmp unused must be NULL
|
||||
* flags
|
||||
* KMC_NOTOUCH Disable cache object aging (unsupported)
|
||||
* KMC_NODEBUG Disable debugging (unsupported)
|
||||
* KMC_NOMAGAZINE Disable magazine (unsupported)
|
||||
* KMC_NOHASH Disable hashing (unsupported)
|
||||
* KMC_QCACHE Disable qcache (unsupported)
|
||||
* KMC_KMEM Force kmem backed cache
|
||||
* KMC_VMEM Force vmem backed cache
|
||||
* KMC_OFFSLAB Locate objects off the slab
|
||||
*/
|
||||
spl_kmem_cache_t *
|
||||
spl_kmem_cache_create(char *name, size_t size, size_t align,
|
||||
spl_kmem_ctor_t ctor,
|
||||
@ -908,6 +1014,7 @@ spl_kmem_cache_create(char *name, size_t size, size_t align,
|
||||
skc->skc_obj_size = size;
|
||||
skc->skc_obj_align = SPL_KMEM_CACHE_ALIGN;
|
||||
skc->skc_delay = SPL_KMEM_CACHE_DELAY;
|
||||
atomic_set(&skc->skc_ref, 0);
|
||||
|
||||
INIT_LIST_HEAD(&skc->skc_list);
|
||||
INIT_LIST_HEAD(&skc->skc_complete_list);
|
||||
@ -947,6 +1054,9 @@ spl_kmem_cache_create(char *name, size_t size, size_t align,
|
||||
if (rc)
|
||||
GOTO(out, rc);
|
||||
|
||||
spl_init_delayed_work(&skc->skc_work, spl_cache_age, skc);
|
||||
schedule_delayed_work(&skc->skc_work, 2 * skc->skc_delay * HZ);
|
||||
|
||||
down_write(&spl_kmem_cache_sem);
|
||||
list_add_tail(&skc->skc_list, &spl_kmem_cache_list);
|
||||
up_write(&spl_kmem_cache_sem);
|
||||
@ -959,10 +1069,13 @@ out:
|
||||
}
|
||||
EXPORT_SYMBOL(spl_kmem_cache_create);
|
||||
|
||||
/*
|
||||
* Destroy a cache and all objects assoicated with the cache.
|
||||
*/
|
||||
void
|
||||
spl_kmem_cache_destroy(spl_kmem_cache_t *skc)
|
||||
{
|
||||
spl_kmem_slab_t *sks, *m;
|
||||
DECLARE_WAIT_QUEUE_HEAD(wq);
|
||||
ENTRY;
|
||||
|
||||
ASSERT(skc->skc_magic == SKC_MAGIC);
|
||||
@ -971,20 +1084,27 @@ spl_kmem_cache_destroy(spl_kmem_cache_t *skc)
|
||||
list_del_init(&skc->skc_list);
|
||||
up_write(&spl_kmem_cache_sem);
|
||||
|
||||
/* Cancel any and wait for any pending delayed work */
|
||||
ASSERT(!test_and_set_bit(KMC_BIT_DESTROY, &skc->skc_flags));
|
||||
cancel_delayed_work(&skc->skc_work);
|
||||
flush_scheduled_work();
|
||||
|
||||
/* Wait until all current callers complete, this is mainly
|
||||
* to catch the case where a low memory situation triggers a
|
||||
* cache reaping action which races with this destroy. */
|
||||
wait_event(wq, atomic_read(&skc->skc_ref) == 0);
|
||||
|
||||
spl_magazine_destroy(skc);
|
||||
spl_slab_reclaim(skc, 1);
|
||||
spin_lock(&skc->skc_lock);
|
||||
|
||||
/* Validate there are no objects in use and free all the
|
||||
* spl_kmem_slab_t, spl_kmem_obj_t, and object buffers. */
|
||||
ASSERT3U(skc->skc_slab_alloc, ==, 0);
|
||||
ASSERT3U(skc->skc_obj_alloc, ==, 0);
|
||||
ASSERT3U(skc->skc_slab_total, ==, 0);
|
||||
ASSERT3U(skc->skc_obj_total, ==, 0);
|
||||
ASSERT(list_empty(&skc->skc_complete_list));
|
||||
ASSERT(skc->skc_slab_alloc == 0);
|
||||
ASSERT(skc->skc_obj_alloc == 0);
|
||||
|
||||
list_for_each_entry_safe(sks, m, &skc->skc_partial_list, sks_list)
|
||||
spl_slab_free(sks);
|
||||
|
||||
ASSERT(skc->skc_slab_total == 0);
|
||||
ASSERT(skc->skc_obj_total == 0);
|
||||
|
||||
kmem_free(skc->skc_name, skc->skc_name_size);
|
||||
spin_unlock(&skc->skc_lock);
|
||||
@ -995,6 +1115,10 @@ spl_kmem_cache_destroy(spl_kmem_cache_t *skc)
|
||||
}
|
||||
EXPORT_SYMBOL(spl_kmem_cache_destroy);
|
||||
|
||||
/*
|
||||
* Allocate an object from a slab attached to the cache. This is used to
|
||||
* repopulate the per-cpu magazine caches in batches when they run low.
|
||||
*/
|
||||
static void *
|
||||
spl_cache_obj(spl_kmem_cache_t *skc, spl_kmem_slab_t *sks)
|
||||
{
|
||||
@ -1030,10 +1154,11 @@ spl_cache_obj(spl_kmem_cache_t *skc, spl_kmem_slab_t *sks)
|
||||
return sko->sko_addr;
|
||||
}
|
||||
|
||||
/* No available objects create a new slab. Since this is an
|
||||
* expensive operation we do it without holding the spinlock
|
||||
* and only briefly aquire it when we link in the fully
|
||||
* allocated and constructed slab.
|
||||
/*
|
||||
* No available objects on any slabsi, create a new slab. Since this
|
||||
* is an expensive operation we do it without holding the spinlock and
|
||||
* only briefly aquire it when we link in the fully allocated and
|
||||
* constructed slab.
|
||||
*/
|
||||
static spl_kmem_slab_t *
|
||||
spl_cache_grow(spl_kmem_cache_t *skc, int flags)
|
||||
@ -1042,34 +1167,42 @@ spl_cache_grow(spl_kmem_cache_t *skc, int flags)
|
||||
ENTRY;
|
||||
|
||||
ASSERT(skc->skc_magic == SKC_MAGIC);
|
||||
|
||||
if (flags & __GFP_WAIT) {
|
||||
flags |= __GFP_NOFAIL;
|
||||
local_irq_enable();
|
||||
might_sleep();
|
||||
|
||||
/*
|
||||
* Before allocating a new slab check if the slab is being reaped.
|
||||
* If it is there is a good chance we can wait until it finishes
|
||||
* and then use one of the newly freed but not aged-out slabs.
|
||||
*/
|
||||
if (test_bit(KMC_BIT_REAPING, &skc->skc_flags)) {
|
||||
schedule();
|
||||
GOTO(out, sks= NULL);
|
||||
}
|
||||
|
||||
sks = spl_slab_alloc(skc, flags);
|
||||
if (sks == NULL) {
|
||||
if (flags & __GFP_WAIT)
|
||||
local_irq_disable();
|
||||
/* Allocate a new slab for the cache */
|
||||
sks = spl_slab_alloc(skc, flags | __GFP_NORETRY | __GFP_NOWARN);
|
||||
if (sks == NULL)
|
||||
GOTO(out, sks = NULL);
|
||||
|
||||
RETURN(NULL);
|
||||
}
|
||||
|
||||
if (flags & __GFP_WAIT)
|
||||
local_irq_disable();
|
||||
|
||||
/* Link the new empty slab in to the end of skc_partial_list */
|
||||
/* Link the new empty slab in to the end of skc_partial_list. */
|
||||
spin_lock(&skc->skc_lock);
|
||||
skc->skc_slab_total++;
|
||||
skc->skc_obj_total += sks->sks_objs;
|
||||
list_add_tail(&sks->sks_list, &skc->skc_partial_list);
|
||||
spin_unlock(&skc->skc_lock);
|
||||
out:
|
||||
local_irq_disable();
|
||||
|
||||
RETURN(sks);
|
||||
}
|
||||
|
||||
/*
|
||||
* Refill a per-cpu magazine with objects from the slabs for this
|
||||
* cache. Ideally the magazine can be repopulated using existing
|
||||
* objects which have been released, however if we are unable to
|
||||
* locate enough free objects new slabs of objects will be created.
|
||||
*/
|
||||
static int
|
||||
spl_cache_refill(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flags)
|
||||
{
|
||||
@ -1080,13 +1213,11 @@ spl_cache_refill(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flags)
|
||||
ASSERT(skc->skc_magic == SKC_MAGIC);
|
||||
ASSERT(skm->skm_magic == SKM_MAGIC);
|
||||
|
||||
/* XXX: Check for refill bouncing by age perhaps */
|
||||
refill = MIN(skm->skm_refill, skm->skm_size - skm->skm_avail);
|
||||
|
||||
spin_lock(&skc->skc_lock);
|
||||
|
||||
while (refill > 0) {
|
||||
/* No slabs available we must grow the cache */
|
||||
/* No slabs available we may need to grow the cache */
|
||||
if (list_empty(&skc->skc_partial_list)) {
|
||||
spin_unlock(&skc->skc_lock);
|
||||
|
||||
@ -1135,6 +1266,9 @@ out:
|
||||
RETURN(rc);
|
||||
}
|
||||
|
||||
/*
|
||||
* Release an object back to the slab from which it came.
|
||||
*/
|
||||
static void
|
||||
spl_cache_shrink(spl_kmem_cache_t *skc, void *obj)
|
||||
{
|
||||
@ -1176,6 +1310,13 @@ spl_cache_shrink(spl_kmem_cache_t *skc, void *obj)
|
||||
EXIT;
|
||||
}
|
||||
|
||||
/*
|
||||
* Release a batch of objects from a per-cpu magazine back to their
|
||||
* respective slabs. This occurs when we exceed the magazine size,
|
||||
* are under memory pressure, when the cache is idle, or during
|
||||
* cache cleanup. The flush argument contains the number of entries
|
||||
* to remove from the magazine.
|
||||
*/
|
||||
static int
|
||||
spl_cache_flush(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flush)
|
||||
{
|
||||
@ -1185,12 +1326,17 @@ spl_cache_flush(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flush)
|
||||
ASSERT(skc->skc_magic == SKC_MAGIC);
|
||||
ASSERT(skm->skm_magic == SKM_MAGIC);
|
||||
|
||||
/*
|
||||
* XXX: Currently we simply return objects from the magazine to
|
||||
* the slabs in fifo order. The ideal thing to do from a memory
|
||||
* fragmentation standpoint is to cheaply determine the set of
|
||||
* objects in the magazine which will result in the largest
|
||||
* number of free slabs if released from the magazine.
|
||||
*/
|
||||
spin_lock(&skc->skc_lock);
|
||||
|
||||
for (i = 0; i < count; i++)
|
||||
spl_cache_shrink(skc, skm->skm_objs[i]);
|
||||
|
||||
// __spl_slab_reclaim(skc);
|
||||
skm->skm_avail -= count;
|
||||
memmove(skm->skm_objs, &(skm->skm_objs[count]),
|
||||
sizeof(void *) * skm->skm_avail);
|
||||
@ -1200,6 +1346,10 @@ spl_cache_flush(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flush)
|
||||
RETURN(count);
|
||||
}
|
||||
|
||||
/*
|
||||
* Allocate an object from the per-cpu magazine, or if the magazine
|
||||
* is empty directly allocate from a slab and repopulate the magazine.
|
||||
*/
|
||||
void *
|
||||
spl_kmem_cache_alloc(spl_kmem_cache_t *skc, int flags)
|
||||
{
|
||||
@ -1209,7 +1359,9 @@ spl_kmem_cache_alloc(spl_kmem_cache_t *skc, int flags)
|
||||
ENTRY;
|
||||
|
||||
ASSERT(skc->skc_magic == SKC_MAGIC);
|
||||
ASSERT(flags & KM_SLEEP); /* XXX: KM_NOSLEEP not yet supported */
|
||||
ASSERT(!test_bit(KMC_BIT_DESTROY, &skc->skc_flags));
|
||||
ASSERT(flags & KM_SLEEP);
|
||||
atomic_inc(&skc->skc_ref);
|
||||
local_irq_save(irq_flags);
|
||||
|
||||
restart:
|
||||
@ -1225,7 +1377,6 @@ restart:
|
||||
if (likely(skm->skm_avail)) {
|
||||
/* Object available in CPU cache, use it */
|
||||
obj = skm->skm_objs[--skm->skm_avail];
|
||||
if (!(skc->skc_flags & KMC_NOTOUCH))
|
||||
skm->skm_age = jiffies;
|
||||
} else {
|
||||
/* Per-CPU cache empty, directly allocate from
|
||||
@ -1240,11 +1391,18 @@ restart:
|
||||
|
||||
/* Pre-emptively migrate object to CPU L1 cache */
|
||||
prefetchw(obj);
|
||||
atomic_dec(&skc->skc_ref);
|
||||
|
||||
RETURN(obj);
|
||||
}
|
||||
EXPORT_SYMBOL(spl_kmem_cache_alloc);
|
||||
|
||||
/*
|
||||
* Free an object back to the local per-cpu magazine, there is no
|
||||
* guarantee that this is the same magazine the object was originally
|
||||
* allocated from. We may need to flush entire from the magazine
|
||||
* back to the slabs to make space.
|
||||
*/
|
||||
void
|
||||
spl_kmem_cache_free(spl_kmem_cache_t *skc, void *obj)
|
||||
{
|
||||
@ -1253,6 +1411,8 @@ spl_kmem_cache_free(spl_kmem_cache_t *skc, void *obj)
|
||||
ENTRY;
|
||||
|
||||
ASSERT(skc->skc_magic == SKC_MAGIC);
|
||||
ASSERT(!test_bit(KMC_BIT_DESTROY, &skc->skc_flags));
|
||||
atomic_inc(&skc->skc_ref);
|
||||
local_irq_save(flags);
|
||||
|
||||
/* Safe to update per-cpu structure without lock, but
|
||||
@ -1270,62 +1430,87 @@ spl_kmem_cache_free(spl_kmem_cache_t *skc, void *obj)
|
||||
skm->skm_objs[skm->skm_avail++] = obj;
|
||||
|
||||
local_irq_restore(flags);
|
||||
atomic_dec(&skc->skc_ref);
|
||||
|
||||
EXIT;
|
||||
}
|
||||
EXPORT_SYMBOL(spl_kmem_cache_free);
|
||||
|
||||
/*
|
||||
* The generic shrinker function for all caches. Under linux a shrinker
|
||||
* may not be tightly coupled with a slab cache. In fact linux always
|
||||
* systematically trys calling all registered shrinker callbacks which
|
||||
* report that they contain unused objects. Because of this we only
|
||||
* register one shrinker function in the shim layer for all slab caches.
|
||||
* We always attempt to shrink all caches when this generic shrinker
|
||||
* is called. The shrinker should return the number of free objects
|
||||
* in the cache when called with nr_to_scan == 0 but not attempt to
|
||||
* free any objects. When nr_to_scan > 0 it is a request that nr_to_scan
|
||||
* objects should be freed, because Solaris semantics are to free
|
||||
* all available objects we may free more objects than requested.
|
||||
*/
|
||||
static int
|
||||
spl_kmem_cache_generic_shrinker(int nr_to_scan, unsigned int gfp_mask)
|
||||
{
|
||||
spl_kmem_cache_t *skc;
|
||||
int unused = 0;
|
||||
|
||||
/* Under linux a shrinker is not tightly coupled with a slab
|
||||
* cache. In fact linux always systematically trys calling all
|
||||
* registered shrinker callbacks until its target reclamation level
|
||||
* is reached. Because of this we only register one shrinker
|
||||
* function in the shim layer for all slab caches. And we always
|
||||
* attempt to shrink all caches when this generic shrinker is called.
|
||||
*/
|
||||
down_read(&spl_kmem_cache_sem);
|
||||
|
||||
list_for_each_entry(skc, &spl_kmem_cache_list, skc_list)
|
||||
list_for_each_entry(skc, &spl_kmem_cache_list, skc_list) {
|
||||
if (nr_to_scan)
|
||||
spl_kmem_cache_reap_now(skc);
|
||||
|
||||
/*
|
||||
* Presume everything alloc'ed in reclaimable, this ensures
|
||||
* we are called again with nr_to_scan > 0 so can try and
|
||||
* reclaim. The exact number is not important either so
|
||||
* we forgo taking this already highly contented lock.
|
||||
*/
|
||||
unused += skc->skc_obj_alloc;
|
||||
}
|
||||
up_read(&spl_kmem_cache_sem);
|
||||
|
||||
/* XXX: Under linux we should return the remaining number of
|
||||
* entries in the cache. We should do this as well.
|
||||
*/
|
||||
return 1;
|
||||
return (unused * sysctl_vfs_cache_pressure) / 100;
|
||||
}
|
||||
|
||||
/*
|
||||
* Call the registered reclaim function for a cache. Depending on how
|
||||
* many and which objects are released it may simply repopulate the
|
||||
* local magazine which will then need to age-out. Objects which cannot
|
||||
* fit in the magazine we will be released back to their slabs which will
|
||||
* also need to age out before being release. This is all just best
|
||||
* effort and we do not want to thrash creating and destroying slabs.
|
||||
*/
|
||||
void
|
||||
spl_kmem_cache_reap_now(spl_kmem_cache_t *skc)
|
||||
{
|
||||
spl_kmem_magazine_t *skm;
|
||||
int i;
|
||||
ENTRY;
|
||||
|
||||
ASSERT(skc->skc_magic == SKC_MAGIC);
|
||||
ASSERT(!test_bit(KMC_BIT_DESTROY, &skc->skc_flags));
|
||||
|
||||
/* Prevent concurrent cache reaping when contended */
|
||||
if (test_and_set_bit(KMC_BIT_REAPING, &skc->skc_flags)) {
|
||||
EXIT;
|
||||
return;
|
||||
}
|
||||
|
||||
atomic_inc(&skc->skc_ref);
|
||||
|
||||
if (skc->skc_reclaim)
|
||||
skc->skc_reclaim(skc->skc_private);
|
||||
|
||||
/* Ensure per-CPU caches which are idle gradually flush */
|
||||
for_each_online_cpu(i) {
|
||||
skm = skc->skc_mag[i];
|
||||
|
||||
if (time_after(jiffies, skm->skm_age + skc->skc_delay * HZ))
|
||||
(void)spl_cache_flush(skc, skm, skm->skm_refill);
|
||||
}
|
||||
|
||||
spl_slab_reclaim(skc);
|
||||
spl_slab_reclaim(skc, 0);
|
||||
clear_bit(KMC_BIT_REAPING, &skc->skc_flags);
|
||||
atomic_dec(&skc->skc_ref);
|
||||
|
||||
EXIT;
|
||||
}
|
||||
EXPORT_SYMBOL(spl_kmem_cache_reap_now);
|
||||
|
||||
/*
|
||||
* Reap all free slabs from all registered caches.
|
||||
*/
|
||||
void
|
||||
spl_kmem_reap(void)
|
||||
{
|
||||
|
||||
@ -40,6 +40,7 @@
|
||||
#include <linux/module.h>
|
||||
#include <linux/device.h>
|
||||
#include <linux/list.h>
|
||||
#include <linux/swap.h>
|
||||
|
||||
#include <asm/ioctls.h>
|
||||
#include <asm/uaccess.h>
|
||||
|
||||
File diff suppressed because it is too large
Load Diff
Loading…
Reference in New Issue
Block a user