1What: /sys/kernel/slab 2Date: May 2007 3KernelVersion: 2.6.22 4Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 5 Christoph Lameter <cl@linux-foundation.org> 6Description: 7 The /sys/kernel/slab directory contains a snapshot of the 8 internal state of the SLUB allocator for each cache. Certain 9 files may be modified to change the behavior of the cache (and 10 any cache it aliases, if any). 11Users: kernel memory tuning tools 12 13What: /sys/kernel/slab/cache/aliases 14Date: May 2007 15KernelVersion: 2.6.22 16Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 17 Christoph Lameter <cl@linux-foundation.org> 18Description: 19 The aliases file is read-only and specifies how many caches 20 have merged into this cache. 21 22What: /sys/kernel/slab/cache/align 23Date: May 2007 24KernelVersion: 2.6.22 25Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 26 Christoph Lameter <cl@linux-foundation.org> 27Description: 28 The align file is read-only and specifies the cache's object 29 alignment in bytes. 30 31What: /sys/kernel/slab/cache/alloc_calls 32Date: May 2007 33KernelVersion: 2.6.22 34Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 35 Christoph Lameter <cl@linux-foundation.org> 36Description: 37 The alloc_calls file is read-only and lists the kernel code 38 locations from which allocations for this cache were performed. 39 The alloc_calls file only contains information if debugging is 40 enabled for that cache (see Documentation/vm/slub.txt). 41 42What: /sys/kernel/slab/cache/alloc_fastpath 43Date: February 2008 44KernelVersion: 2.6.25 45Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 46 Christoph Lameter <cl@linux-foundation.org> 47Description: 48 The alloc_fastpath file shows how many objects have been 49 allocated using the fast path. It can be written to clear the 50 current count. 51 Available when CONFIG_SLUB_STATS is enabled. 52 53What: /sys/kernel/slab/cache/alloc_from_partial 54Date: February 2008 55KernelVersion: 2.6.25 56Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 57 Christoph Lameter <cl@linux-foundation.org> 58Description: 59 The alloc_from_partial file shows how many times a cpu slab has 60 been full and it has been refilled by using a slab from the list 61 of partially used slabs. It can be written to clear the current 62 count. 63 Available when CONFIG_SLUB_STATS is enabled. 64 65What: /sys/kernel/slab/cache/alloc_refill 66Date: February 2008 67KernelVersion: 2.6.25 68Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 69 Christoph Lameter <cl@linux-foundation.org> 70Description: 71 The alloc_refill file shows how many times the per-cpu freelist 72 was empty but there were objects available as the result of 73 remote cpu frees. It can be written to clear the current count. 74 Available when CONFIG_SLUB_STATS is enabled. 75 76What: /sys/kernel/slab/cache/alloc_slab 77Date: February 2008 78KernelVersion: 2.6.25 79Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 80 Christoph Lameter <cl@linux-foundation.org> 81Description: 82 The alloc_slab file is shows how many times a new slab had to 83 be allocated from the page allocator. It can be written to 84 clear the current count. 85 Available when CONFIG_SLUB_STATS is enabled. 86 87What: /sys/kernel/slab/cache/alloc_slowpath 88Date: February 2008 89KernelVersion: 2.6.25 90Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 91 Christoph Lameter <cl@linux-foundation.org> 92Description: 93 The alloc_slowpath file shows how many objects have been 94 allocated using the slow path because of a refill or 95 allocation from a partial or new slab. It can be written to 96 clear the current count. 97 Available when CONFIG_SLUB_STATS is enabled. 98 99What: /sys/kernel/slab/cache/cache_dma 100Date: May 2007 101KernelVersion: 2.6.22 102Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 103 Christoph Lameter <cl@linux-foundation.org> 104Description: 105 The cache_dma file is read-only and specifies whether objects 106 are from ZONE_DMA. 107 Available when CONFIG_ZONE_DMA is enabled. 108 109What: /sys/kernel/slab/cache/cpu_slabs 110Date: May 2007 111KernelVersion: 2.6.22 112Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 113 Christoph Lameter <cl@linux-foundation.org> 114Description: 115 The cpu_slabs file is read-only and displays how many cpu slabs 116 are active and their NUMA locality. 117 118What: /sys/kernel/slab/cache/cpuslab_flush 119Date: April 2009 120KernelVersion: 2.6.31 121Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 122 Christoph Lameter <cl@linux-foundation.org> 123Description: 124 The file cpuslab_flush shows how many times a cache's cpu slabs 125 have been flushed as the result of destroying or shrinking a 126 cache, a cpu going offline, or as the result of forcing an 127 allocation from a certain node. It can be written to clear the 128 current count. 129 Available when CONFIG_SLUB_STATS is enabled. 130 131What: /sys/kernel/slab/cache/ctor 132Date: May 2007 133KernelVersion: 2.6.22 134Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 135 Christoph Lameter <cl@linux-foundation.org> 136Description: 137 The ctor file is read-only and specifies the cache's object 138 constructor function, which is invoked for each object when a 139 new slab is allocated. 140 141What: /sys/kernel/slab/cache/deactivate_empty 142Date: February 2008 143KernelVersion: 2.6.25 144Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 145 Christoph Lameter <cl@linux-foundation.org> 146Description: 147 The deactivate_empty file shows how many times an empty cpu slab 148 was deactivated. It can be written to clear the current count. 149 Available when CONFIG_SLUB_STATS is enabled. 150 151What: /sys/kernel/slab/cache/deactivate_full 152Date: February 2008 153KernelVersion: 2.6.25 154Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 155 Christoph Lameter <cl@linux-foundation.org> 156Description: 157 The deactivate_full file shows how many times a full cpu slab 158 was deactivated. It can be written to clear the current count. 159 Available when CONFIG_SLUB_STATS is enabled. 160 161What: /sys/kernel/slab/cache/deactivate_remote_frees 162Date: February 2008 163KernelVersion: 2.6.25 164Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 165 Christoph Lameter <cl@linux-foundation.org> 166Description: 167 The deactivate_remote_frees file shows how many times a cpu slab 168 has been deactivated and contained free objects that were freed 169 remotely. It can be written to clear the current count. 170 Available when CONFIG_SLUB_STATS is enabled. 171 172What: /sys/kernel/slab/cache/deactivate_to_head 173Date: February 2008 174KernelVersion: 2.6.25 175Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 176 Christoph Lameter <cl@linux-foundation.org> 177Description: 178 The deactivate_to_head file shows how many times a partial cpu 179 slab was deactivated and added to the head of its node's partial 180 list. It can be written to clear the current count. 181 Available when CONFIG_SLUB_STATS is enabled. 182 183What: /sys/kernel/slab/cache/deactivate_to_tail 184Date: February 2008 185KernelVersion: 2.6.25 186Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 187 Christoph Lameter <cl@linux-foundation.org> 188Description: 189 The deactivate_to_tail file shows how many times a partial cpu 190 slab was deactivated and added to the tail of its node's partial 191 list. It can be written to clear the current count. 192 Available when CONFIG_SLUB_STATS is enabled. 193 194What: /sys/kernel/slab/cache/destroy_by_rcu 195Date: May 2007 196KernelVersion: 2.6.22 197Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 198 Christoph Lameter <cl@linux-foundation.org> 199Description: 200 The destroy_by_rcu file is read-only and specifies whether 201 slabs (not objects) are freed by rcu. 202 203What: /sys/kernel/slab/cache/free_add_partial 204Date: February 2008 205KernelVersion: 2.6.25 206Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 207 Christoph Lameter <cl@linux-foundation.org> 208Description: 209 The free_add_partial file shows how many times an object has 210 been freed in a full slab so that it had to added to its node's 211 partial list. It can be written to clear the current count. 212 Available when CONFIG_SLUB_STATS is enabled. 213 214What: /sys/kernel/slab/cache/free_calls 215Date: May 2007 216KernelVersion: 2.6.22 217Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 218 Christoph Lameter <cl@linux-foundation.org> 219Description: 220 The free_calls file is read-only and lists the locations of 221 object frees if slab debugging is enabled (see 222 Documentation/vm/slub.txt). 223 224What: /sys/kernel/slab/cache/free_fastpath 225Date: February 2008 226KernelVersion: 2.6.25 227Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 228 Christoph Lameter <cl@linux-foundation.org> 229Description: 230 The free_fastpath file shows how many objects have been freed 231 using the fast path because it was an object from the cpu slab. 232 It can be written to clear the current count. 233 Available when CONFIG_SLUB_STATS is enabled. 234 235What: /sys/kernel/slab/cache/free_frozen 236Date: February 2008 237KernelVersion: 2.6.25 238Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 239 Christoph Lameter <cl@linux-foundation.org> 240Description: 241 The free_frozen file shows how many objects have been freed to 242 a frozen slab (i.e. a remote cpu slab). It can be written to 243 clear the current count. 244 Available when CONFIG_SLUB_STATS is enabled. 245 246What: /sys/kernel/slab/cache/free_remove_partial 247Date: February 2008 248KernelVersion: 2.6.25 249Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 250 Christoph Lameter <cl@linux-foundation.org> 251Description: 252 The free_remove_partial file shows how many times an object has 253 been freed to a now-empty slab so that it had to be removed from 254 its node's partial list. It can be written to clear the current 255 count. 256 Available when CONFIG_SLUB_STATS is enabled. 257 258What: /sys/kernel/slab/cache/free_slab 259Date: February 2008 260KernelVersion: 2.6.25 261Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 262 Christoph Lameter <cl@linux-foundation.org> 263Description: 264 The free_slab file shows how many times an empty slab has been 265 freed back to the page allocator. It can be written to clear 266 the current count. 267 Available when CONFIG_SLUB_STATS is enabled. 268 269What: /sys/kernel/slab/cache/free_slowpath 270Date: February 2008 271KernelVersion: 2.6.25 272Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 273 Christoph Lameter <cl@linux-foundation.org> 274Description: 275 The free_slowpath file shows how many objects have been freed 276 using the slow path (i.e. to a full or partial slab). It can 277 be written to clear the current count. 278 Available when CONFIG_SLUB_STATS is enabled. 279 280What: /sys/kernel/slab/cache/hwcache_align 281Date: May 2007 282KernelVersion: 2.6.22 283Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 284 Christoph Lameter <cl@linux-foundation.org> 285Description: 286 The hwcache_align file is read-only and specifies whether 287 objects are aligned on cachelines. 288 289What: /sys/kernel/slab/cache/min_partial 290Date: February 2009 291KernelVersion: 2.6.30 292Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 293 David Rientjes <rientjes@google.com> 294Description: 295 The min_partial file specifies how many empty slabs shall 296 remain on a node's partial list to avoid the overhead of 297 allocating new slabs. Such slabs may be reclaimed by utilizing 298 the shrink file. 299 300What: /sys/kernel/slab/cache/object_size 301Date: May 2007 302KernelVersion: 2.6.22 303Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 304 Christoph Lameter <cl@linux-foundation.org> 305Description: 306 The object_size file is read-only and specifies the cache's 307 object size. 308 309What: /sys/kernel/slab/cache/objects 310Date: May 2007 311KernelVersion: 2.6.22 312Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 313 Christoph Lameter <cl@linux-foundation.org> 314Description: 315 The objects file is read-only and displays how many objects are 316 active and from which nodes they are from. 317 318What: /sys/kernel/slab/cache/objects_partial 319Date: April 2008 320KernelVersion: 2.6.26 321Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 322 Christoph Lameter <cl@linux-foundation.org> 323Description: 324 The objects_partial file is read-only and displays how many 325 objects are on partial slabs and from which nodes they are 326 from. 327 328What: /sys/kernel/slab/cache/objs_per_slab 329Date: May 2007 330KernelVersion: 2.6.22 331Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 332 Christoph Lameter <cl@linux-foundation.org> 333Description: 334 The file objs_per_slab is read-only and specifies how many 335 objects may be allocated from a single slab of the order 336 specified in /sys/kernel/slab/cache/order. 337 338What: /sys/kernel/slab/cache/order 339Date: May 2007 340KernelVersion: 2.6.22 341Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 342 Christoph Lameter <cl@linux-foundation.org> 343Description: 344 The order file specifies the page order at which new slabs are 345 allocated. It is writable and can be changed to increase the 346 number of objects per slab. If a slab cannot be allocated 347 because of fragmentation, SLUB will retry with the minimum order 348 possible depending on its characteristics. 349 350What: /sys/kernel/slab/cache/order_fallback 351Date: April 2008 352KernelVersion: 2.6.26 353Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 354 Christoph Lameter <cl@linux-foundation.org> 355Description: 356 The order_fallback file shows how many times an allocation of a 357 new slab has not been possible at the cache's order and instead 358 fallen back to its minimum possible order. It can be written to 359 clear the current count. 360 Available when CONFIG_SLUB_STATS is enabled. 361 362What: /sys/kernel/slab/cache/partial 363Date: May 2007 364KernelVersion: 2.6.22 365Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 366 Christoph Lameter <cl@linux-foundation.org> 367Description: 368 The partial file is read-only and displays how long many 369 partial slabs there are and how long each node's list is. 370 371What: /sys/kernel/slab/cache/poison 372Date: May 2007 373KernelVersion: 2.6.22 374Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 375 Christoph Lameter <cl@linux-foundation.org> 376Description: 377 The poison file specifies whether objects should be poisoned 378 when a new slab is allocated. 379 380What: /sys/kernel/slab/cache/reclaim_account 381Date: May 2007 382KernelVersion: 2.6.22 383Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 384 Christoph Lameter <cl@linux-foundation.org> 385Description: 386 The reclaim_account file specifies whether the cache's objects 387 are reclaimable (and grouped by their mobility). 388 389What: /sys/kernel/slab/cache/red_zone 390Date: May 2007 391KernelVersion: 2.6.22 392Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 393 Christoph Lameter <cl@linux-foundation.org> 394Description: 395 The red_zone file specifies whether the cache's objects are red 396 zoned. 397 398What: /sys/kernel/slab/cache/remote_node_defrag_ratio 399Date: January 2008 400KernelVersion: 2.6.25 401Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 402 Christoph Lameter <cl@linux-foundation.org> 403Description: 404 The file remote_node_defrag_ratio specifies the percentage of 405 times SLUB will attempt to refill the cpu slab with a partial 406 slab from a remote node as opposed to allocating a new slab on 407 the local node. This reduces the amount of wasted memory over 408 the entire system but can be expensive. 409 Available when CONFIG_NUMA is enabled. 410 411What: /sys/kernel/slab/cache/sanity_checks 412Date: May 2007 413KernelVersion: 2.6.22 414Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 415 Christoph Lameter <cl@linux-foundation.org> 416Description: 417 The sanity_checks file specifies whether expensive checks 418 should be performed on free and, at minimum, enables double free 419 checks. Caches that enable sanity_checks cannot be merged with 420 caches that do not. 421 422What: /sys/kernel/slab/cache/shrink 423Date: May 2007 424KernelVersion: 2.6.22 425Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 426 Christoph Lameter <cl@linux-foundation.org> 427Description: 428 The shrink file is written when memory should be reclaimed from 429 a cache. Empty partial slabs are freed and the partial list is 430 sorted so the slabs with the fewest available objects are used 431 first. 432 433What: /sys/kernel/slab/cache/slab_size 434Date: May 2007 435KernelVersion: 2.6.22 436Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 437 Christoph Lameter <cl@linux-foundation.org> 438Description: 439 The slab_size file is read-only and specifies the object size 440 with metadata (debugging information and alignment) in bytes. 441 442What: /sys/kernel/slab/cache/slabs 443Date: May 2007 444KernelVersion: 2.6.22 445Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 446 Christoph Lameter <cl@linux-foundation.org> 447Description: 448 The slabs file is read-only and displays how long many slabs 449 there are (both cpu and partial) and from which nodes they are 450 from. 451 452What: /sys/kernel/slab/cache/store_user 453Date: May 2007 454KernelVersion: 2.6.22 455Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 456 Christoph Lameter <cl@linux-foundation.org> 457Description: 458 The store_user file specifies whether the location of 459 allocation or free should be tracked for a cache. 460 461What: /sys/kernel/slab/cache/total_objects 462Date: April 2008 463KernelVersion: 2.6.26 464Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 465 Christoph Lameter <cl@linux-foundation.org> 466Description: 467 The total_objects file is read-only and displays how many total 468 objects a cache has and from which nodes they are from. 469 470What: /sys/kernel/slab/cache/trace 471Date: May 2007 472KernelVersion: 2.6.22 473Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 474 Christoph Lameter <cl@linux-foundation.org> 475Description: 476 The trace file specifies whether object allocations and frees 477 should be traced. 478 479What: /sys/kernel/slab/cache/validate 480Date: May 2007 481KernelVersion: 2.6.22 482Contact: Pekka Enberg <penberg@cs.helsinki.fi>, 483 Christoph Lameter <cl@linux-foundation.org> 484Description: 485 Writing to the validate file causes SLUB to traverse all of its 486 cache's objects and check the validity of metadata. 487