diff options
author | David Rientjes <rientjes@google.com> | 2009-09-21 20:04:31 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-22 10:17:47 -0400 |
commit | 4af5a2f770cc8575840ccb1514ec76ecb592985c (patch) | |
tree | 7af18234d7d171a946925e65e987fd51648be3aa | |
parent | 19da3dd157f8db6fe727ff268dab4791d55a6371 (diff) |
flex_array: add flex_array_shrink function
Add a new function to the flex_array API:
int flex_array_shrink(struct flex_array *fa)
This function will free all unused second-level pages. Since elements are
now poisoned if they are not allocated with __GFP_ZERO, it's possible to
identify parts that consist solely of unused elements.
flex_array_shrink() returns the number of pages freed.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | include/linux/flex_array.h | 1 | ||||
-rw-r--r-- | lib/flex_array.c | 40 |
2 files changed, 41 insertions, 0 deletions
diff --git a/include/linux/flex_array.h b/include/linux/flex_array.h index 3887b21f883f..f12401e485fe 100644 --- a/include/linux/flex_array.h +++ b/include/linux/flex_array.h | |||
@@ -46,5 +46,6 @@ int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src, | |||
46 | gfp_t flags); | 46 | gfp_t flags); |
47 | int flex_array_clear(struct flex_array *fa, unsigned int element_nr); | 47 | int flex_array_clear(struct flex_array *fa, unsigned int element_nr); |
48 | void *flex_array_get(struct flex_array *fa, unsigned int element_nr); | 48 | void *flex_array_get(struct flex_array *fa, unsigned int element_nr); |
49 | int flex_array_shrink(struct flex_array *fa); | ||
49 | 50 | ||
50 | #endif /* _FLEX_ARRAY_H */ | 51 | #endif /* _FLEX_ARRAY_H */ |
diff --git a/lib/flex_array.c b/lib/flex_array.c index e22d0e9776aa..1b03bb553410 100644 --- a/lib/flex_array.c +++ b/lib/flex_array.c | |||
@@ -291,3 +291,43 @@ void *flex_array_get(struct flex_array *fa, unsigned int element_nr) | |||
291 | } | 291 | } |
292 | return &part->elements[index_inside_part(fa, element_nr)]; | 292 | return &part->elements[index_inside_part(fa, element_nr)]; |
293 | } | 293 | } |
294 | |||
295 | static int part_is_free(struct flex_array_part *part) | ||
296 | { | ||
297 | int i; | ||
298 | |||
299 | for (i = 0; i < sizeof(struct flex_array_part); i++) | ||
300 | if (part->elements[i] != FLEX_ARRAY_FREE) | ||
301 | return 0; | ||
302 | return 1; | ||
303 | } | ||
304 | |||
305 | /** | ||
306 | * flex_array_shrink - free unused second-level pages | ||
307 | * | ||
308 | * Frees all second-level pages that consist solely of unused | ||
309 | * elements. Returns the number of pages freed. | ||
310 | * | ||
311 | * Locking must be provided by the caller. | ||
312 | */ | ||
313 | int flex_array_shrink(struct flex_array *fa) | ||
314 | { | ||
315 | struct flex_array_part *part; | ||
316 | int max_part = nr_base_part_ptrs(); | ||
317 | int part_nr; | ||
318 | int ret = 0; | ||
319 | |||
320 | if (elements_fit_in_base(fa)) | ||
321 | return ret; | ||
322 | for (part_nr = 0; part_nr < max_part; part_nr++) { | ||
323 | part = fa->parts[part_nr]; | ||
324 | if (!part) | ||
325 | continue; | ||
326 | if (part_is_free(part)) { | ||
327 | fa->parts[part_nr] = NULL; | ||
328 | kfree(part); | ||
329 | ret++; | ||
330 | } | ||
331 | } | ||
332 | return ret; | ||
333 | } | ||