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.
Unified · Split
| @@ -46,5 +46,6 @@ int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src, · 45 unmodified lines | |||
| 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 */ |
| @@ -291,3 +291,43 @@ void *flex_array_get(struct flex_array *fa, unsigned int element_nr) · 290 unmodified lines | |||
| 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 | } | ||