4af5a2f770
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>
52 lines
1.3 KiB
C
52 lines
1.3 KiB
C
#ifndef _FLEX_ARRAY_H
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#define _FLEX_ARRAY_H
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#include <linux/types.h>
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#include <asm/page.h>
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#define FLEX_ARRAY_PART_SIZE PAGE_SIZE
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#define FLEX_ARRAY_BASE_SIZE PAGE_SIZE
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struct flex_array_part;
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/*
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* This is meant to replace cases where an array-like
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* structure has gotten too big to fit into kmalloc()
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* and the developer is getting tempted to use
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* vmalloc().
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*/
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struct flex_array {
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union {
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struct {
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int element_size;
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int total_nr_elements;
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struct flex_array_part *parts[];
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};
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/*
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* This little trick makes sure that
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* sizeof(flex_array) == PAGE_SIZE
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*/
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char padding[FLEX_ARRAY_BASE_SIZE];
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};
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};
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#define FLEX_ARRAY_INIT(size, total) { { {\
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.element_size = (size), \
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.total_nr_elements = (total), \
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} } }
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struct flex_array *flex_array_alloc(int element_size, unsigned int total,
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gfp_t flags);
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int flex_array_prealloc(struct flex_array *fa, unsigned int start,
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unsigned int end, gfp_t flags);
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void flex_array_free(struct flex_array *fa);
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void flex_array_free_parts(struct flex_array *fa);
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int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src,
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gfp_t flags);
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int flex_array_clear(struct flex_array *fa, unsigned int element_nr);
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void *flex_array_get(struct flex_array *fa, unsigned int element_nr);
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int flex_array_shrink(struct flex_array *fa);
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#endif /* _FLEX_ARRAY_H */
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