提交 6de8ab68 编写于 作者: L Lai Jiangshan 提交者: Linus Torvalds

lib: remove prio_heap

The prio_heap code is unused since commit 889ed9ce ("cgroup: remove
css_scan_tasks()").  It should be compiled out to shrink the binary
kernel size which can be done via introducing CONFIG_PRIO_HEAD or by
removing the code.

We can simply recover the code from git when needed, so it would be
better to remove it IMO.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: NTejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Acked-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Francesco Fusco <ffusco@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: George Spelvin <linux@horizon.com>
Cc: Mark Salter <msalter@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
上级 fec22908
#ifndef _LINUX_PRIO_HEAP_H
#define _LINUX_PRIO_HEAP_H
/*
* Simple insertion-only static-sized priority heap containing
* pointers, based on CLR, chapter 7
*/
#include <linux/gfp.h>
/**
* struct ptr_heap - simple static-sized priority heap
* @ptrs - pointer to data area
* @max - max number of elements that can be stored in @ptrs
* @size - current number of valid elements in @ptrs (in the range 0..@size-1
* @gt: comparison operator, which should implement "greater than"
*/
struct ptr_heap {
void **ptrs;
int max;
int size;
int (*gt)(void *, void *);
};
/**
* heap_init - initialize an empty heap with a given memory size
* @heap: the heap structure to be initialized
* @size: amount of memory to use in bytes
* @gfp_mask: mask to pass to kmalloc()
* @gt: comparison operator, which should implement "greater than"
*/
extern int heap_init(struct ptr_heap *heap, size_t size, gfp_t gfp_mask,
int (*gt)(void *, void *));
/**
* heap_free - release a heap's storage
* @heap: the heap structure whose data should be released
*/
void heap_free(struct ptr_heap *heap);
/**
* heap_insert - insert a value into the heap and return any overflowed value
* @heap: the heap to be operated on
* @p: the pointer to be inserted
*
* Attempts to insert the given value into the priority heap. If the
* heap is full prior to the insertion, then the resulting heap will
* consist of the smallest @max elements of the original heap and the
* new element; the greatest element will be removed from the heap and
* returned. Note that the returned element will be the new element
* (i.e. no change to the heap) if the new element is greater than all
* elements currently in the heap.
*/
extern void *heap_insert(struct ptr_heap *heap, void *p);
#endif /* _LINUX_PRIO_HEAP_H */
......@@ -11,7 +11,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
rbtree.o radix-tree.o dump_stack.o timerqueue.o\
idr.o int_sqrt.o extable.o \
sha1.o md5.o irq_regs.o reciprocal_div.o argv_split.o \
proportions.o flex_proportions.o prio_heap.o ratelimit.o show_mem.o \
proportions.o flex_proportions.o ratelimit.o show_mem.o \
is_single_threaded.o plist.o decompress.o kobject_uevent.o \
earlycpio.o
......
/*
* Simple insertion-only static-sized priority heap containing
* pointers, based on CLR, chapter 7
*/
#include <linux/slab.h>
#include <linux/prio_heap.h>
int heap_init(struct ptr_heap *heap, size_t size, gfp_t gfp_mask,
int (*gt)(void *, void *))
{
heap->ptrs = kmalloc(size, gfp_mask);
if (!heap->ptrs)
return -ENOMEM;
heap->size = 0;
heap->max = size / sizeof(void *);
heap->gt = gt;
return 0;
}
void heap_free(struct ptr_heap *heap)
{
kfree(heap->ptrs);
}
void *heap_insert(struct ptr_heap *heap, void *p)
{
void *res;
void **ptrs = heap->ptrs;
int pos;
if (heap->size < heap->max) {
/* Heap insertion */
pos = heap->size++;
while (pos > 0 && heap->gt(p, ptrs[(pos-1)/2])) {
ptrs[pos] = ptrs[(pos-1)/2];
pos = (pos-1)/2;
}
ptrs[pos] = p;
return NULL;
}
/* The heap is full, so something will have to be dropped */
/* If the new pointer is greater than the current max, drop it */
if (heap->gt(p, ptrs[0]))
return p;
/* Replace the current max and heapify */
res = ptrs[0];
ptrs[0] = p;
pos = 0;
while (1) {
int left = 2 * pos + 1;
int right = 2 * pos + 2;
int largest = pos;
if (left < heap->size && heap->gt(ptrs[left], p))
largest = left;
if (right < heap->size && heap->gt(ptrs[right], ptrs[largest]))
largest = right;
if (largest == pos)
break;
/* Push p down the heap one level and bump one up */
ptrs[pos] = ptrs[largest];
ptrs[largest] = p;
pos = largest;
}
return res;
}
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