forked from luck/tmp_suning_uos_patched
staging: zsmalloc: zsmalloc memory allocation library
This patch creates a new memory allocation library named zsmalloc. NOTE: zsmalloc currently depends on SPARSEMEM for the MAX_PHYSMEM_BITS value needed to determine the format of the object handle. There may be a better way to do this. Feedback is welcome. Signed-off-by: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
17dd9f831a
commit
61989a80fb
11
drivers/staging/zsmalloc/Kconfig
Normal file
11
drivers/staging/zsmalloc/Kconfig
Normal file
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@ -0,0 +1,11 @@
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config ZSMALLOC
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tristate "Memory allocator for compressed pages"
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depends on SPARSEMEM
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default n
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help
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zsmalloc is a slab-based memory allocator designed to store
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compressed RAM pages. zsmalloc uses virtual memory mapping
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in order to reduce fragmentation. However, this results in a
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non-standard allocator interface where a handle, not a pointer, is
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returned by an alloc(). This handle must be mapped in order to
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access the allocated space.
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3
drivers/staging/zsmalloc/Makefile
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3
drivers/staging/zsmalloc/Makefile
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zsmalloc-y := zsmalloc-main.o
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obj-$(CONFIG_ZSMALLOC) += zsmalloc.o
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756
drivers/staging/zsmalloc/zsmalloc-main.c
Normal file
756
drivers/staging/zsmalloc/zsmalloc-main.c
Normal file
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@ -0,0 +1,756 @@
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/*
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* zsmalloc memory allocator
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*
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* Copyright (C) 2011 Nitin Gupta
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*
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* This code is released using a dual license strategy: BSD/GPL
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* You can choose the license that better fits your requirements.
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*
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* Released under the terms of 3-clause BSD License
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* Released under the terms of GNU General Public License Version 2.0
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*/
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#ifdef CONFIG_ZSMALLOC_DEBUG
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#define DEBUG
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#endif
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/bitops.h>
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#include <linux/errno.h>
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#include <linux/highmem.h>
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#include <linux/init.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <asm/tlbflush.h>
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#include <asm/pgtable.h>
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#include <linux/cpumask.h>
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#include <linux/cpu.h>
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#include "zsmalloc.h"
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#include "zsmalloc_int.h"
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/*
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* A zspage's class index and fullness group
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* are encoded in its (first)page->mapping
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*/
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#define CLASS_IDX_BITS 28
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#define FULLNESS_BITS 4
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#define CLASS_IDX_MASK ((1 << CLASS_IDX_BITS) - 1)
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#define FULLNESS_MASK ((1 << FULLNESS_BITS) - 1)
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/*
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* Object location (<PFN>, <obj_idx>) is encoded as
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* as single (void *) handle value.
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*
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* Note that object index <obj_idx> is relative to system
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* page <PFN> it is stored in, so for each sub-page belonging
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* to a zspage, obj_idx starts with 0.
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*/
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#define _PFN_BITS (MAX_PHYSMEM_BITS - PAGE_SHIFT)
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#define OBJ_INDEX_BITS (BITS_PER_LONG - _PFN_BITS)
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#define OBJ_INDEX_MASK ((_AC(1, UL) << OBJ_INDEX_BITS) - 1)
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/* per-cpu VM mapping areas for zspage accesses that cross page boundaries */
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static DEFINE_PER_CPU(struct mapping_area, zs_map_area);
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static int is_first_page(struct page *page)
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{
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return test_bit(PG_private, &page->flags);
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}
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static int is_last_page(struct page *page)
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{
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return test_bit(PG_private_2, &page->flags);
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}
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static void get_zspage_mapping(struct page *page, unsigned int *class_idx,
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enum fullness_group *fullness)
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{
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unsigned long m;
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BUG_ON(!is_first_page(page));
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m = (unsigned long)page->mapping;
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*fullness = m & FULLNESS_MASK;
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*class_idx = (m >> FULLNESS_BITS) & CLASS_IDX_MASK;
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}
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static void set_zspage_mapping(struct page *page, unsigned int class_idx,
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enum fullness_group fullness)
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{
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unsigned long m;
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BUG_ON(!is_first_page(page));
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m = ((class_idx & CLASS_IDX_MASK) << FULLNESS_BITS) |
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(fullness & FULLNESS_MASK);
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page->mapping = (struct address_space *)m;
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}
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static int get_size_class_index(int size)
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{
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int idx = 0;
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if (likely(size > ZS_MIN_ALLOC_SIZE))
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idx = DIV_ROUND_UP(size - ZS_MIN_ALLOC_SIZE,
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ZS_SIZE_CLASS_DELTA);
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return idx;
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}
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static enum fullness_group get_fullness_group(struct page *page)
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{
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int inuse, max_objects;
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enum fullness_group fg;
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BUG_ON(!is_first_page(page));
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inuse = page->inuse;
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max_objects = page->objects;
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if (inuse == 0)
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fg = ZS_EMPTY;
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else if (inuse == max_objects)
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fg = ZS_FULL;
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else if (inuse <= max_objects / fullness_threshold_frac)
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fg = ZS_ALMOST_EMPTY;
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else
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fg = ZS_ALMOST_FULL;
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return fg;
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}
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static void insert_zspage(struct page *page, struct size_class *class,
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enum fullness_group fullness)
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{
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struct page **head;
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BUG_ON(!is_first_page(page));
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if (fullness >= _ZS_NR_FULLNESS_GROUPS)
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return;
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head = &class->fullness_list[fullness];
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if (*head)
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list_add_tail(&page->lru, &(*head)->lru);
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*head = page;
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}
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static void remove_zspage(struct page *page, struct size_class *class,
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enum fullness_group fullness)
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{
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struct page **head;
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BUG_ON(!is_first_page(page));
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if (fullness >= _ZS_NR_FULLNESS_GROUPS)
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return;
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head = &class->fullness_list[fullness];
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BUG_ON(!*head);
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if (list_empty(&(*head)->lru))
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*head = NULL;
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else if (*head == page)
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*head = (struct page *)list_entry((*head)->lru.next,
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struct page, lru);
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list_del_init(&page->lru);
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}
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static enum fullness_group fix_fullness_group(struct zs_pool *pool,
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struct page *page)
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{
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int class_idx;
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struct size_class *class;
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enum fullness_group currfg, newfg;
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BUG_ON(!is_first_page(page));
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get_zspage_mapping(page, &class_idx, &currfg);
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newfg = get_fullness_group(page);
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if (newfg == currfg)
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goto out;
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class = &pool->size_class[class_idx];
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remove_zspage(page, class, currfg);
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insert_zspage(page, class, newfg);
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set_zspage_mapping(page, class_idx, newfg);
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out:
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return newfg;
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}
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/*
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* We have to decide on how many pages to link together
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* to form a zspage for each size class. This is important
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* to reduce wastage due to unusable space left at end of
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* each zspage which is given as:
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* wastage = Zp - Zp % size_class
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* where Zp = zspage size = k * PAGE_SIZE where k = 1, 2, ...
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*
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* For example, for size class of 3/8 * PAGE_SIZE, we should
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* link together 3 PAGE_SIZE sized pages to form a zspage
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* since then we can perfectly fit in 8 such objects.
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*/
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static int get_zspage_order(int class_size)
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{
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int i, max_usedpc = 0;
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/* zspage order which gives maximum used size per KB */
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int max_usedpc_order = 1;
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for (i = 1; i <= max_zspage_order; i++) {
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int zspage_size;
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int waste, usedpc;
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zspage_size = i * PAGE_SIZE;
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waste = zspage_size % class_size;
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usedpc = (zspage_size - waste) * 100 / zspage_size;
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if (usedpc > max_usedpc) {
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max_usedpc = usedpc;
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max_usedpc_order = i;
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}
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}
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return max_usedpc_order;
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}
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/*
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* A single 'zspage' is composed of many system pages which are
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* linked together using fields in struct page. This function finds
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* the first/head page, given any component page of a zspage.
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*/
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static struct page *get_first_page(struct page *page)
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{
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if (is_first_page(page))
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return page;
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else
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return page->first_page;
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}
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static struct page *get_next_page(struct page *page)
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{
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struct page *next;
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if (is_last_page(page))
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next = NULL;
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else if (is_first_page(page))
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next = (struct page *)page->private;
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else
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next = list_entry(page->lru.next, struct page, lru);
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return next;
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}
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/* Encode <page, obj_idx> as a single handle value */
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static void *obj_location_to_handle(struct page *page, unsigned long obj_idx)
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{
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unsigned long handle;
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if (!page) {
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BUG_ON(obj_idx);
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return NULL;
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}
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handle = page_to_pfn(page) << OBJ_INDEX_BITS;
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handle |= (obj_idx & OBJ_INDEX_MASK);
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return (void *)handle;
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}
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/* Decode <page, obj_idx> pair from the given object handle */
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static void obj_handle_to_location(void *handle, struct page **page,
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unsigned long *obj_idx)
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{
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unsigned long hval = (unsigned long)handle;
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*page = pfn_to_page(hval >> OBJ_INDEX_BITS);
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*obj_idx = hval & OBJ_INDEX_MASK;
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}
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static unsigned long obj_idx_to_offset(struct page *page,
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unsigned long obj_idx, int class_size)
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{
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unsigned long off = 0;
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if (!is_first_page(page))
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off = page->index;
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return off + obj_idx * class_size;
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}
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static void free_zspage(struct page *first_page)
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{
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struct page *nextp, *tmp;
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BUG_ON(!is_first_page(first_page));
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BUG_ON(first_page->inuse);
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nextp = (struct page *)page_private(first_page);
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clear_bit(PG_private, &first_page->flags);
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clear_bit(PG_private_2, &first_page->flags);
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set_page_private(first_page, 0);
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first_page->mapping = NULL;
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first_page->freelist = NULL;
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reset_page_mapcount(first_page);
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__free_page(first_page);
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/* zspage with only 1 system page */
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if (!nextp)
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return;
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list_for_each_entry_safe(nextp, tmp, &nextp->lru, lru) {
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list_del(&nextp->lru);
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clear_bit(PG_private_2, &nextp->flags);
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nextp->index = 0;
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__free_page(nextp);
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}
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}
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/* Initialize a newly allocated zspage */
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static void init_zspage(struct page *first_page, struct size_class *class)
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{
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unsigned long off = 0;
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struct page *page = first_page;
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BUG_ON(!is_first_page(first_page));
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while (page) {
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struct page *next_page;
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struct link_free *link;
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unsigned int i, objs_on_page;
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/*
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* page->index stores offset of first object starting
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* in the page. For the first page, this is always 0,
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* so we use first_page->index (aka ->freelist) to store
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* head of corresponding zspage's freelist.
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*/
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if (page != first_page)
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page->index = off;
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link = (struct link_free *)kmap_atomic(page) +
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off / sizeof(*link);
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objs_on_page = (PAGE_SIZE - off) / class->size;
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for (i = 1; i <= objs_on_page; i++) {
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off += class->size;
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if (off < PAGE_SIZE) {
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link->next = obj_location_to_handle(page, i);
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link += class->size / sizeof(*link);
|
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}
|
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}
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|
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/*
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* We now come to the last (full or partial) object on this
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* page, which must point to the first object on the next
|
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* page (if present)
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*/
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next_page = get_next_page(page);
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link->next = obj_location_to_handle(next_page, 0);
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kunmap_atomic(link);
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page = next_page;
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off = (off + class->size) % PAGE_SIZE;
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}
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}
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|
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/*
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* Allocate a zspage for the given size class
|
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*/
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static struct page *alloc_zspage(struct size_class *class, gfp_t flags)
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{
|
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int i, error;
|
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struct page *first_page = NULL;
|
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|
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/*
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* Allocate individual pages and link them together as:
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* 1. first page->private = first sub-page
|
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* 2. all sub-pages are linked together using page->lru
|
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* 3. each sub-page is linked to the first page using page->first_page
|
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*
|
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* For each size class, First/Head pages are linked together using
|
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* page->lru. Also, we set PG_private to identify the first page
|
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* (i.e. no other sub-page has this flag set) and PG_private_2 to
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* identify the last page.
|
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*/
|
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error = -ENOMEM;
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for (i = 0; i < class->zspage_order; i++) {
|
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struct page *page, *prev_page;
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|
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page = alloc_page(flags);
|
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if (!page)
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goto cleanup;
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|
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INIT_LIST_HEAD(&page->lru);
|
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if (i == 0) { /* first page */
|
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set_bit(PG_private, &page->flags);
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set_page_private(page, 0);
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first_page = page;
|
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first_page->inuse = 0;
|
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}
|
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if (i == 1)
|
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first_page->private = (unsigned long)page;
|
||||
if (i >= 1)
|
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page->first_page = first_page;
|
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if (i >= 2)
|
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list_add(&page->lru, &prev_page->lru);
|
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if (i == class->zspage_order - 1) /* last page */
|
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set_bit(PG_private_2, &page->flags);
|
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|
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prev_page = page;
|
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}
|
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|
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init_zspage(first_page, class);
|
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|
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first_page->freelist = obj_location_to_handle(first_page, 0);
|
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/* Maximum number of objects we can store in this zspage */
|
||||
first_page->objects = class->zspage_order * PAGE_SIZE / class->size;
|
||||
|
||||
error = 0; /* Success */
|
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|
||||
cleanup:
|
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if (unlikely(error) && first_page) {
|
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free_zspage(first_page);
|
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first_page = NULL;
|
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}
|
||||
|
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return first_page;
|
||||
}
|
||||
|
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static struct page *find_get_zspage(struct size_class *class)
|
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{
|
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int i;
|
||||
struct page *page;
|
||||
|
||||
for (i = 0; i < _ZS_NR_FULLNESS_GROUPS; i++) {
|
||||
page = class->fullness_list[i];
|
||||
if (page)
|
||||
break;
|
||||
}
|
||||
|
||||
return page;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* If this becomes a separate module, register zs_init() with
|
||||
* module_init(), zs_exit with module_exit(), and remove zs_initialized
|
||||
*/
|
||||
static int zs_initialized;
|
||||
|
||||
static int zs_cpu_notifier(struct notifier_block *nb, unsigned long action,
|
||||
void *pcpu)
|
||||
{
|
||||
int cpu = (long)pcpu;
|
||||
struct mapping_area *area;
|
||||
|
||||
switch (action) {
|
||||
case CPU_UP_PREPARE:
|
||||
area = &per_cpu(zs_map_area, cpu);
|
||||
if (area->vm)
|
||||
break;
|
||||
area->vm = alloc_vm_area(2 * PAGE_SIZE, area->vm_ptes);
|
||||
if (!area->vm)
|
||||
return notifier_from_errno(-ENOMEM);
|
||||
break;
|
||||
case CPU_DEAD:
|
||||
case CPU_UP_CANCELED:
|
||||
area = &per_cpu(zs_map_area, cpu);
|
||||
if (area->vm)
|
||||
free_vm_area(area->vm);
|
||||
area->vm = NULL;
|
||||
break;
|
||||
}
|
||||
|
||||
return NOTIFY_OK;
|
||||
}
|
||||
|
||||
static struct notifier_block zs_cpu_nb = {
|
||||
.notifier_call = zs_cpu_notifier
|
||||
};
|
||||
|
||||
static void zs_exit(void)
|
||||
{
|
||||
int cpu;
|
||||
|
||||
for_each_online_cpu(cpu)
|
||||
zs_cpu_notifier(NULL, CPU_DEAD, (void *)(long)cpu);
|
||||
unregister_cpu_notifier(&zs_cpu_nb);
|
||||
}
|
||||
|
||||
static int zs_init(void)
|
||||
{
|
||||
int cpu, ret;
|
||||
|
||||
register_cpu_notifier(&zs_cpu_nb);
|
||||
for_each_online_cpu(cpu) {
|
||||
ret = zs_cpu_notifier(NULL, CPU_UP_PREPARE, (void *)(long)cpu);
|
||||
if (notifier_to_errno(ret))
|
||||
goto fail;
|
||||
}
|
||||
return 0;
|
||||
fail:
|
||||
zs_exit();
|
||||
return notifier_to_errno(ret);
|
||||
}
|
||||
|
||||
struct zs_pool *zs_create_pool(const char *name, gfp_t flags)
|
||||
{
|
||||
int i, error, ovhd_size;
|
||||
struct zs_pool *pool;
|
||||
|
||||
if (!name)
|
||||
return NULL;
|
||||
|
||||
ovhd_size = roundup(sizeof(*pool), PAGE_SIZE);
|
||||
pool = kzalloc(ovhd_size, GFP_KERNEL);
|
||||
if (!pool)
|
||||
return NULL;
|
||||
|
||||
for (i = 0; i < ZS_SIZE_CLASSES; i++) {
|
||||
int size;
|
||||
struct size_class *class;
|
||||
|
||||
size = ZS_MIN_ALLOC_SIZE + i * ZS_SIZE_CLASS_DELTA;
|
||||
if (size > ZS_MAX_ALLOC_SIZE)
|
||||
size = ZS_MAX_ALLOC_SIZE;
|
||||
|
||||
class = &pool->size_class[i];
|
||||
class->size = size;
|
||||
class->index = i;
|
||||
spin_lock_init(&class->lock);
|
||||
class->zspage_order = get_zspage_order(size);
|
||||
|
||||
}
|
||||
|
||||
/*
|
||||
* If this becomes a separate module, register zs_init with
|
||||
* module_init, and remove this block
|
||||
*/
|
||||
if (!zs_initialized) {
|
||||
error = zs_init();
|
||||
if (error)
|
||||
goto cleanup;
|
||||
zs_initialized = 1;
|
||||
}
|
||||
|
||||
pool->flags = flags;
|
||||
pool->name = name;
|
||||
|
||||
error = 0; /* Success */
|
||||
|
||||
cleanup:
|
||||
if (error) {
|
||||
zs_destroy_pool(pool);
|
||||
pool = NULL;
|
||||
}
|
||||
|
||||
return pool;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(zs_create_pool);
|
||||
|
||||
void zs_destroy_pool(struct zs_pool *pool)
|
||||
{
|
||||
int i;
|
||||
|
||||
for (i = 0; i < ZS_SIZE_CLASSES; i++) {
|
||||
int fg;
|
||||
struct size_class *class = &pool->size_class[i];
|
||||
|
||||
for (fg = 0; fg < _ZS_NR_FULLNESS_GROUPS; fg++) {
|
||||
if (class->fullness_list[fg]) {
|
||||
pr_info("Freeing non-empty class with size "
|
||||
"%db, fullness group %d\n",
|
||||
class->size, fg);
|
||||
}
|
||||
}
|
||||
}
|
||||
kfree(pool);
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(zs_destroy_pool);
|
||||
|
||||
/**
|
||||
* zs_malloc - Allocate block of given size from pool.
|
||||
* @pool: pool to allocate from
|
||||
* @size: size of block to allocate
|
||||
* @page: page no. that holds the object
|
||||
* @offset: location of object within page
|
||||
*
|
||||
* On success, <page, offset> identifies block allocated
|
||||
* and 0 is returned. On failure, <page, offset> is set to
|
||||
* 0 and -ENOMEM is returned.
|
||||
*
|
||||
* Allocation requests with size > ZS_MAX_ALLOC_SIZE will fail.
|
||||
*/
|
||||
void *zs_malloc(struct zs_pool *pool, size_t size)
|
||||
{
|
||||
void *obj;
|
||||
struct link_free *link;
|
||||
int class_idx;
|
||||
struct size_class *class;
|
||||
|
||||
struct page *first_page, *m_page;
|
||||
unsigned long m_objidx, m_offset;
|
||||
|
||||
if (unlikely(!size || size > ZS_MAX_ALLOC_SIZE))
|
||||
return NULL;
|
||||
|
||||
class_idx = get_size_class_index(size);
|
||||
class = &pool->size_class[class_idx];
|
||||
BUG_ON(class_idx != class->index);
|
||||
|
||||
spin_lock(&class->lock);
|
||||
first_page = find_get_zspage(class);
|
||||
|
||||
if (!first_page) {
|
||||
spin_unlock(&class->lock);
|
||||
first_page = alloc_zspage(class, pool->flags);
|
||||
if (unlikely(!first_page))
|
||||
return NULL;
|
||||
|
||||
set_zspage_mapping(first_page, class->index, ZS_EMPTY);
|
||||
spin_lock(&class->lock);
|
||||
class->pages_allocated += class->zspage_order;
|
||||
}
|
||||
|
||||
obj = first_page->freelist;
|
||||
obj_handle_to_location(obj, &m_page, &m_objidx);
|
||||
m_offset = obj_idx_to_offset(m_page, m_objidx, class->size);
|
||||
|
||||
link = (struct link_free *)kmap_atomic(m_page) +
|
||||
m_offset / sizeof(*link);
|
||||
first_page->freelist = link->next;
|
||||
memset(link, POISON_INUSE, sizeof(*link));
|
||||
kunmap_atomic(link);
|
||||
|
||||
first_page->inuse++;
|
||||
/* Now move the zspage to another fullness group, if required */
|
||||
fix_fullness_group(pool, first_page);
|
||||
spin_unlock(&class->lock);
|
||||
|
||||
return obj;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(zs_malloc);
|
||||
|
||||
void zs_free(struct zs_pool *pool, void *obj)
|
||||
{
|
||||
struct link_free *link;
|
||||
struct page *first_page, *f_page;
|
||||
unsigned long f_objidx, f_offset;
|
||||
|
||||
int class_idx;
|
||||
struct size_class *class;
|
||||
enum fullness_group fullness;
|
||||
|
||||
if (unlikely(!obj))
|
||||
return;
|
||||
|
||||
obj_handle_to_location(obj, &f_page, &f_objidx);
|
||||
first_page = get_first_page(f_page);
|
||||
|
||||
get_zspage_mapping(first_page, &class_idx, &fullness);
|
||||
class = &pool->size_class[class_idx];
|
||||
f_offset = obj_idx_to_offset(f_page, f_objidx, class->size);
|
||||
|
||||
spin_lock(&class->lock);
|
||||
|
||||
/* Insert this object in containing zspage's freelist */
|
||||
link = (struct link_free *)((unsigned char *)kmap_atomic(f_page)
|
||||
+ f_offset);
|
||||
link->next = first_page->freelist;
|
||||
kunmap_atomic(link);
|
||||
first_page->freelist = obj;
|
||||
|
||||
first_page->inuse--;
|
||||
fullness = fix_fullness_group(pool, first_page);
|
||||
|
||||
if (fullness == ZS_EMPTY)
|
||||
class->pages_allocated -= class->zspage_order;
|
||||
|
||||
spin_unlock(&class->lock);
|
||||
|
||||
if (fullness == ZS_EMPTY)
|
||||
free_zspage(first_page);
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(zs_free);
|
||||
|
||||
void *zs_map_object(struct zs_pool *pool, void *handle)
|
||||
{
|
||||
struct page *page;
|
||||
unsigned long obj_idx, off;
|
||||
|
||||
unsigned int class_idx;
|
||||
enum fullness_group fg;
|
||||
struct size_class *class;
|
||||
struct mapping_area *area;
|
||||
|
||||
BUG_ON(!handle);
|
||||
|
||||
obj_handle_to_location(handle, &page, &obj_idx);
|
||||
get_zspage_mapping(get_first_page(page), &class_idx, &fg);
|
||||
class = &pool->size_class[class_idx];
|
||||
off = obj_idx_to_offset(page, obj_idx, class->size);
|
||||
|
||||
area = &get_cpu_var(zs_map_area);
|
||||
if (off + class->size <= PAGE_SIZE) {
|
||||
/* this object is contained entirely within a page */
|
||||
area->vm_addr = kmap_atomic(page);
|
||||
} else {
|
||||
/* this object spans two pages */
|
||||
struct page *nextp;
|
||||
|
||||
nextp = get_next_page(page);
|
||||
BUG_ON(!nextp);
|
||||
|
||||
|
||||
set_pte(area->vm_ptes[0], mk_pte(page, PAGE_KERNEL));
|
||||
set_pte(area->vm_ptes[1], mk_pte(nextp, PAGE_KERNEL));
|
||||
|
||||
/* We pre-allocated VM area so mapping can never fail */
|
||||
area->vm_addr = area->vm->addr;
|
||||
}
|
||||
|
||||
return area->vm_addr + off;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(zs_map_object);
|
||||
|
||||
void zs_unmap_object(struct zs_pool *pool, void *handle)
|
||||
{
|
||||
struct page *page;
|
||||
unsigned long obj_idx, off;
|
||||
|
||||
unsigned int class_idx;
|
||||
enum fullness_group fg;
|
||||
struct size_class *class;
|
||||
struct mapping_area *area;
|
||||
|
||||
BUG_ON(!handle);
|
||||
|
||||
obj_handle_to_location(handle, &page, &obj_idx);
|
||||
get_zspage_mapping(get_first_page(page), &class_idx, &fg);
|
||||
class = &pool->size_class[class_idx];
|
||||
off = obj_idx_to_offset(page, obj_idx, class->size);
|
||||
|
||||
area = &__get_cpu_var(zs_map_area);
|
||||
if (off + class->size <= PAGE_SIZE) {
|
||||
kunmap_atomic(area->vm_addr);
|
||||
} else {
|
||||
set_pte(area->vm_ptes[0], __pte(0));
|
||||
set_pte(area->vm_ptes[1], __pte(0));
|
||||
__flush_tlb_one((unsigned long)area->vm_addr);
|
||||
__flush_tlb_one((unsigned long)area->vm_addr + PAGE_SIZE);
|
||||
}
|
||||
put_cpu_var(zs_map_area);
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(zs_unmap_object);
|
||||
|
||||
u64 zs_get_total_size_bytes(struct zs_pool *pool)
|
||||
{
|
||||
int i;
|
||||
u64 npages = 0;
|
||||
|
||||
for (i = 0; i < ZS_SIZE_CLASSES; i++)
|
||||
npages += pool->size_class[i].pages_allocated;
|
||||
|
||||
return npages << PAGE_SHIFT;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(zs_get_total_size_bytes);
|
31
drivers/staging/zsmalloc/zsmalloc.h
Normal file
31
drivers/staging/zsmalloc/zsmalloc.h
Normal file
|
@ -0,0 +1,31 @@
|
|||
/*
|
||||
* zsmalloc memory allocator
|
||||
*
|
||||
* Copyright (C) 2011 Nitin Gupta
|
||||
*
|
||||
* This code is released using a dual license strategy: BSD/GPL
|
||||
* You can choose the license that better fits your requirements.
|
||||
*
|
||||
* Released under the terms of 3-clause BSD License
|
||||
* Released under the terms of GNU General Public License Version 2.0
|
||||
*/
|
||||
|
||||
#ifndef _ZS_MALLOC_H_
|
||||
#define _ZS_MALLOC_H_
|
||||
|
||||
#include <linux/types.h>
|
||||
|
||||
struct zs_pool;
|
||||
|
||||
struct zs_pool *zs_create_pool(const char *name, gfp_t flags);
|
||||
void zs_destroy_pool(struct zs_pool *pool);
|
||||
|
||||
void *zs_malloc(struct zs_pool *pool, size_t size);
|
||||
void zs_free(struct zs_pool *pool, void *obj);
|
||||
|
||||
void *zs_map_object(struct zs_pool *pool, void *handle);
|
||||
void zs_unmap_object(struct zs_pool *pool, void *handle);
|
||||
|
||||
u64 zs_get_total_size_bytes(struct zs_pool *pool);
|
||||
|
||||
#endif
|
126
drivers/staging/zsmalloc/zsmalloc_int.h
Normal file
126
drivers/staging/zsmalloc/zsmalloc_int.h
Normal file
|
@ -0,0 +1,126 @@
|
|||
/*
|
||||
* zsmalloc memory allocator
|
||||
*
|
||||
* Copyright (C) 2011 Nitin Gupta
|
||||
*
|
||||
* This code is released using a dual license strategy: BSD/GPL
|
||||
* You can choose the license that better fits your requirements.
|
||||
*
|
||||
* Released under the terms of 3-clause BSD License
|
||||
* Released under the terms of GNU General Public License Version 2.0
|
||||
*/
|
||||
|
||||
#ifndef _ZS_MALLOC_INT_H_
|
||||
#define _ZS_MALLOC_INT_H_
|
||||
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/spinlock.h>
|
||||
#include <linux/types.h>
|
||||
|
||||
/*
|
||||
* This must be power of 2 and greater than of equal to sizeof(link_free).
|
||||
* These two conditions ensure that any 'struct link_free' itself doesn't
|
||||
* span more than 1 page which avoids complex case of mapping 2 pages simply
|
||||
* to restore link_free pointer values.
|
||||
*/
|
||||
#define ZS_ALIGN 8
|
||||
|
||||
/* ZS_MIN_ALLOC_SIZE must be multiple of ZS_ALIGN */
|
||||
#define ZS_MIN_ALLOC_SIZE 32
|
||||
#define ZS_MAX_ALLOC_SIZE PAGE_SIZE
|
||||
|
||||
/*
|
||||
* On systems with 4K page size, this gives 254 size classes! There is a
|
||||
* trader-off here:
|
||||
* - Large number of size classes is potentially wasteful as free page are
|
||||
* spread across these classes
|
||||
* - Small number of size classes causes large internal fragmentation
|
||||
* - Probably its better to use specific size classes (empirically
|
||||
* determined). NOTE: all those class sizes must be set as multiple of
|
||||
* ZS_ALIGN to make sure link_free itself never has to span 2 pages.
|
||||
*
|
||||
* ZS_MIN_ALLOC_SIZE and ZS_SIZE_CLASS_DELTA must be multiple of ZS_ALIGN
|
||||
* (reason above)
|
||||
*/
|
||||
#define ZS_SIZE_CLASS_DELTA 16
|
||||
#define ZS_SIZE_CLASSES ((ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE) / \
|
||||
ZS_SIZE_CLASS_DELTA + 1)
|
||||
|
||||
/*
|
||||
* A single 'zspage' is composed of N discontiguous 0-order (single) pages.
|
||||
* This defines upper limit on N.
|
||||
*/
|
||||
static const int max_zspage_order = 4;
|
||||
|
||||
/*
|
||||
* We do not maintain any list for completely empty or full pages
|
||||
*/
|
||||
enum fullness_group {
|
||||
ZS_ALMOST_FULL,
|
||||
ZS_ALMOST_EMPTY,
|
||||
_ZS_NR_FULLNESS_GROUPS,
|
||||
|
||||
ZS_EMPTY,
|
||||
ZS_FULL
|
||||
};
|
||||
|
||||
/*
|
||||
* We assign a page to ZS_ALMOST_EMPTY fullness group when:
|
||||
* n <= N / f, where
|
||||
* n = number of allocated objects
|
||||
* N = total number of objects zspage can store
|
||||
* f = 1/fullness_threshold_frac
|
||||
*
|
||||
* Similarly, we assign zspage to:
|
||||
* ZS_ALMOST_FULL when n > N / f
|
||||
* ZS_EMPTY when n == 0
|
||||
* ZS_FULL when n == N
|
||||
*
|
||||
* (see: fix_fullness_group())
|
||||
*/
|
||||
static const int fullness_threshold_frac = 4;
|
||||
|
||||
struct mapping_area {
|
||||
struct vm_struct *vm;
|
||||
pte_t *vm_ptes[2];
|
||||
char *vm_addr;
|
||||
};
|
||||
|
||||
struct size_class {
|
||||
/*
|
||||
* Size of objects stored in this class. Must be multiple
|
||||
* of ZS_ALIGN.
|
||||
*/
|
||||
int size;
|
||||
unsigned int index;
|
||||
|
||||
/* Number of PAGE_SIZE sized pages to combine to form a 'zspage' */
|
||||
int zspage_order;
|
||||
|
||||
spinlock_t lock;
|
||||
|
||||
/* stats */
|
||||
u64 pages_allocated;
|
||||
|
||||
struct page *fullness_list[_ZS_NR_FULLNESS_GROUPS];
|
||||
};
|
||||
|
||||
/*
|
||||
* Placed within free objects to form a singly linked list.
|
||||
* For every zspage, first_page->freelist gives head of this list.
|
||||
*
|
||||
* This must be power of 2 and less than or equal to ZS_ALIGN
|
||||
*/
|
||||
struct link_free {
|
||||
/* Handle of next free chunk (encodes <PFN, obj_idx>) */
|
||||
void *next;
|
||||
};
|
||||
|
||||
struct zs_pool {
|
||||
struct size_class size_class[ZS_SIZE_CLASSES];
|
||||
|
||||
gfp_t flags; /* allocation flags used when growing pool */
|
||||
const char *name;
|
||||
};
|
||||
|
||||
#endif
|
Loading…
Reference in New Issue
Block a user