Release 4.18 drivers/block/zram/zram_drv.h
/*
* Compressed RAM block device
*
* Copyright (C) 2008, 2009, 2010 Nitin Gupta
* 2012, 2013 Minchan Kim
*
* This code is released using a dual license strategy: BSD/GPL
* You can choose the licence 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 _ZRAM_DRV_H_
#define _ZRAM_DRV_H_
#include <linux/rwsem.h>
#include <linux/zsmalloc.h>
#include <linux/crypto.h>
#include "zcomp.h"
#define SECTORS_PER_PAGE_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
#define SECTORS_PER_PAGE (1 << SECTORS_PER_PAGE_SHIFT)
#define ZRAM_LOGICAL_BLOCK_SHIFT 12
#define ZRAM_LOGICAL_BLOCK_SIZE (1 << ZRAM_LOGICAL_BLOCK_SHIFT)
#define ZRAM_SECTOR_PER_LOGICAL_BLOCK \
(1 << (ZRAM_LOGICAL_BLOCK_SHIFT - SECTOR_SHIFT))
/*
* The lower ZRAM_FLAG_SHIFT bits of table.value is for
* object size (excluding header), the higher bits is for
* zram_pageflags.
*
* zram is mainly used for memory efficiency so we want to keep memory
* footprint small so we can squeeze size and flags into a field.
* The lower ZRAM_FLAG_SHIFT bits is for object size (excluding header),
* the higher bits is for zram_pageflags.
*/
#define ZRAM_FLAG_SHIFT 24
/* Flags for zram pages (table[page_no].value) */
enum zram_pageflags {
/* zram slot is locked */
ZRAM_LOCK = ZRAM_FLAG_SHIFT,
ZRAM_SAME, /* Page consists the same element */
ZRAM_WB, /* page is stored on backing_device */
ZRAM_HUGE, /* Incompressible page */
__NR_ZRAM_PAGEFLAGS,
};
/*-- Data structures */
/* Allocated for each disk page */
struct zram_table_entry {
union {
unsigned long handle;
unsigned long element;
};
unsigned long value;
#ifdef CONFIG_ZRAM_MEMORY_TRACKING
ktime_t ac_time;
#endif
};
struct zram_stats {
atomic64_t compr_data_size; /* compressed size of pages stored */
atomic64_t num_reads; /* failed + successful */
atomic64_t num_writes; /* --do-- */
atomic64_t failed_reads; /* can happen when memory is too low */
atomic64_t failed_writes; /* can happen when memory is too low */
atomic64_t invalid_io; /* non-page-aligned I/O requests */
atomic64_t notify_free; /* no. of swap slot free notifications */
atomic64_t same_pages; /* no. of same element filled pages */
atomic64_t huge_pages; /* no. of huge pages */
atomic64_t pages_stored; /* no. of pages currently stored */
atomic_long_t max_used_pages; /* no. of maximum pages stored */
atomic64_t writestall; /* no. of write slow paths */
};
struct zram {
struct zram_table_entry *table;
struct zs_pool *mem_pool;
struct zcomp *comp;
struct gendisk *disk;
/* Prevent concurrent execution of device init */
struct rw_semaphore init_lock;
/*
* the number of pages zram can consume for storing compressed data
*/
unsigned long limit_pages;
struct zram_stats stats;
/*
* This is the limit on amount of *uncompressed* worth of data
* we can store in a disk.
*/
u64 disksize; /* bytes */
char compressor[CRYPTO_MAX_ALG_NAME];
/*
* zram is claimed so open request will be failed
*/
bool claim; /* Protected by bdev->bd_mutex */
#ifdef CONFIG_ZRAM_WRITEBACK
struct file *backing_dev;
struct block_device *bdev;
unsigned int old_block_size;
unsigned long *bitmap;
unsigned long nr_pages;
spinlock_t bitmap_lock;
#endif
#ifdef CONFIG_ZRAM_MEMORY_TRACKING
struct dentry *debugfs_dir;
#endif
};
#endif
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| MinChan Kim | 91 | 36.69% | 14 | 40.00% |
| Nitin Gupta | 86 | 34.68% | 6 | 17.14% |
| Sergey Senozhatsky | 26 | 10.48% | 7 | 20.00% |
| Weijie Yang | 12 | 4.84% | 1 | 2.86% |
| Jerome Marchand | 11 | 4.44% | 2 | 5.71% |
| Zhou Xian Rong | 10 | 4.03% | 1 | 2.86% |
| Jiang Liu | 7 | 2.82% | 1 | 2.86% |
| Robert Jennings | 3 | 1.21% | 1 | 2.86% |
| C yp | 1 | 0.40% | 1 | 2.86% |
| Chao Yu | 1 | 0.40% | 1 | 2.86% |
| Total | 248 | 100.00% | 35 | 100.00% |
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