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129 lines
3.8 KiB
129 lines
3.8 KiB
/* |
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* Compressed RAM block device |
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* |
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* Copyright (C) 2008, 2009, 2010 Nitin Gupta |
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* 2012, 2013 Minchan Kim |
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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 licence 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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*/ |
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#ifndef _ZRAM_DRV_H_ |
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#define _ZRAM_DRV_H_ |
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#include <linux/rwsem.h> |
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#include <linux/zsmalloc.h> |
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#include <linux/crypto.h> |
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#include "zcomp.h" |
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#define SECTORS_PER_PAGE_SHIFT (PAGE_SHIFT - SECTOR_SHIFT) |
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#define SECTORS_PER_PAGE (1 << SECTORS_PER_PAGE_SHIFT) |
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#define ZRAM_LOGICAL_BLOCK_SHIFT 12 |
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#define ZRAM_LOGICAL_BLOCK_SIZE (1 << ZRAM_LOGICAL_BLOCK_SHIFT) |
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#define ZRAM_SECTOR_PER_LOGICAL_BLOCK \ |
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(1 << (ZRAM_LOGICAL_BLOCK_SHIFT - SECTOR_SHIFT)) |
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/* |
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* The lower ZRAM_FLAG_SHIFT bits of table.flags is for |
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* object size (excluding header), the higher bits is for |
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* zram_pageflags. |
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* |
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* zram is mainly used for memory efficiency so we want to keep memory |
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* footprint small so we can squeeze size and flags into a field. |
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* The lower ZRAM_FLAG_SHIFT bits is for object size (excluding header), |
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* the higher bits is for zram_pageflags. |
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*/ |
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#define ZRAM_FLAG_SHIFT 24 |
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/* Flags for zram pages (table[page_no].flags) */ |
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enum zram_pageflags { |
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/* zram slot is locked */ |
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ZRAM_LOCK = ZRAM_FLAG_SHIFT, |
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ZRAM_SAME, /* Page consists the same element */ |
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ZRAM_WB, /* page is stored on backing_device */ |
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ZRAM_UNDER_WB, /* page is under writeback */ |
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ZRAM_HUGE, /* Incompressible page */ |
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ZRAM_IDLE, /* not accessed page since last idle marking */ |
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__NR_ZRAM_PAGEFLAGS, |
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}; |
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/*-- Data structures */ |
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/* Allocated for each disk page */ |
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struct zram_table_entry { |
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union { |
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unsigned long handle; |
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unsigned long element; |
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}; |
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unsigned long flags; |
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#ifdef CONFIG_ZRAM_MEMORY_TRACKING |
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ktime_t ac_time; |
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#endif |
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}; |
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struct zram_stats { |
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atomic64_t compr_data_size; /* compressed size of pages stored */ |
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atomic64_t num_reads; /* failed + successful */ |
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atomic64_t num_writes; /* --do-- */ |
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atomic64_t failed_reads; /* can happen when memory is too low */ |
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atomic64_t failed_writes; /* can happen when memory is too low */ |
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atomic64_t invalid_io; /* non-page-aligned I/O requests */ |
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atomic64_t notify_free; /* no. of swap slot free notifications */ |
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atomic64_t same_pages; /* no. of same element filled pages */ |
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atomic64_t huge_pages; /* no. of huge pages */ |
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atomic64_t huge_pages_since; /* no. of huge pages since zram set up */ |
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atomic64_t pages_stored; /* no. of pages currently stored */ |
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atomic_long_t max_used_pages; /* no. of maximum pages stored */ |
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atomic64_t writestall; /* no. of write slow paths */ |
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atomic64_t miss_free; /* no. of missed free */ |
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#ifdef CONFIG_ZRAM_WRITEBACK |
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atomic64_t bd_count; /* no. of pages in backing device */ |
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atomic64_t bd_reads; /* no. of reads from backing device */ |
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atomic64_t bd_writes; /* no. of writes from backing device */ |
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#endif |
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}; |
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struct zram { |
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struct zram_table_entry *table; |
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struct zs_pool *mem_pool; |
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struct zcomp *comp; |
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struct gendisk *disk; |
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/* Prevent concurrent execution of device init */ |
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struct rw_semaphore init_lock; |
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/* |
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* the number of pages zram can consume for storing compressed data |
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*/ |
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unsigned long limit_pages; |
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struct zram_stats stats; |
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/* |
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* This is the limit on amount of *uncompressed* worth of data |
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* we can store in a disk. |
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*/ |
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u64 disksize; /* bytes */ |
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char compressor[CRYPTO_MAX_ALG_NAME]; |
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/* |
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* zram is claimed so open request will be failed |
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*/ |
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bool claim; /* Protected by disk->open_mutex */ |
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#ifdef CONFIG_ZRAM_WRITEBACK |
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struct file *backing_dev; |
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spinlock_t wb_limit_lock; |
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bool wb_limit_enable; |
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u64 bd_wb_limit; |
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struct block_device *bdev; |
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unsigned long *bitmap; |
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unsigned long nr_pages; |
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#endif |
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#ifdef CONFIG_ZRAM_MEMORY_TRACKING |
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struct dentry *debugfs_dir; |
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#endif |
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}; |
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#endif
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