/* * 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" /*-- Configurable parameters */ /* * Pages that compress to size greater than this are stored * uncompressed in memory. */ static const size_t max_zpage_size = PAGE_SIZE / 4 * 3; /* * NOTE: max_zpage_size must be less than or equal to: * ZS_MAX_ALLOC_SIZE. Otherwise, zs_malloc() would * always return failure. */ /*-- End of configurable params */ #define SECTOR_SHIFT 9 #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 { /* Page consists entirely of zeros */ ZRAM_SAME = ZRAM_FLAG_SHIFT, ZRAM_ACCESS, /* page is now accessed */ __NR_ZRAM_PAGEFLAGS, }; /*-- Data structures */ /* Allocated for each disk page */ struct zram_table_entry { union { unsigned long handle; unsigned long element; }; unsigned long value; }; 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 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_meta { struct zram_table_entry *table; struct zs_pool *mem_pool; }; struct zram { struct zram_meta *meta; 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 */ }; #endifOverall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Nitin Gupta | 105 | 48.17% | 8 | 25.81% |
| MinChan Kim | 39 | 17.89% | 7 | 22.58% |
| Sergey Senozhatsky | 26 | 11.93% | 7 | 22.58% |
| Weijie Yang | 13 | 5.96% | 1 | 3.23% |
| Jerome Marchand | 11 | 5.05% | 2 | 6.45% |
| Zhou Xian Rong | 11 | 5.05% | 1 | 3.23% |
| Jiang Liu | 7 | 3.21% | 1 | 3.23% |
| Robert Jennings | 3 | 1.38% | 1 | 3.23% |
| Chao Yu | 1 | 0.46% | 1 | 3.23% |
| Ganesh Mahendran | 1 | 0.46% | 1 | 3.23% |
| C yp | 1 | 0.46% | 1 | 3.23% |
| Total | 218 | 100.00% | 31 | 100.00% |