| Kconfig (35e669e1a254e8b60d4a8983205b383666cc01ca) | Kconfig (db2aa7fd15e857891cefbada8348c8d938c7a2bc) |
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| 1# 2# Configuration for initramfs 3# 4 5config INITRAMFS_SOURCE 6 string "Initramfs source file(s)" 7 default "" 8 help --- 85 unchanged lines hidden (view full) --- 94 bool "Support initial ramdisks compressed using LZ4" 95 default y 96 depends on BLK_DEV_INITRD 97 select DECOMPRESS_LZ4 98 help 99 Support loading of a LZ4 encoded initial ramdisk or cpio buffer 100 If unsure, say N. 101 | 1# 2# Configuration for initramfs 3# 4 5config INITRAMFS_SOURCE 6 string "Initramfs source file(s)" 7 default "" 8 help --- 85 unchanged lines hidden (view full) --- 94 bool "Support initial ramdisks compressed using LZ4" 95 default y 96 depends on BLK_DEV_INITRD 97 select DECOMPRESS_LZ4 98 help 99 Support loading of a LZ4 encoded initial ramdisk or cpio buffer 100 If unsure, say N. 101 |
| 102choice 103 prompt "Built-in initramfs compression mode" 104 depends on INITRAMFS_SOURCE!="" 105 optional 106 help 107 This option allows you to decide by which algorithm the builtin 108 initramfs will be compressed. Several compression algorithms are 109 available, which differ in efficiency, compression and 110 decompression speed. Compression speed is only relevant 111 when building a kernel. Decompression speed is relevant at 112 each boot. Also the memory usage during decompression may become 113 relevant on memory constrained systems. This is usually based on the 114 dictionary size of the algorithm with algorithms like XZ and LZMA 115 featuring large dictionary sizes. 116 117 High compression options are mostly useful for users who are 118 low on RAM, since it reduces the memory consumption during 119 boot. 120 121 Keep in mind that your build system needs to provide the appropriate 122 compression tool to compress the generated initram cpio file for 123 embedding. 124 125 If in doubt, select 'None' 126 127config INITRAMFS_COMPRESSION_NONE 128 bool "None" 129 help 130 Do not compress the built-in initramfs at all. This may sound wasteful 131 in space, but, you should be aware that the built-in initramfs will be 132 compressed at a later stage anyways along with the rest of the kernel, 133 on those architectures that support this. However, not compressing the 134 initramfs may lead to slightly higher memory consumption during a 135 short time at boot, while both the cpio image and the unpacked 136 filesystem image will be present in memory simultaneously 137 138config INITRAMFS_COMPRESSION_GZIP 139 bool "Gzip" 140 depends on RD_GZIP 141 help 142 Use the old and well tested gzip compression algorithm. Gzip provides 143 a good balance between compression ratio and decompression speed and 144 has a reasonable compression speed. It is also more likely to be 145 supported by your build system as the gzip tool is present by default 146 on most distros. 147 148config INITRAMFS_COMPRESSION_BZIP2 149 bool "Bzip2" 150 depends on RD_BZIP2 151 help 152 It's compression ratio and speed is intermediate. Decompression speed 153 is slowest among the choices. The initramfs size is about 10% smaller 154 with bzip2, in comparison to gzip. Bzip2 uses a large amount of 155 memory. For modern kernels you will need at least 8MB RAM or more for 156 booting. 157 158 If you choose this, keep in mind that you need to have the bzip2 tool 159 available to be able to compress the initram. 160 161config INITRAMFS_COMPRESSION_LZMA 162 bool "LZMA" 163 depends on RD_LZMA 164 help 165 This algorithm's compression ratio is best but has a large dictionary 166 size which might cause issues in memory constrained systems. 167 Decompression speed is between the other choices. Compression is 168 slowest. The initramfs size is about 33% smaller with LZMA in 169 comparison to gzip. 170 171 If you choose this, keep in mind that you may need to install the xz 172 or lzma tools to be able to compress the initram. 173 174config INITRAMFS_COMPRESSION_XZ 175 bool "XZ" 176 depends on RD_XZ 177 help 178 XZ uses the LZMA2 algorithm and has a large dictionary which may cause 179 problems on memory constrained systems. The initramfs size is about 180 30% smaller with XZ in comparison to gzip. Decompression speed is 181 better than that of bzip2 but worse than gzip and LZO. Compression is 182 slow. 183 184 If you choose this, keep in mind that you may need to install the xz 185 tool to be able to compress the initram. 186 187config INITRAMFS_COMPRESSION_LZO 188 bool "LZO" 189 depends on RD_LZO 190 help 191 It's compression ratio is the second poorest amongst the choices. The 192 kernel size is about 10% bigger than gzip. Despite that, it's 193 decompression speed is the second fastest and it's compression speed 194 is quite fast too. 195 196 If you choose this, keep in mind that you may need to install the lzop 197 tool to be able to compress the initram. 198 199config INITRAMFS_COMPRESSION_LZ4 200 bool "LZ4" 201 depends on RD_LZ4 202 help 203 It's compression ratio is the poorest amongst the choices. The kernel 204 size is about 15% bigger than gzip; however its decompression speed 205 is the fastest. 206 207 If you choose this, keep in mind that most distros don't provide lz4 208 by default which could cause a build failure. 209 210endchoice 211 |
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| 102config INITRAMFS_COMPRESSION 103 string | 212config INITRAMFS_COMPRESSION 213 string |
| 214 default "" if INITRAMFS_COMPRESSION_NONE 215 default ".gz" if INITRAMFS_COMPRESSION_GZIP 216 default ".bz2" if INITRAMFS_COMPRESSION_BZIP2 217 default ".lzma" if INITRAMFS_COMPRESSION_LZMA 218 default ".xz" if INITRAMFS_COMPRESSION_XZ 219 default ".lzo" if INITRAMFS_COMPRESSION_LZO 220 default ".lz4" if INITRAMFS_COMPRESSION_LZ4 |
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| 104 default ".gz" if RD_GZIP 105 default ".lz4" if RD_LZ4 106 default ".lzo" if RD_LZO 107 default ".xz" if RD_XZ 108 default ".lzma" if RD_LZMA 109 default ".bz2" if RD_BZIP2 110 default "" | 221 default ".gz" if RD_GZIP 222 default ".lz4" if RD_LZ4 223 default ".lzo" if RD_LZO 224 default ".xz" if RD_XZ 225 default ".lzma" if RD_LZMA 226 default ".bz2" if RD_BZIP2 227 default "" |