Bitfields have their uses, but the uses here didn't make any sense. Code generated to read or write bitfields is more complicated (and slower) because, well, the bits need to be manipulated with special instructions. So bitfields should be used when we have a structure that is repeated hundreds or thousands of times in memory and those saving are higher than the cost of having more complicated code. This can happen for example in the kernel code. But the code here has structures that are instantiated once or or at most few times. In addition, a bitfield often does not save any memory because of alignment requirements. In the majority of cases modified here, the bitfield was the last field in a structure, so no memory savings were made. $ size build*/{mkswap,more,ul,col,rtcwake,lsmem,lscpu,eject,dmesg,uuidd,taskset,login} text data bss dec hex filename 132014 1988 88 134090 20bca build/mkswap 129342 1852 88 131282 200d2 build2/mkswap 55161 1480 128 56769 ddc1 build/more 54265 1480 128 55873 da41 build2/more 14364 868 112 15344 3bf0 build/ul 14316 868 112 15296 3bc0 build2/ul 28547 1000 112 29659 73db build/col 28435 1000 112 29547 736b build2/col 46914 1960 112 48986 bf5a build/rtcwake 46834 1960 112 48906 bf0a build2/rtcwake 63419 1744 176 65339 ff3b build/lsmem 63403 1744 176 65323 ff2b build2/lsmem 159885 2864 464 163213 27d8d build/lscpu 159757 2864 464 163085 27d0d build2/lscpu 90041 1704 88 91833 166b9 build/eject 89737 1704 88 91529 16589 build2/eject 82150 5152 1032 88334 1590e build/dmesg 81846 5152 1032 88030 157de build2/dmesg 37601 1368 80 39049 9889 build/uuidd 37585 1368 80 39033 9879 build2/uuidd 58906 1336 56 60298 eb8a build/taskset 58890 1336 56 60282 eb7a build2/taskset 84761 2128 152 87041 15401 build/login 84672 2128 152 86952 153a8 build2/login (To be clear: those small savings are not particularly important. The motivation for this patch is to eradicate the antipattern of making things more complicated without any benefit.)