linux-kernel

问题 I saw from the documentation of userfaultfd https://manpages.debian.org/testing/manpages-dev/userfaultfd.2.en.html http://man7.org/linux/man-pages/man2/ioctl_userfaultfd.2.html that userfaultfd will start supporting shared map since kernel 4.11. However, the documentation still looks very ambiguous in the sense that I'm still wondering will these include supporting file-backed mmap (which can also be MAP_SHARED)? 回答1: To answer definitively, since the information is not in the manual page(s),

问题 I saw from the documentation of userfaultfd https://manpages.debian.org/testing/manpages-dev/userfaultfd.2.en.html http://man7.org/linux/man-pages/man2/ioctl_userfaultfd.2.html that userfaultfd will start supporting shared map since kernel 4.11. However, the documentation still looks very ambiguous in the sense that I'm still wondering will these include supporting file-backed mmap (which can also be MAP_SHARED)? 回答1: To answer definitively, since the information is not in the manual page(s),

问题 I saw from the documentation of userfaultfd https://manpages.debian.org/testing/manpages-dev/userfaultfd.2.en.html http://man7.org/linux/man-pages/man2/ioctl_userfaultfd.2.html that userfaultfd will start supporting shared map since kernel 4.11. However, the documentation still looks very ambiguous in the sense that I'm still wondering will these include supporting file-backed mmap (which can also be MAP_SHARED)? 回答1: To answer definitively, since the information is not in the manual page(s),

问题 This is a part of text file from System.map and /proc/kallsyms . ffffffff8106c260 T leave_mm ffffffff8106c340 t do_flush_tlb_all ffffffff8106c390 t flush_tlb_func ffffffff8106c510 T native_flush_tlb_others ffffffff8106c540 T flush_tlb_current_task ffffffff8106c600 T flush_tlb_mm_range ffffffff8106c770 T flush_tlb_page ffffffff8106c820 T flush_tlb_all ffffffff8106c840 T flush_tlb_kernel_range What is the difference between T and t ? I know that T or t is for text (code) section. I guessed T

问题 This is a part of text file from System.map and /proc/kallsyms . ffffffff8106c260 T leave_mm ffffffff8106c340 t do_flush_tlb_all ffffffff8106c390 t flush_tlb_func ffffffff8106c510 T native_flush_tlb_others ffffffff8106c540 T flush_tlb_current_task ffffffff8106c600 T flush_tlb_mm_range ffffffff8106c770 T flush_tlb_page ffffffff8106c820 T flush_tlb_all ffffffff8106c840 T flush_tlb_kernel_range What is the difference between T and t ? I know that T or t is for text (code) section. I guessed T

问题 I'm running this command nl-qdisc-add --dev=veth-host --parent=root plug --limit=32768 It throws an error of Error: Unable to load module "/usr/lib/x86_64-linux-gnu/libnl/cli/qdisc/plug.so": /usr/lib/x86_64-linux-gnu/libnl/cli/qdisc/plug.so: cannot open shared object file: No such file or directory I looked into the folder and found that there was another folder present named libnl-3 with same files. I can't even rename it to run the command. How can i resolve this? Even if i successfully

问题 I'm running this command nl-qdisc-add --dev=veth-host --parent=root plug --limit=32768 It throws an error of Error: Unable to load module "/usr/lib/x86_64-linux-gnu/libnl/cli/qdisc/plug.so": /usr/lib/x86_64-linux-gnu/libnl/cli/qdisc/plug.so: cannot open shared object file: No such file or directory I looked into the folder and found that there was another folder present named libnl-3 with same files. I can't even rename it to run the command. How can i resolve this? Even if i successfully

问题 Assume we have a file of FILE_SIZE bytes, and: FILE_SIZE <= min(page_size, physical_block_size) ; file size never changes (i.e. truncate() or append write() are never performed); file is modified only by completly overwriting its contents using: pwrite(fd, buf, FILE_SIZE, 0); Is it guaranteed on ext4 that: Such writes are atomic with respect to concurrent reads? Such writes are transactional with respect to a system crash? (i.e., after a crash the file's contents is completely from some

问题 Assume we have a file of FILE_SIZE bytes, and: FILE_SIZE <= min(page_size, physical_block_size) ; file size never changes (i.e. truncate() or append write() are never performed); file is modified only by completly overwriting its contents using: pwrite(fd, buf, FILE_SIZE, 0); Is it guaranteed on ext4 that: Such writes are atomic with respect to concurrent reads? Such writes are transactional with respect to a system crash? (i.e., after a crash the file's contents is completely from some

问题 Assume we have a file of FILE_SIZE bytes, and: FILE_SIZE <= min(page_size, physical_block_size) ; file size never changes (i.e. truncate() or append write() are never performed); file is modified only by completly overwriting its contents using: pwrite(fd, buf, FILE_SIZE, 0); Is it guaranteed on ext4 that: Such writes are atomic with respect to concurrent reads? Such writes are transactional with respect to a system crash? (i.e., after a crash the file's contents is completely from some