Linux kernel. Devices and drivers

cat /proc/partitions
cat /proc/devices

tmpfs

df -h # tmpfs and subfolders v

udev

ps aux | grep [u]dev  # demons
udevadm monitor  # new devices

struct gendisk
add_disk()

struct block_device
struct block_device_operations
struct request_queue
struct request

sumit_bio()
generic_make_request

Linux I/O Scheduler
struct elevator_ops
vfs_ioctl() - call filesystem specific ioctl methods

man 2 ioctl # control device

I/O ports and I/O memmory vs DMA
IOMMU

cat /proc/ioports
cat /proc/mem

struct device
struct bus_type
bus_register()

sysfs vs Kernfs introduced in 3.14

ll /sys/block
ll /sys/bus/pci/

ISA, PCI, PCI Express

struct pci_bus

struct pci_dev
struct pci_driver

Vfs
struct inode
struct inode_operations

dmesg|grep Inode
#[    0.001283] Inode-cache hash table entries: 262144 (order: 9, 2097152 bytes)

struct file_struct - opened by process

struct file
struct file_operations

RCU

struct dentry
struct dentry_operations

NFS, AFS, SMB (CIFS)

struct super_block

mount
ll /dev/disk/by-*

ramfs, tmpfs, sysfs, procfs, debugfs CONFIG_DEBUG_FS

cat /proc/filesystems
ll /proc/buddyinfo
cat /proc/buddyinfo
cat /proc/slabinfo
sudo cat /proc/slabinfo
cat /proc/vmstat
cat /proc/kallsyms
ll /proc/kcore  # + gdb, ddd
cat /proc/interrupts

sys_open() - adds fd to current->fs
ACL
Ext2 reservation window

Ext3
writeback, ordered, journal