刚发现一个linux在线文档库。很好很强大。
http://blog.csdn.net/longxibendi/article/details/6048231
1.网址： http://www.mjmwired.net
2.比如查看这个 proc.txt ,就在这里能找到。
http://www.mjmwired.net/kernel/Documentation/filesystems/proc.txt
内核参数解释全在这里了。不过，也可以下载内核完源代码，从/usr/src/linux/Documentation/proc.txt查看
下载内核从http://www.kernel.org/pub/linux/kernel/v2.6/
解压完后从这里打开：
linux-2.6.28/Documentation/filesystems/proc.txt
3.此外，在filesystems下还有很多文档，比如ext4.txt，很详细，很全面，很有用。
4.这里提供一个2.6.28的完整proc.txt文档
注意linux系统管理技术手册 第二版 说的是 proc.txt 在 /usr/src/linux/Documentation/proc.txt ，具体问题，具体分析吧。
- ------------------------------------------------------------------------------
- T H E /proc F I L E S Y S T E M
- ------------------------------------------------------------------------------
- /proc/sys Terrehon Bowden
- Bodo Bauer
- 2.4.x update Jorge Nerin
- ------------------------------------------------------------------------------
- Version 1.3 Kernel version 2.2.12
- Kernel version 2.4.0-test11-pre4
- ------------------------------------------------------------------------------
- Table of Contents
- -----------------
- 0 Preface
- 0.1 Introduction/Credits
- 0.2 Legal Stuff
- 1 Collecting System Information
- 1.1 Process-Specific Subdirectories
- 1.2 Kernel data
- 1.3 IDE devices in /proc/ide
- 1.4 Networking info in /proc/net
- 1.5 SCSI info
- 1.6 Parallel port info in /proc/parport
- 1.7 TTY info in /proc/tty
- 1.8 Miscellaneous kernel statistics in /proc/stat
- 2 Modifying System Parameters
- 2.1 /proc/sys/fs - File system data
- 2.2 /proc/sys/fs/binfmt_misc - Miscellaneous binary formats
- 2.3 /proc/sys/kernel - general kernel parameters
- 2.4 /proc/sys/vm - The virtual memory subsystem
- 2.5 /proc/sys/dev - Device specific parameters
- 2.6 /proc/sys/sunrpc - Remote procedure calls
- 2.7 /proc/sys/net - Networking stuff
- 2.8 /proc/sys/net/ipv4 - IPV4 settings
- 2.9 Appletalk
- 2.10 IPX
- 2.11 /proc/sys/fs/mqueue - POSIX message queues filesystem
- 2.12 /proc/
/oom_adj - Adjust the oom-killer score - 2.13 /proc/
/oom_score - Display current oom-killer score - 2.14 /proc/
/io - Display the IO accounting fields - 2.15 /proc/
/coredump_filter - Core dump filtering settings - 2.16 /proc/
/mountinfo - Information about mounts - 2.17 /proc/sys/fs/epoll - Configuration options for the epoll interface
- ------------------------------------------------------------------------------
- Preface
- ------------------------------------------------------------------------------
- 0.1 Introduction/Credits
- ------------------------
- This documentation is part of a soon (or so we hope) to be released book on
- the SuSE Linux distribution. As there is no complete documentation for the
- /proc file system and we've used many freely available sources to write these
- chapters, it seems only fair to give the work back to the Linux community.
- This work is based on the 2.2.* kernel version and the upcoming 2.4.*. I'm
- afraid it's still far from complete, but we hope it will be useful. As far as
- we know, it is the first 'all-in-one' document about the /proc file system. It
- is focused on the Intel x86 hardware, so if you are looking for PPC, ARM,
- SPARC, AXP, etc., features, you probably won't find what you are looking for.
- It also only covers IPv4 networking, not IPv6 nor other protocols - sorry. But
- additions and patches are welcome and will be added to this document if you
- mail them to Bodo.
- We'd like to thank Alan Cox, Rik van Riel, and Alexey Kuznetsov and a lot of
- other people for help compiling this documentation. We'd also like to extend a
- special thank you to Andi Kleen for documentation, which we relied on heavily
- to create this document, as well as the additional information he provided.
- Thanks to everybody else who contributed source or docs to the Linux kernel
- and helped create a great piece of software... :)
- If you have any comments, corrections or additions, please don't hesitate to
- contact Bodo Bauer at [email protected]. We'll be happy to add them to this
- document.
- The latest version of this document is available online at
- http://skaro.nightcrawler.com/~bb/Docs/Proc as HTML version.
- If the above direction does not works for you, ypu could try the kernel
- mailing list at [email protected] and/or try to reach me at
- [email protected].
- 0.2 Legal Stuff
- ---------------
- We don't guarantee the correctness of this document, and if you come to us
- complaining about how you screwed up your system because of incorrect
- documentation, we won't feel responsible...
- ------------------------------------------------------------------------------
- CHAPTER 1: COLLECTING SYSTEM INFORMATION
- ------------------------------------------------------------------------------
- ------------------------------------------------------------------------------
- In This Chapter
- ------------------------------------------------------------------------------
- * Investigating the properties of the pseudo file system /proc and its
- ability to provide information on the running Linux system
- * Examining /proc's structure
- * Uncovering various information about the kernel and the processes running
- on the system
- ------------------------------------------------------------------------------
- The proc file system acts as an interface to internal data structures in the
- kernel. It can be used to obtain information about the system and to change
- certain kernel parameters at runtime (sysctl).
- First, we'll take a look at the read-only parts of /proc. In Chapter 2, we
- show you how you can use /proc/sys to change settings.
- 1.1 Process-Specific Subdirectories
- -----------------------------------
- The directory /proc contains (among other things) one subdirectory for each
- process running on the system, which is named after the process ID (PID).
- The link self points to the process reading the file system. Each process
- subdirectory has the entries listed in Table 1-1.
- Table 1-1: Process specific entries in /proc
- ..............................................................................
- File Content
- clear_refs Clears page referenced bits shown in smaps output
- cmdline Command line arguments
- cpu Current and last cpu in which it was executed (2.4)(smp)
- cwd Link to the current working directory
- environ Values of environment variables
- exe Link to the executable of this process
- fd Directory, which contains all file descriptors
- maps Memory maps to executables and library files (2.4)
- mem Memory held by this process
- root Link to the root directory of this process
- stat Process status
- statm Process memory status information
- status Process status in human readable form
- wchan If CONFIG_KALLSYMS is set, a pre-decoded wchan
- smaps Extension based on maps, the rss size for each mapped file
- ..............................................................................
- For example, to get the status information of a process, all you have to do is
- read the file /proc/PID/status:
- >cat /proc/self/status
- Name: cat
- State: R (running)
- Pid: 5452
- PPid: 743
- TracerPid: 0 (2.4)
- Uid: 501 501 501 501
- Gid: 100 100 100 100
- Groups: 100 14 16
- VmSize: 1112 kB
- VmLck: 0 kB
- VmRSS: 348 kB
- VmData: 24 kB
- VmStk: 12 kB
- VmExe: 8 kB
- VmLib: 1044 kB
- SigPnd: 0000000000000000
- SigBlk: 0000000000000000
- SigIgn: 0000000000000000
- SigCgt: 0000000000000000
- CapInh: 00000000fffffeff
- CapPrm: 0000000000000000
- CapEff: 0000000000000000
- This shows you nearly the same information you would get if you viewed it with
- the ps command. In fact, ps uses the proc file system to obtain its
- information. The statm file contains more detailed information about the
- process memory usage. Its seven fields are explained in Table 1-2. The stat
- file contains details information about the process itself. Its fields are
- explained in Table 1-3.
- Table 1-2: Contents of the statm files (as of 2.6.8-rc3)
- ..............................................................................
- Field Content
- size total program size (pages) (same as VmSize in status)
- resident size of memory portions (pages) (same as VmRSS in status)
- shared number of pages that are shared (i.e. backed by a file)
- trs number of pages that are 'code' (not including libs; broken,
- includes data segment)
- lrs number of pages of library (always 0 on 2.6)
- drs number of pages of data/stack (including libs; broken,
- includes library text)
- dt number of dirty pages (always 0 on 2.6)
- ..............................................................................
- Table 1-3: Contents of the stat files (as of 2.6.22-rc3)
- ..............................................................................
- Field Content
- pid process id
- tcomm filename of the executable
- state state (R is running, S is sleeping, D is sleeping in an
- uninterruptible wait, Z is zombie, T is traced or stopped)
- ppid process id of the parent process
- pgrp pgrp of the process
- sid session id
- tty_nr tty the process uses
- tty_pgrp pgrp of the tty
- flags task flags
- min_flt number of minor faults
- cmin_flt number of minor faults with child's
- maj_flt number of major faults
- cmaj_flt number of major faults with child's
- utime user mode jiffies
- stime kernel mode jiffies
- cutime user mode jiffies with child's
- cstime kernel mode jiffies with child's
- priority priority level
- nice nice level
- num_threads number of threads
- it_real_value (obsolete, always 0)
- start_time time the process started after system boot
- vsize virtual memory size
- rss resident set memory size
- rsslim current limit in bytes on the rss
- start_code address above which program text can run
- end_code address below which program text can run
- start_stack address of the start of the stack
- esp current value of ESP
- eip current value of EIP
- pending bitmap of pending signals (obsolete)
- blocked bitmap of blocked signals (obsolete)
- sigign bitmap of ignored signals (obsolete)
- sigcatch bitmap of catched signals (obsolete)
- wchan address where process went to sleep
- 0 (place holder)
- 0 (place holder)
- exit_signal signal to send to parent thread on exit
- task_cpu which CPU the task is scheduled on
- rt_priority realtime priority
- policy scheduling policy (man sched_setscheduler)
- blkio_ticks time spent waiting for block IO
- ..............................................................................
- 1.2 Kernel data
- ---------------
- Similar to the process entries, the kernel data files give information about
- the running kernel. The files used to obtain this information are contained in
- /proc and are listed in Table 1-4. Not all of these will be present in your
- system. It depends on the kernel configuration and the loaded modules, which
- files are there, and which are missing.
- Table 1-4: Kernel info in /proc
- ..............................................................................
- File Content
- apm Advanced power management info
- buddyinfo Kernel memory allocator information (see text) (2.5)
- bus Directory containing bus specific information
- cmdline Kernel command line
- cpuinfo Info about the CPU
- devices Available devices (block and character)
- dma Used DMS channels
- filesystems Supported filesystems
- driver Various drivers grouped here, currently rtc (2.4)
- execdomains Execdomains, related to security (2.4)
- fb Frame Buffer devices (2.4)
- fs File system parameters, currently nfs/exports (2.4)
- ide Directory containing info about the IDE subsystem
- interrupts Interrupt usage
- iomem Memory map (2.4)
- ioports I/O port usage
- irq Masks for irq to cpu affinity (2.4)(smp?)
- isapnp ISA PnP (Plug&Play) Info (2.4)
- kcore Kernel core image (can be ELF or A.OUT(deprecated in 2.4))
- kmsg Kernel messages
- ksyms Kernel symbol table
- loadavg Load average of last 1, 5 & 15 minutes
- locks Kernel locks
- meminfo Memory info
- misc Miscellaneous
- modules List of loaded modules
- mounts Mounted filesystems
- net Networking info (see text)
- partitions Table of partitions known to the system
- pci Deprecated info of PCI bus (new way -> /proc/bus/pci/,
- decoupled by lspci (2.4)
- rtc Real time clock
- scsi SCSI info (see text)
- slabinfo Slab pool info
- stat Overall statistics
- swaps Swap space utilization
- sys See chapter 2
- sysvipc Info of SysVIPC Resources (msg, sem, shm) (2.4)
- tty Info of tty drivers
- uptime System uptime
- version Kernel version
- video bttv info of video resources (2.4)
- vmallocinfo Show vmalloced areas
- ..............................................................................
- You can, for example, check which interrupts are currently in use and what
- they are used for by looking in the file /proc/interrupts:
- > cat /proc/interrupts
- CPU0
- 0: 8728810 XT-PIC timer
- 1: 895 XT-PIC keyboard
- 2: 0 XT-PIC cascade
- 3: 531695 XT-PIC aha152x
- 4: 2014133 XT-PIC serial
- 5: 44401 XT-PIC pcnet_cs
- 8: 2 XT-PIC rtc
- 11: 8 XT-PIC i82365
- 12: 182918 XT-PIC PS/2 Mouse
- 13: 1 XT-PIC fpu
- 14: 1232265 XT-PIC ide0
- 15: 7 XT-PIC ide1
- NMI: 0
- In 2.4.* a couple of lines where added to this file LOC & ERR (this time is the
- output of a SMP machine):
- > cat /proc/interrupts
- CPU0 CPU1
- 0: 1243498 1214548 IO-APIC-edge timer
- 1: 8949 8958 IO-APIC-edge keyboard
- 2: 0 0 XT-PIC cascade
- 5: 11286 10161 IO-APIC-edge soundblaster
- 8: 1 0 IO-APIC-edge rtc
- 9: 27422 27407 IO-APIC-edge 3c503
- 12: 113645 113873 IO-APIC-edge PS/2 Mouse
- 13: 0 0 XT-PIC fpu
- 14: 22491 24012 IO-APIC-edge ide0
- 15: 2183 2415 IO-APIC-edge ide1
- 17: 30564 30414 IO-APIC-level eth0
- 18: 177 164 IO-APIC-level bttv
- NMI: 2457961 2457959
- LOC: 2457882 2457881
- ERR: 2155
- NMI is incremented in this case because every timer interrupt generates a NMI
- (Non Maskable Interrupt) which is used by the NMI Watchdog to detect lockups.
- LOC is the local interrupt counter of the internal APIC of every CPU.
- ERR is incremented in the case of errors in the IO-APIC bus (the bus that
- connects the CPUs in a SMP system. This means that an error has been detected,
- the IO-APIC automatically retry the transmission, so it should not be a big
- problem, but you should read the SMP-FAQ.
- In 2.6.2* /proc/interrupts was expanded again. This time the goal was for
- /proc/interrupts to display every IRQ vector in use by the system, not
- just those considered 'most important'. The new vectors are:
- THR -- interrupt raised when a machine check threshold counter
- (typically counting ECC corrected errors of memory or cache) exceeds
- a configurable threshold. Only available on some systems.
- TRM -- a thermal event interrupt occurs when a temperature threshold
- has been exceeded for the CPU. This interrupt may also be generated
- when the temperature drops back to normal.
- SPU -- a spurious interrupt is some interrupt that was raised then lowered
- by some IO device before it could be fully processed by the APIC. Hence
- the APIC sees the interrupt but does not know what device it came from.
- For this case the APIC will generate the interrupt with a IRQ vector
- of 0xff. This might also be generated by chipset bugs.
- RES, CAL, TLB -- rescheduling, call and TLB flush interrupts are
- sent from one CPU to another per the needs of the OS. Typically,
- their statistics are used by kernel developers and interested users to
- determine the occurance of interrupt of the given type.
- The above IRQ vectors are displayed only when relevent. For example,
- the threshold vector does not exist on x86_64 platforms. Others are
- suppressed when the system is a uniprocessor. As of this writing, only
- i386 and x86_64 platforms support the new IRQ vector displays.
- Of some interest is the introduction of the /proc/irq directory to 2.4.
- It could be used to set IRQ to CPU affinity, this means that you can "hook" an
- IRQ to only one CPU, or to exclude a CPU of handling IRQs. The contents of the
- irq subdir is one subdir for each IRQ, and two files; default_smp_affinity and
- prof_cpu_mask.
- For example
- > ls /proc/irq/
- 0 10 12 14 16 18 2 4 6 8 prof_cpu_mask
- 1 11 13 15 17 19 3 5 7 9 default_smp_affinity
- > ls /proc/irq/0/
- smp_affinity
- smp_affinity is a bitmask, in which you can specify which CPUs can handle the
- IRQ, you can set it by doing:
- > echo 1 > /proc/irq/10/smp_affinity
- This means that only the first CPU will handle the IRQ, but you can also echo
- 5 which means that only the first and fourth CPU can handle the IRQ.
- The contents of each smp_affinity file is the same by default:
- > cat /proc/irq/0/smp_affinity
- ffffffff
- The default_smp_affinity mask applies to all non-active IRQs, which are the
- IRQs which have not yet been allocated/activated, and hence which lack a
- /proc/irq/[0-9]* directory.
- prof_cpu_mask specifies which CPUs are to be profiled by the system wide
- profiler. Default value is ffffffff (all cpus).
- The way IRQs are routed is handled by the IO-APIC, and it's Round Robin
- between all the CPUs which are allowed to handle it. As usual the kernel has
- more info than you and does a better job than you, so the defaults are the
- best choice for almost everyone.
- There are three more important subdirectories in /proc: net, scsi, and sys.
- The general rule is that the contents, or even the existence of these
- directories, depend on your kernel configuration. If SCSI is not enabled, the
- directory scsi may not exist. The same is true with the net, which is there
- only when networking support is present in the running kernel.
- The slabinfo file gives information about memory usage at the slab level.
- Linux uses slab pools for memory management above page level in version 2.2.
- Commonly used objects have their own slab pool (such as network buffers,
- directory cache, and so on).
- ..............................................................................
- > cat /proc/buddyinfo
- Node 0, zone DMA 0 4 5 4 4 3 ...
- Node 0, zone Normal 1 0 0 1 101 8 ...
- Node 0, zone HighMem 2 0 0 1 1 0 ...
- Memory fragmentation is a problem under some workloads, and buddyinfo is a
- useful tool for helping diagnose these problems. Buddyinfo will give you a
- clue as to how big an area you can safely allocate, or why a previous
- allocation failed.
- Each column represents the number of pages of a certain order which are
- available. In this case, there are 0 chunks of 2^0*PAGE_SIZE available in
- ZONE_DMA, 4 chunks of 2^1*PAGE_SIZE in ZONE_DMA, 101 chunks of 2^4*PAGE_SIZE
- available in ZONE_NORMAL, etc...
- ..............................................................................
- meminfo:
- Provides information about distribution and utilization of memory. This
- varies by architecture and compile options. The following is from a
- 16GB PIII, which has highmem enabled. You may not have all of these fields.
- > cat /proc/meminfo
- MemTotal: 16344972 kB
- MemFree: 13634064 kB
- Buffers: 3656 kB
- Cached: 1195708 kB
- SwapCached: 0 kB
- Active: 891636 kB
- Inactive: 1077224 kB
- HighTotal: 15597528 kB
- HighFree: 13629632 kB
- LowTotal: 747444 kB
- LowFree: 4432 kB
- SwapTotal: 0 kB
- SwapFree: 0 kB
- Dirty: 968 kB
- Writeback: 0 kB
- AnonPages: 861800 kB
- Mapped: 280372 kB
- Slab: 284364 kB
- SReclaimable: 159856 kB
- SUnreclaim: 124508 kB
- PageTables: 24448 kB
- NFS_Unstable: 0 kB
- Bounce: 0 kB
- WritebackTmp: 0 kB
- CommitLimit: 7669796 kB
- Committed_AS: 100056 kB
- VmallocTotal: 112216 kB
- VmallocUsed: 428 kB
- VmallocChunk: 111088 kB
- MemTotal: Total usable ram (i.e. physical ram minus a few reserved
- bits and the kernel binary code)
- MemFree: The sum of LowFree+HighFree
- Buffers: Relatively temporary storage for raw disk blocks
- shouldn't get tremendously large (20MB or so)
- Cached: in-memory cache for files read from the disk (the
- pagecache). Doesn't include SwapCached
- SwapCached: Memory that once was swapped out, is swapped back in but
- still also is in the swapfile (if memory is needed it
- doesn't need to be swapped out AGAIN because it is already
- in the swapfile. This saves I/O)
- Active: Memory that has been used more recently and usually not
- reclaimed unless absolutely necessary.
- Inactive: Memory which has been less recently used. It is more
- eligible to be reclaimed for other purposes
- HighTotal:
- HighFree: Highmem is all memory above ~860MB of physical memory
- Highmem areas are for use by userspace programs, or
- for the pagecache. The kernel must use tricks to access
- this memory, making it slower to access than lowmem.
- LowTotal:
- LowFree: Lowmem is memory which can be used for everything that
- highmem can be used for, but it is also available for the
- kernel's use for its own data structures. Among many
- other things, it is where everything from the Slab is
- allocated. Bad things happen when you're out of lowmem.
- SwapTotal: total amount of swap space available
- SwapFree: Memory which has been evicted from RAM, and is temporarily
- on the disk
- Dirty: Memory which is waiting to get written back to the disk
- Writeback: Memory which is actively being written back to the disk
- AnonPages: Non-file backed pages mapped into userspace page tables
- Mapped: files which have been mmaped, such as libraries
- Slab: in-kernel data structures cache
- SReclaimable: Part of Slab, that might be reclaimed, such as caches
- SUnreclaim: Part of Slab, that cannot be reclaimed on memory pressure
- PageTables: amount of memory dedicated to the lowest level of page
- tables.
- NFS_Unstable: NFS pages sent to the server, but not yet committed to stable
- storage
- Bounce: Memory used for block device "bounce buffers"
- WritebackTmp: Memory used by FUSE for temporary writeback buffers
- CommitLimit: Based on the overcommit ratio ('vm.overcommit_ratio'),
- this is the total amount of memory currently available to
- be allocated on the system. This limit is only adhered to
- if strict overcommit accounting is enabled (mode 2 in
- 'vm.overcommit_memory').
- The CommitLimit is calculated with the following formula:
- CommitLimit = ('vm.overcommit_ratio' * Physical RAM) + Swap
- For example, on a system with 1G of physical RAM and 7G
- of swap with a `vm.overcommit_ratio` of 30 it would
- yield a CommitLimit of 7.3G.
- For more details, see the memory overcommit documentation
- in vm/overcommit-accounting.
- Committed_AS: The amount of memory presently allocated on the system.
- The committed memory is a sum of all of the memory which
- has been allocated by processes, even if it has not been
- "used" by them as of yet. A process which malloc()'s 1G
- of memory, but only touches 300M of it will only show up
- as using 300M of memory even if it has the address space
- allocated for the entire 1G. This 1G is memory which has
- been "committed" to by the VM and can be used at any time
- by the allocating application. With strict overcommit
- enabled on the system (mode 2 in 'vm.overcommit_memory'),
- allocations which would exceed the CommitLimit (detailed
- above) will not be permitted. This is useful if one needs
- to guarantee that processes will not fail due to lack of
- memory once that memory has been successfully allocated.
- VmallocTotal: total size of vmalloc memory area
- VmallocUsed: amount of vmalloc area which is used
- VmallocChunk: largest contigious block of vmalloc area which is free
- ..............................................................................
- vmallocinfo:
- Provides information about vmalloced/vmaped areas. One line per area,
- containing the virtual address range of the area, size in bytes,
- caller information of the creator, and optional information depending
- on the kind of area :
- pages=nr number of pages
- phys=addr if a physical address was specified
- ioremap I/O mapping (ioremap() and friends)
- vmalloc vmalloc() area
- vmap vmap()ed pages
- user VM_USERMAP area
- vpages buffer for pages pointers was vmalloced (huge area)
- N
=nr (Only on NUMA kernels) - Number of pages allocated on memory node
- > cat /proc/vmallocinfo
- 0xffffc20000000000-0xffffc20000201000 2101248 alloc_large_system_hash+0x204 ...
- /0x2c0 pages=512 vmalloc N0=128 N1=128 N2=128 N3=128
- 0xffffc20000201000-0xffffc20000302000 1052672 alloc_large_system_hash+0x204 ...
- /0x2c0 pages=256 vmalloc N0=64 N1=64 N2=64 N3=64
- 0xffffc20000302000-0xffffc20000304000 8192 acpi_tb_verify_table+0x21/0x4f...
- phys=7fee8000 ioremap
- 0xffffc20000304000-0xffffc20000307000 12288 acpi_tb_verify_table+0x21/0x4f...
- phys=7fee7000 ioremap
- 0xffffc2000031d000-0xffffc2000031f000 8192 init_vdso_vars+0x112/0x210
- 0xffffc2000031f000-0xffffc2000032b000 49152 cramfs_uncompress_init+0x2e ...
- /0x80 pages=11 vmalloc N0=3 N1=3 N2=2 N3=3
- 0xffffc2000033a000-0xffffc2000033d000 12288 sys_swapon+0x640/0xac0 ...
- pages=2 vmalloc N1=2
- 0xffffc20000347000-0xffffc2000034c000 20480 xt_alloc_table_info+0xfe ...
- /0x130 [x_tables] pages=4 vmalloc N0=4
- 0xffffffffa0000000-0xffffffffa000f000 61440 sys_init_module+0xc27/0x1d00 ...
- pages=14 vmalloc N2=14
- 0xffffffffa000f000-0xffffffffa0014000 20480 sys_init_module+0xc27/0x1d00 ...
- pages=4 vmalloc N1=4
- 0xffffffffa0014000-0xffffffffa0017000 12288 sys_init_module+0xc27/0x1d00 ...
- pages=2 vmalloc N1=2
- 0xffffffffa0017000-0xffffffffa0022000 45056 sys_init_module+0xc27/0x1d00 ...
- pages=10 vmalloc N0=10
- 1.3 IDE devices in /proc/ide
- ----------------------------
- The subdirectory /proc/ide contains information about all IDE devices of which
- the kernel is aware. There is one subdirectory for each IDE controller, the
- file drivers and a link for each IDE device, pointing to the device directory
- in the controller specific subtree.
- The file drivers contains general information about the drivers used for the
- IDE devices:
- > cat /proc/ide/drivers
- ide-cdrom version 4.53
- ide-disk version 1.08
- More detailed information can be found in the controller specific
- subdirectories. These are named ide0, ide1 and so on. Each of these
- directories contains the files shown in table 1-5.
- Table 1-5: IDE controller info in /proc/ide/ide?
- ..............................................................................
- File Content
- channel IDE channel (0 or 1)
- config Configuration (only for PCI/IDE bridge)
- mate Mate name
- model Type/Chipset of IDE controller
- ..............................................................................
- Each device connected to a controller has a separate subdirectory in the
- controllers directory. The files listed in table 1-6 are contained in these
- directories.
- Table 1-6: IDE device information
- ..............................................................................
- File Content
- cache The cache
- capacity Capacity of the medium (in 512Byte blocks)
- driver driver and version
- geometry physical and logical geometry
- identify device identify block
- media media type
- model device identifier
- settings device setup
- smart_thresholds IDE disk management thresholds
- smart_values IDE disk management values
- ..............................................................................
- The most interesting file is settings. This file contains a nice overview of
- the drive parameters:
- # cat /proc/ide/ide0/hda/settings
- name value min max mode
- ---- ----- --- --- ----
- bios_cyl 526 0 65535 rw
- bios_head 255 0 255 rw
- bios_sect 63 0 63 rw
- breada_readahead 4 0 127 rw
- bswap 0 0 1 r
- file_readahead 72 0 2097151 rw
- io_32bit 0 0 3 rw
- keepsettings 0 0 1 rw
- max_kb_per_request 122 1 127 rw
- multcount 0 0 8 rw
- nice1 1 0 1 rw
- nowerr 0 0 1 rw
- pio_mode write-only 0 255 w
- slow 0 0 1 rw
- unmaskirq 0 0 1 rw
- using_dma 0 0 1 rw
- 1.4 Networking info in /proc/net
- --------------------------------
- The subdirectory /proc/net follows the usual pattern. Table 1-6 shows the
- additional values you get for IP version 6 if you configure the kernel to
- support this. Table 1-7 lists the files and their meaning.
- Table 1-6: IPv6 info in /proc/net
- ..............................................................................
- File Content
- udp6 UDP sockets (IPv6)
- tcp6 TCP sockets (IPv6)
- raw6 Raw device statistics (IPv6)
- igmp6 IP multicast addresses, which this host joined (IPv6)
- if_inet6 List of IPv6 interface addresses
- ipv6_route Kernel routing table for IPv6
- rt6_stats Global IPv6 routing tables statistics
- sockstat6 Socket statistics (IPv6)
- snmp6 Snmp data (IPv6)
- ..............................................................................
- Table 1-7: Network info in /proc/net
- ..............................................................................
- File Content
- arp Kernel ARP table
- dev network devices with statistics
- dev_mcast the Layer2 multicast groups a device is listening too
- (interface index, label, number of references, number of bound
- addresses).
- dev_stat network device status
- ip_fwchains Firewall chain linkage
- ip_fwnames Firewall chain names
- ip_masq Directory containing the masquerading tables
- ip_masquerade Major masquerading table
- netstat Network statistics
- raw raw device statistics
- route Kernel routing table
- rpc Directory containing rpc info
- rt_cache Routing cache
- snmp SNMP data
- sockstat Socket statistics
- tcp TCP sockets
- tr_rif Token ring RIF routing table
- udp UDP sockets
- unix UNIX domain sockets
- wireless Wireless interface data (Wavelan etc)
- igmp IP multicast addresses, which this host joined
- psched Global packet scheduler parameters.
- netlink List of PF_NETLINK sockets
- ip_mr_vifs List of multicast virtual interfaces
- ip_mr_cache List of multicast routing cache
- ..............................................................................
- You can use this information to see which network devices are available in
- your system and how much traffic was routed over those devices:
- > cat /proc/net/dev
- Inter-|Receive |[...
- face |bytes packets errs drop fifo frame compressed multicast|[...
- lo: 908188 5596 0 0 0 0 0 0 [...
- ppp0:15475140 20721 410 0 0 410 0 0 [...
- eth0: 614530 7085 0 0 0 0 0 1 [...
- ...] Transmit
- ...] bytes packets errs drop fifo colls carrier compressed
- ...] 908188 5596 0 0 0 0 0 0
- ...] 1375103 17405 0 0 0 0 0 0
- ...] 1703981 5535 0 0 0 3 0 0
- In addition, each Channel Bond interface has it's own directory. For
- example, the bond0 device will have a directory called /proc/net/bond0/.
- It will contain information that is specific to that bond, such as the
- current slaves of the bond, the link status of the slaves, and how
- many times the slaves link has failed.
- 1.5 SCSI info
- -------------
- If you have a SCSI host adapter in your system, you'll find a subdirectory
- named after the driver for this adapter in /proc/scsi. You'll also see a list
- of all recognized SCSI devices in /proc/scsi:
- >cat /proc/scsi/scsi
- Attached devices:
- Host: scsi0 Channel: 00 Id: 00 Lun: 00
- Vendor: IBM Model: DGHS09U Rev: 03E0
- Type: Direct-Access ANSI SCSI revision: 03
- Host: scsi0 Channel: 00 Id: 06 Lun: 00
- Vendor: PIONEER Model: CD-ROM DR-U06S Rev: 1.04
- Type: CD-ROM ANSI SCSI revision: 02
- The directory named after the driver has one file for each adapter found in
- the system. These files contain information about the controller, including
- the used IRQ and the IO address range. The amount of information shown is
- dependent on the adapter you use. The example shows the output for an Adaptec
- AHA-2940 SCSI adapter:
- > cat /proc/scsi/aic7xxx/0
- Adaptec AIC7xxx driver version: 5.1.19/3.2.4
- Compile Options:
- TCQ Enabled By Default : Disabled
- AIC7XXX_PROC_STATS : Disabled
- AIC7XXX_RESET_DELAY : 5
- Adapter Configuration:
- SCSI Adapter: Adaptec AHA-294X Ultra SCSI host adapter
- Ultra Wide Controller
- PCI MMAPed I/O Base: 0xeb001000
- Adapter SEEPROM Config: SEEPROM found and used.
- Adaptec SCSI BIOS: Enabled
- IRQ: 10
- SCBs: Active 0, Max Active 2,
- Allocated 15, HW 16, Page 255
- Interrupts: 160328
- BIOS Control Word: 0x18b6
- Adapter Control Word: 0x005b
- Extended Translation: Enabled
- Disconnect Enable Flags: 0xffff
- Ultra Enable Flags: 0x0001
- Tag Queue Enable Flags: 0x0000
- Ordered Queue Tag Flags: 0x0000
- Default Tag Queue Depth: 8
- Tagged Queue By Device array for aic7xxx host instance 0:
- {255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255}
- Actual queue depth per device for aic7xxx host instance 0:
- {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1}
- Statistics:
- (scsi0:0:0:0)
- Device using Wide/Sync transfers at 40.0 MByte/sec, offset 8
- Transinfo settings: current(12/8/1/0), goal(12/8/1/0), user(12/15/1/0)
- Total transfers 160151 (74577 reads and 85574 writes)
- (scsi0:0:6:0)
- Device using Narrow/Sync transfers at 5.0 MByte/sec, offset 15
- Transinfo settings: current(50/15/0/0), goal(50/15/0/0), user(50/15/0/0)
- Total transfers 0 (0 reads and 0 writes)
- 1.6 Parallel port info in /proc/parport
- ---------------------------------------
- The directory /proc/parport contains information about the parallel ports of
- your system. It has one subdirectory for each port, named after the port
- number (0,1,2,...).
- These directories contain the four files shown in Table 1-8.
- Table 1-8: Files in /proc/parport
- ..............................................................................
- File Content
- autoprobe Any IEEE-1284 device ID information that has been acquired.
- devices list of the device drivers using that port. A + will appear by the
- name of the device currently using the port (it might not appear
- against any).
- hardware Parallel port's base address, IRQ line and DMA channel.
- irq IRQ that parport is using for that port. This is in a separate
- file to allow you to alter it by writing a new value in (IRQ
- number or none).
- ..............................................................................
- 1.7 TTY info in /proc/tty
- -------------------------
- Information about the available and actually used tty's can be found in the
- directory /proc/tty.You'll find entries for drivers and line disciplines in
- this directory, as shown in Table 1-9.
- Table 1-9: Files in /proc/tty
- ..............................................................................
- File Content
- drivers list of drivers and their usage
- ldiscs registered line disciplines
- driver/serial usage statistic and status of single tty lines
- ..............................................................................
- To see which tty's are currently in use, you can simply look into the file
- /proc/tty/drivers:
- > cat /proc/tty/drivers
- pty_slave /dev/pts 136 0-255 pty:slave
- pty_master /dev/ptm 128 0-255 pty:master
- pty_slave /dev/ttyp 3 0-255 pty:slave
- pty_master /dev/pty 2 0-255 pty:master
- serial /dev/cua 5 64-67 serial:callout
- serial /dev/ttyS 4 64-67 serial
- /dev/tty0 /dev/tty0 4 0 system:vtmaster
- /dev/ptmx /dev/ptmx 5 2 system
- /dev/console /dev/console 5 1 system:console
- /dev/tty /dev/tty 5 0 system:/dev/tty
- unknown /dev/tty 4 1-63 console
- 1.8 Miscellaneous kernel statistics in /proc/stat
- -------------------------------------------------
- Various pieces of information about kernel activity are available in the
- /proc/stat file. All of the numbers reported in this file are aggregates
- since the system first booted. For a quick look, simply cat the file:
- > cat /proc/stat
- cpu 2255 34 2290 22625563 6290 127 456 0
- cpu0 1132 34 1441 11311718 3675 127 438 0
- cpu1 1123 0 849 11313845 2614 0 18 0
- intr 114930548 113199788 3 0 5 263 0 4 [... lots more numbers ...]
- ctxt 1990473
- btime 1062191376
- processes 2915
- procs_running 1
- procs_blocked 0
- The very first "cpu" line aggregates the numbers in all of the other "cpuN"
- lines. These numbers identify the amount of time the CPU has spent performing
- different kinds of work. Time units are in USER_HZ (typically hundredths of a
- second). The meanings of the columns are as follows, from left to right:
- - user: normal processes executing in user mode
- - nice: niced processes executing in user mode
- - system: processes executing in kernel mode
- - idle: twiddling thumbs
- - iowait: waiting for I/O to complete
- - irq: servicing interrupts
- - softirq: servicing softirqs
- - steal: involuntary wait
- The "intr" line gives counts of interrupts serviced since boot time, for each
- of the possible system interrupts. The first column is the total of all
- interrupts serviced; each subsequent column is the total for that particular
- interrupt.
- The "ctxt" line gives the total number of context switches across all CPUs.
- The "btime" line gives the time at which the system booted, in seconds since
- the Unix epoch.
- The "processes" line gives the number of processes and threads created, which
- includes (but is not limited to) those created by calls to the fork() and
- clone() system calls.
- The "procs_running" line gives the number of processes currently running on
- CPUs.
- The "procs_blocked" line gives the number of processes currently blocked,
- waiting for I/O to complete.
- 1.9 Ext4 file system parameters
- ------------------------------
- Information about mounted ext4 file systems can be found in
- /proc/fs/ext4. Each mounted filesystem will have a directory in
- /proc/fs/ext4 based on its device name (i.e., /proc/fs/ext4/hdc or
- /proc/fs/ext4/dm-0). The files in each per-device directory are shown
- in Table 1-10, below.
- Table 1-10: Files in /proc/fs/ext4/
- ..............................................................................
- File Content
- mb_groups details of multiblock allocator buddy cache of free blocks
- mb_history multiblock allocation history
- stats controls whether the multiblock allocator should start
- collecting statistics, which are shown during the unmount
- group_prealloc the multiblock allocator will round up allocation
- requests to a multiple of this tuning parameter if the
- stripe size is not set in the ext4 superblock
- max_to_scan The maximum number of extents the multiblock allocator
- will search to find the best extent
- min_to_scan The minimum number of extents the multiblock allocator
- will search to find the best extent
- order2_req Tuning parameter which controls the minimum size for
- requests (as a power of 2) where the buddy cache is
- used
- stream_req Files which have fewer blocks than this tunable
- parameter will have their blocks allocated out of a
- block group specific preallocation pool, so that small
- files are packed closely together. Each large file
- will have its blocks allocated out of its own unique
- preallocation pool.
- inode_readahead Tuning parameter which controls the maximum number of
- inode table blocks that ext4's inode table readahead
- algorithm will pre-read into the buffer cache
- ..............................................................................
- ------------------------------------------------------------------------------
- Summary
- ------------------------------------------------------------------------------
- The /proc file system serves information about the running system. It not only
- allows access to process data but also allows you to request the kernel status
- by reading files in the hierarchy.
- The directory structure of /proc reflects the types of information and makes
- it easy, if not obvious, where to look for specific data.
- ------------------------------------------------------------------------------
- ------------------------------------------------------------------------------
- CHAPTER 2: MODIFYING SYSTEM PARAMETERS
- ------------------------------------------------------------------------------
- ------------------------------------------------------------------------------
- In This Chapter
- ------------------------------------------------------------------------------
- * Modifying kernel parameters by writing into files found in /proc/sys
- * Exploring the files which modify certain parameters
- * Review of the /proc/sys file tree
- ------------------------------------------------------------------------------
- A very interesting part of /proc is the directory /proc/sys. This is not only
- a source of information, it also allows you to change parameters within the
- kernel. Be very careful when attempting this. You can optimize your system,
- but you can also cause it to crash. Never alter kernel parameters on a
- production system. Set up a development machine and test to make sure that
- everything works the way you want it to. You may have no alternative but to
- reboot the machine once an error has been made.
- To change a value, simply echo the new value into the file. An example is
- given below in the section on the file system data. You need to be root to do
- this. You can create your own boot script to perform this every time your
- system boots.
- The files in /proc/sys can be used to fine tune and monitor miscellaneous and
- general things in the operation of the Linux kernel. Since some of the files
- can inadvertently disrupt your system, it is advisable to read both
- documentation and source before actually making adjustments. In any case, be
- very careful when writing to any of these files. The entries in /proc may
- change slightly between the 2.1.* and the 2.2 kernel, so if there is any doubt
- review the kernel documentation in the directory /usr/src/linux/Documentation.
- This chapter is heavily based on the documentation included in the pre 2.2
- kernels, and became part of it in version 2.2.1 of the Linux kernel.
- 2.1 /proc/sys/fs - File system data
- -----------------------------------
- This subdirectory contains specific file system, file handle, inode, dentry
- and quota information.
- Currently, these files are in /proc/sys/fs:
- dentry-state
- ------------
- Status of the directory cache. Since directory entries are dynamically
- allocated and deallocated, this file indicates the current status. It holds
- six values, in which the last two are not used and are always zero. The others
- are listed in table 2-1.
- Table 2-1: Status files of the directory cache
- ..............................................................................
- File Content
- nr_dentry Almost always zero
- nr_unused Number of unused cache entries
- age_limit
- in seconds after the entry may be reclaimed, when memory is short
- want_pages internally
- ..............................................................................
- dquot-nr and dquot-max
- ----------------------
- The file dquot-max shows the maximum number of cached disk quota entries.
- The file dquot-nr shows the number of allocated disk quota entries and the
- number of free disk quota entries.
- If the number of available cached disk quotas is very low and you have a large
- number of simultaneous system users, you might want to raise the limit.
- file-nr and file-max
- --------------------
- The kernel allocates file handles dynamically, but doesn't free them again at
- this time.
- The value in file-max denotes the maximum number of file handles that the
- Linux kernel will allocate. When you get a lot of error messages about running
- out of file handles, you might want to raise this limit. The default value is
- 10% of RAM in kilobytes. To change it, just write the new number into the
- file:
- # cat /proc/sys/fs/file-max
- 4096
- # echo 8192 > /proc/sys/fs/file-max
- # cat /proc/sys/fs/file-max
- 8192
- This method of revision is useful for all customizable parameters of the
- kernel - simply echo the new value to the corresponding file.
- Historically, the three values in file-nr denoted the number of allocated file
- handles, the number of allocated but unused file handles, and the maximum
- number of file handles. Linux 2.6 always reports 0 as the number of free file
- handles -- this is not an error, it just means that the number of allocated
- file handles exactly matches the number of used file handles.
- Attempts to allocate more file descriptors than file-max are reported with
- printk, look for "VFS: file-max limit
reached" . - inode-state and inode-nr
- ------------------------
- The file inode-nr contains the first two items from inode-state, so we'll skip
- to that file...
- inode-state contains two actual numbers and five dummy values. The numbers
- are nr_inodes and nr_free_inodes (in order of appearance).
- nr_inodes
- ~~~~~~~~~
- Denotes the number of inodes the system has allocated. This number will
- grow and shrink dynamically.
- nr_open
- -------
- Denotes the maximum number of file-handles a process can
- allocate. Default value is 1024*1024 (1048576) which should be
- enough for most machines. Actual limit depends on RLIMIT_NOFILE
- resource limit.
- nr_free_inodes
- --------------
- Represents the number of free inodes. Ie. The number of inuse inodes is
- (nr_inodes - nr_free_inodes).
- aio-nr and aio-max-nr
- ---------------------
- aio-nr is the running total of the number of events specified on the
- io_setup system call for all currently active aio contexts. If aio-nr
- reaches aio-max-nr then io_setup will fail with EAGAIN. Note that
- raising aio-max-nr does not result in the pre-allocation or re-sizing
- of any kernel data structures.
- 2.2 /proc/sys/fs/binfmt_misc - Miscellaneous binary formats
- -----------------------------------------------------------
- Besides these files, there is the subdirectory /proc/sys/fs/binfmt_misc. This
- handles the kernel support for miscellaneous binary formats.
- Binfmt_misc provides the ability to register additional binary formats to the
- Kernel without compiling an additional module/kernel. Therefore, binfmt_misc
- needs to know magic numbers at the beginning or the filename extension of the
- binary.
- It works by maintaining a linked list of structs that contain a description of
- a binary format, including a magic with size (or the filename extension),
- offset and mask, and the interpreter name. On request it invokes the given
- interpreter with the original program as argument, as binfmt_java and
- binfmt_em86 and binfmt_mz do. Since binfmt_misc does not define any default
- binary-formats, you have to register an additional binary-format.
- There are two general files in binfmt_misc and one file per registered format.
- The two general files are register and status.
- Registering a new binary format
- -------------------------------
- To register a new binary format you have to issue the command
- echo :name:type:offset:magic:mask:interpreter: > /proc/sys/fs/binfmt_misc/register
- with appropriate name (the name for the /proc-dir entry), offset (defaults to
- 0, if omitted), magic, mask (which can be omitted, defaults to all 0xff) and
- last but not least, the interpreter that is to be invoked (for example and
- testing /bin/echo). Type can be M for usual magic matching or E for filename
- extension matching (give extension in place of magic).
- Check or reset the status of the binary format handler
- ------------------------------------------------------
- If you do a cat on the file /proc/sys/fs/binfmt_misc/status, you will get the
- current status (enabled/disabled) of binfmt_misc. Change the status by echoing
- 0 (disables) or 1 (enables) or -1 (caution: this clears all previously
- registered binary formats) to status. For example echo 0 > status to disable
- binfmt_misc (temporarily).
- Status of a single handler
- --------------------------
- Each registered handler has an entry in /proc/sys/fs/binfmt_misc. These files
- perform the same function as status, but their scope is limited to the actual
- binary format. By cating this file, you also receive all related information
- about the interpreter/magic of the binfmt.
- Example usage of binfmt_misc (emulate binfmt_java)
- --------------------------------------------------
- cd /proc/sys/fs/binfmt_misc
- echo ':Java:M::/xca/xfe/xba/xbe::/usr/local/java/bin/javawrapper:' > register
- echo ':HTML:E::html::/usr/local/java/bin/appletviewer:' > register
- echo ':Applet:M::