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Diffstat (limited to 'Documentation/filesystems/proc.rst')
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1 files changed, 91 insertions, 38 deletions
diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst index 1bc91fb8c321..c6a6b9df2104 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -47,6 +47,7 @@ fixes/update part 1.1 Stefani Seibold <stefani@seibold.net> June 9 2009 3.10 /proc/<pid>/timerslack_ns - Task timerslack value 3.11 /proc/<pid>/patch_state - Livepatch patch operation state 3.12 /proc/<pid>/arch_status - Task architecture specific information + 3.13 /proc/<pid>/fd - List of symlinks to open files 4 Configuring procfs 4.1 Mount options @@ -84,7 +85,7 @@ contact Bodo Bauer at bb@ricochet.net. We'll be happy to add them to this document. The latest version of this document is available online at -http://tldp.org/LDP/Linux-Filesystem-Hierarchy/html/proc.html +https://www.kernel.org/doc/html/latest/filesystems/proc.html If the above direction does not works for you, you could try the kernel mailing list at linux-kernel@vger.kernel.org and/or try to reach me at @@ -178,6 +179,7 @@ read the file /proc/PID/status:: Gid: 100 100 100 100 FDSize: 256 Groups: 100 14 16 + Kthread: 0 VmPeak: 5004 kB VmSize: 5004 kB VmLck: 0 kB @@ -231,7 +233,7 @@ asynchronous manner and the value may not be very precise. To see a precise snapshot of a moment, you can see /proc/<pid>/smaps file and scan page table. It's slow but very precise. -.. table:: Table 1-2: Contents of the status files (as of 4.19) +.. table:: Table 1-2: Contents of the status fields (as of 4.19) ========================== =================================================== Field Content @@ -245,7 +247,8 @@ It's slow but very precise. Ngid NUMA group ID (0 if none) Pid process id PPid process id of the parent process - TracerPid PID of process tracing this process (0 if not) + TracerPid PID of process tracing this process (0 if not, or + the tracer is outside of the current pid namespace) Uid Real, effective, saved set, and file system UIDs Gid Real, effective, saved set, and file system GIDs FDSize number of file descriptor slots currently allocated @@ -254,6 +257,7 @@ It's slow but very precise. NSpid descendant namespace process ID hierarchy NSpgid descendant namespace process group ID hierarchy NSsid descendant namespace session ID hierarchy + Kthread kernel thread flag, 1 is yes, 0 is no VmPeak peak virtual memory size VmSize total program size VmLck locked memory size @@ -303,7 +307,7 @@ It's slow but very precise. ========================== =================================================== -.. table:: Table 1-3: Contents of the statm files (as of 2.6.8-rc3) +.. table:: Table 1-3: Contents of the statm fields (as of 2.6.8-rc3) ======== =============================== ============================== Field Content @@ -321,7 +325,7 @@ It's slow but very precise. ======== =============================== ============================== -.. table:: Table 1-4: Contents of the stat files (as of 2.6.30-rc7) +.. table:: Table 1-4: Contents of the stat fields (as of 2.6.30-rc7) ============= =============================================================== Field Content @@ -426,14 +430,16 @@ with the memory region, as the case would be with BSS (uninitialized data). The "pathname" shows the name associated file for this mapping. If the mapping is not associated with a file: - ============= ==================================== + =================== =========================================== [heap] the heap of the program [stack] the stack of the main process [vdso] the "virtual dynamic shared object", the kernel system call handler - [anon:<name>] an anonymous mapping that has been + [anon:<name>] a private anonymous mapping that has been named by userspace - ============= ==================================== + [anon_shmem:<name>] an anonymous shared memory mapping that has + been named by userspace + =================== =========================================== or if empty, the mapping is anonymous. @@ -448,12 +454,14 @@ Memory Area, or VMA) there is a series of lines such as the following:: MMUPageSize: 4 kB Rss: 892 kB Pss: 374 kB + Pss_Dirty: 0 kB Shared_Clean: 892 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 892 kB Anonymous: 0 kB + KSM: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB @@ -479,7 +487,9 @@ dirty shared and private pages in the mapping. The "proportional set size" (PSS) of a process is the count of pages it has in memory, where each page is divided by the number of processes sharing it. So if a process has 1000 pages all to itself, and 1000 shared with one other -process, its PSS will be 1500. +process, its PSS will be 1500. "Pss_Dirty" is the portion of PSS which +consists of dirty pages. ("Pss_Clean" is not included, but it can be +calculated by subtracting "Pss_Dirty" from "Pss".) Note that even a page which is part of a MAP_SHARED mapping, but has only a single pte mapped, i.e. is currently used by only one process, is accounted @@ -492,18 +502,21 @@ accessed. a mapping associated with a file may contain anonymous pages: when MAP_PRIVATE and a page is modified, the file page is replaced by a private anonymous copy. +"KSM" reports how many of the pages are KSM pages. Note that KSM-placed zeropages +are not included, only actual KSM pages. + "LazyFree" shows the amount of memory which is marked by madvise(MADV_FREE). The memory isn't freed immediately with madvise(). It's freed in memory pressure if the memory is clean. Please note that the printed value might be lower than the real value due to optimizations used in the current implementation. If this is not desirable please file a bug report. -"AnonHugePages" shows the ammount of memory backed by transparent hugepage. +"AnonHugePages" shows the amount of memory backed by transparent hugepage. -"ShmemPmdMapped" shows the ammount of shared (shmem/tmpfs) memory backed by +"ShmemPmdMapped" shows the amount of shared (shmem/tmpfs) memory backed by huge pages. -"Shared_Hugetlb" and "Private_Hugetlb" show the ammounts of memory backed by +"Shared_Hugetlb" and "Private_Hugetlb" show the amounts of memory backed by hugetlbfs page which is *not* counted in "RSS" or "PSS" field for historical reasons. And these are not included in {Shared,Private}_{Clean,Dirty} field. @@ -514,8 +527,10 @@ replaced by copy-on-write) part of the underlying shmem object out on swap. "SwapPss" shows proportional swap share of this mapping. Unlike "Swap", this does not take into account swapped out page of underlying shmem objects. "Locked" indicates whether the mapping is locked in memory or not. -"THPeligible" indicates whether the mapping is eligible for allocating THP -pages - 1 if true, 0 otherwise. It just shows the current status. + +"THPeligible" indicates whether the mapping is eligible for allocating +naturally aligned THP pages of any currently enabled size. 1 if true, 0 +otherwise. "VmFlags" field deserves a separate description. This member represents the kernel flags associated with the particular virtual memory area in two letter @@ -550,11 +565,12 @@ encoded manner. The codes are the following: mm mixed map area hg huge page advise flag nh no huge page advise flag - mg mergable advise flag + mg mergeable advise flag bt arm64 BTI guarded page mt arm64 MTE allocation tags are enabled um userfaultfd missing tracking uw userfaultfd wr-protect tracking + ss shadow stack page == ======================================= Note that there is no guarantee that every flag and associated mnemonic will @@ -673,9 +689,15 @@ files are there, and which are missing. File Content ============ =============================================================== apm Advanced power management info + bootconfig Kernel command line obtained from boot config, + and, if there were kernel parameters from the + boot loader, a "# Parameters from bootloader:" + line followed by a line containing those + parameters prefixed by "# ". (5.5) buddyinfo Kernel memory allocator information (see text) (2.5) bus Directory containing bus specific information - cmdline Kernel command line + cmdline Kernel command line, both from bootloader and embedded + in the kernel image cpuinfo Info about the CPU devices Available devices (block and character) dma Used DMS channels @@ -977,6 +999,7 @@ Example output. You may not have all of these fields. SUnreclaim: 142336 kB KernelStack: 11168 kB PageTables: 20540 kB + SecPageTables: 0 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB @@ -986,6 +1009,7 @@ Example output. You may not have all of these fields. VmallocUsed: 40444 kB VmallocChunk: 0 kB Percpu: 29312 kB + EarlyMemtestBad: 0 kB HardwareCorrupted: 0 kB AnonHugePages: 4149248 kB ShmemHugePages: 0 kB @@ -1068,7 +1092,7 @@ Writeback AnonPages Non-file backed pages mapped into userspace page tables Mapped - files which have been mmaped, such as libraries + files which have been mmapped, such as libraries Shmem Total memory used by shared memory (shmem) and tmpfs KReclaimable @@ -1085,6 +1109,9 @@ KernelStack Memory consumed by the kernel stacks of all tasks PageTables Memory consumed by userspace page tables +SecPageTables + Memory consumed by secondary page tables, this currently + currently includes KVM mmu allocations on x86 and arm64. NFS_Unstable Always zero. Previous counted pages which had been written to the server, but has not been committed to stable storage. @@ -1109,7 +1136,7 @@ CommitLimit yield a CommitLimit of 7.3G. For more details, see the memory overcommit documentation - in vm/overcommit-accounting. + in mm/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 @@ -1133,6 +1160,13 @@ VmallocChunk Percpu Memory allocated to the percpu allocator used to back percpu allocations. This stat excludes the cost of metadata. +EarlyMemtestBad + The amount of RAM/memory in kB, that was identified as corrupted + by early memtest. If memtest was not run, this field will not + be displayed at all. Size is never rounded down to 0 kB. + That means if 0 kB is reported, you can safely assume + there was at least one pass of memtest and none of the passes + found a single faulty byte of RAM. HardwareCorrupted The amount of RAM/memory in KB, the kernel identifies as corrupted. @@ -1271,6 +1305,7 @@ support this. Table 1-9 lists the files and their meaning. rt_cache Routing cache snmp SNMP data sockstat Socket statistics + softnet_stat Per-CPU incoming packets queues statistics of online CPUs tcp TCP sockets udp UDP sockets unix UNIX domain sockets @@ -1307,9 +1342,9 @@ many times the slaves link has failed. 1.4 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:: +If you have a SCSI or ATA 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: @@ -1435,16 +1470,18 @@ Various pieces of information about kernel activity are available in the 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 0 0 - cpu0 1132 34 1441 11311718 3675 127 438 0 0 0 - cpu1 1123 0 849 11313845 2614 0 18 0 0 0 - intr 114930548 113199788 3 0 5 263 0 4 [... lots more numbers ...] - ctxt 1990473 - btime 1062191376 - processes 2915 - procs_running 1 + cpu 237902850 368826709 106375398 1873517540 1135548 0 14507935 0 0 0 + cpu0 60045249 91891769 26331539 468411416 495718 0 5739640 0 0 0 + cpu1 59746288 91759249 26609887 468860630 312281 0 4384817 0 0 0 + cpu2 59489247 92985423 26904446 467808813 171668 0 2268998 0 0 0 + cpu3 58622065 92190267 26529524 468436680 155879 0 2114478 0 0 0 + intr 8688370575 8 3373 0 0 0 0 0 0 1 40791 0 0 353317 0 0 0 0 224789828 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 190974333 41958554 123983334 43 0 224593 0 0 0 <more 0's deleted> + ctxt 22848221062 + btime 1605316999 + processes 746787147 + procs_running 2 procs_blocked 0 - softirq 183433 0 21755 12 39 1137 231 21459 2263 + softirq 12121874454 100099120 3938138295 127375644 2795979 187870761 0 173808342 3072582055 52608 224184354 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 @@ -1506,8 +1543,8 @@ softirq. 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 1-12, below. +/proc/fs/ext4/sda9 or /proc/fs/ext4/dm-0). The files in each per-device +directory are shown in Table 1-12, below. .. table:: Table 1-12: Files in /proc/fs/ext4/<devname> @@ -1587,12 +1624,12 @@ 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. +review the kernel documentation in the directory 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. -Please see: Documentation/admin-guide/sysctl/ directory for descriptions of these -entries. +Please see: Documentation/admin-guide/sysctl/ directory for descriptions of +these entries. Summary ------- @@ -1862,8 +1899,8 @@ For more information on mount propagation see: These files provide a method to access a task's comm value. It also allows for a task to set its own or one of its thread siblings comm value. The comm value is limited in size compared to the cmdline value, so writing anything longer -then the kernel's TASK_COMM_LEN (currently 16 chars) will result in a truncated -comm value. +then the kernel's TASK_COMM_LEN (currently 16 chars, including the NUL +terminator) will result in a truncated comm value. 3.7 /proc/<pid>/task/<tid>/children - Information about task children @@ -2140,6 +2177,22 @@ AVX512_elapsed_ms the task is unlikely an AVX512 user, but depends on the workload and the scheduling scenario, it also could be a false negative mentioned above. +3.13 /proc/<pid>/fd - List of symlinks to open files +------------------------------------------------------- +This directory contains symbolic links which represent open files +the process is maintaining. Example output:: + + lr-x------ 1 root root 64 Sep 20 17:53 0 -> /dev/null + l-wx------ 1 root root 64 Sep 20 17:53 1 -> /dev/null + lrwx------ 1 root root 64 Sep 20 17:53 10 -> 'socket:[12539]' + lrwx------ 1 root root 64 Sep 20 17:53 11 -> 'socket:[12540]' + lrwx------ 1 root root 64 Sep 20 17:53 12 -> 'socket:[12542]' + +The number of open files for the process is stored in 'size' member +of stat() output for /proc/<pid>/fd for fast access. +------------------------------------------------------- + + Chapter 4: Configuring procfs ============================= @@ -2187,7 +2240,7 @@ are not related to tasks. Chapter 5: Filesystem behavior ============================== -Originally, before the advent of pid namepsace, procfs was a global file +Originally, before the advent of pid namespace, procfs was a global file system. It means that there was only one procfs instance in the system. When pid namespace was added, a separate procfs instance was mounted in |