diff options
Diffstat (limited to 'kernel/Documentation/filesystems/proc.txt')
| -rw-r--r-- | kernel/Documentation/filesystems/proc.txt | 68 |
1 files changed, 43 insertions, 25 deletions
diff --git a/kernel/Documentation/filesystems/proc.txt b/kernel/Documentation/filesystems/proc.txt index c3b6b301d..402ab99e4 100644 --- a/kernel/Documentation/filesystems/proc.txt +++ b/kernel/Documentation/filesystems/proc.txt @@ -140,7 +140,8 @@ Table 1-1: Process specific entries in /proc 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 + wchan Present with CONFIG_KALLSYMS=y: it shows the kernel function + symbol the task is blocked in - or "0" if not blocked. pagemap Page table stack Report full stack trace, enable via CONFIG_STACKTRACE smaps a extension based on maps, showing the memory consumption of @@ -174,6 +175,7 @@ read the file /proc/PID/status: VmLib: 1412 kB VmPTE: 20 kb VmSwap: 0 kB + HugetlbPages: 0 kB Threads: 1 SigQ: 0/28578 SigPnd: 0000000000000000 @@ -205,7 +207,7 @@ 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 1-2: Contents of the status files (as of 3.20.0) +Table 1-2: Contents of the status files (as of 4.1) .............................................................................. Field Content Name filename of the executable @@ -235,7 +237,9 @@ Table 1-2: Contents of the status files (as of 3.20.0) VmExe size of text segment VmLib size of shared library code VmPTE size of page table entries + VmPMD size of second level page tables VmSwap size of swap usage (the number of referred swapents) + HugetlbPages size of hugetlb memory portions Threads number of threads SigQ number of signals queued/max. number for queue SigPnd bitmap of pending signals for the thread @@ -309,7 +313,7 @@ Table 1-4: Contents of the stat files (as of 2.6.30-rc7) blocked bitmap of blocked signals sigign bitmap of ignored signals sigcatch bitmap of caught signals - wchan address where process went to sleep + 0 (place holder, used to be the wchan address, use /proc/PID/wchan instead) 0 (place holder) 0 (place holder) exit_signal signal to send to parent thread on exit @@ -422,25 +426,41 @@ Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 892 kB Anonymous: 0 kB +AnonHugePages: 0 kB +Shared_Hugetlb: 0 kB +Private_Hugetlb: 0 kB Swap: 0 kB +SwapPss: 0 kB KernelPageSize: 4 kB MMUPageSize: 4 kB -Locked: 374 kB -VmFlags: rd ex mr mw me de +Locked: 0 kB +VmFlags: rd ex mr mw me dw the first of these lines shows the same information as is displayed for the mapping in /proc/PID/maps. The remaining lines show the size of the mapping (size), the amount of the mapping that is currently resident in RAM (RSS), the process' proportional share of this mapping (PSS), the number of clean and -dirty private pages in the mapping. 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 as private and not as shared. "Referenced" -indicates the amount of memory currently marked as referenced or accessed. +dirty 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. +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 +as private and not as shared. +"Referenced" indicates the amount of memory currently marked as referenced or +accessed. "Anonymous" shows the amount of memory that does not belong to any file. Even 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. -"Swap" shows how much would-be-anonymous memory is also used, but out on -swap. +"AnonHugePages" shows the ammount of memory backed by transparent hugepage. +"Shared_Hugetlb" and "Private_Hugetlb" show the ammounts 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. +"Swap" shows how much would-be-anonymous memory is also used, but out on swap. +"SwapPss" shows proportional swap share of this mapping. +"Locked" indicates whether the mapping is locked in memory or not. "VmFlags" field deserves a separate description. This member represents the kernel flags associated with the particular virtual memory area in two letter encoded @@ -465,7 +485,6 @@ manner. The codes are the following: ac - area is accountable nr - swap space is not reserved for the area ht - area uses huge tlb pages - nl - non-linear mapping ar - architecture specific flag dd - do not include area into core dump sd - soft-dirty flag @@ -805,9 +824,6 @@ varies by architecture and compile options. The following is from a > cat /proc/meminfo -The "Locked" indicates whether the mapping is locked in memory or not. - - MemTotal: 16344972 kB MemFree: 13634064 kB MemAvailable: 14836172 kB @@ -1589,16 +1605,16 @@ Documentation/accounting. --------------------------------------------------------------- When a process is dumped, all anonymous memory is written to a core file as long as the size of the core file isn't limited. But sometimes we don't want -to dump some memory segments, for example, huge shared memory. Conversely, -sometimes we want to save file-backed memory segments into a core file, not -only the individual files. +to dump some memory segments, for example, huge shared memory or DAX. +Conversely, sometimes we want to save file-backed memory segments into a core +file, not only the individual files. /proc/<pid>/coredump_filter allows you to customize which memory segments will be dumped when the <pid> process is dumped. coredump_filter is a bitmask of memory types. If a bit of the bitmask is set, memory segments of the corresponding memory type are dumped, otherwise they are not dumped. -The following 7 memory types are supported: +The following 9 memory types are supported: - (bit 0) anonymous private memory - (bit 1) anonymous shared memory - (bit 2) file-backed private memory @@ -1607,20 +1623,22 @@ The following 7 memory types are supported: effective only if the bit 2 is cleared) - (bit 5) hugetlb private memory - (bit 6) hugetlb shared memory + - (bit 7) DAX private memory + - (bit 8) DAX shared memory Note that MMIO pages such as frame buffer are never dumped and vDSO pages are always dumped regardless of the bitmask status. - Note bit 0-4 doesn't effect any hugetlb memory. hugetlb memory are only - effected by bit 5-6. + Note that bits 0-4 don't affect hugetlb or DAX memory. hugetlb memory is + only affected by bit 5-6, and DAX is only affected by bits 7-8. -Default value of coredump_filter is 0x23; this means all anonymous memory -segments and hugetlb private memory are dumped. +The default value of coredump_filter is 0x33; this means all anonymous memory +segments, ELF header pages and hugetlb private memory are dumped. If you don't want to dump all shared memory segments attached to pid 1234, -write 0x21 to the process's proc file. +write 0x31 to the process's proc file. - $ echo 0x21 > /proc/1234/coredump_filter + $ echo 0x31 > /proc/1234/coredump_filter When a new process is created, the process inherits the bitmask status from its parent. It is useful to set up coredump_filter before the program runs. |