diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/porting | 6 | ||||
| -rw-r--r-- | Documentation/filesystems/proc.txt | 38 | ||||
| -rw-r--r-- | Documentation/filesystems/sharedsubtree.txt | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/tmpfs.txt | 8 | ||||
| -rw-r--r-- | Documentation/filesystems/vfat.txt | 10 |
5 files changed, 45 insertions, 19 deletions
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting index 0f88e6020487..f1b87d8aa2da 100644 --- a/Documentation/filesystems/porting +++ b/Documentation/filesystems/porting @@ -508,7 +508,11 @@ in your dentry operations instead. [mandatory] any symlink that might use page_follow_link_light/page_put_link() must have inode_nohighmem(inode) called before anything might start playing with - its pagecache. + its pagecache. No highmem pages should end up in the pagecache of such + symlinks. That includes any preseeding that might be done during symlink + creation. __page_symlink() will honour the mapping gfp flags, so once + you've done inode_nohighmem() it's safe to use, but if you allocate and + insert the page manually, make sure to use the right gfp flags. -- [mandatory] ->follow_link() is replaced with ->get_link(); same API, except that diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index 402ab99e409f..843b045b4069 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -169,6 +169,9 @@ read the file /proc/PID/status: VmLck: 0 kB VmHWM: 476 kB VmRSS: 476 kB + RssAnon: 352 kB + RssFile: 120 kB + RssShmem: 4 kB VmData: 156 kB VmStk: 88 kB VmExe: 68 kB @@ -231,14 +234,20 @@ Table 1-2: Contents of the status files (as of 4.1) VmSize total program size VmLck locked memory size VmHWM peak resident set size ("high water mark") - VmRSS size of memory portions - VmData size of data, stack, and text segments - VmStk size of data, stack, and text segments + VmRSS size of memory portions. It contains the three + following parts (VmRSS = RssAnon + RssFile + RssShmem) + RssAnon size of resident anonymous memory + RssFile size of resident file mappings + RssShmem size of resident shmem memory (includes SysV shm, + mapping of tmpfs and shared anonymous mappings) + VmData size of private data segments + VmStk size of stack segments 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) + VmSwap amount of swap used by anonymous private data + (shmem swap usage is not included) HugetlbPages size of hugetlb memory portions Threads number of threads SigQ number of signals queued/max. number for queue @@ -265,7 +274,8 @@ Table 1-3: 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) + shared number of pages that are shared (i.e. backed by a file, same + as RssFile+RssShmem in status) 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) @@ -346,7 +356,7 @@ address perms offset dev inode pathname a7cb1000-a7cb2000 ---p 00000000 00:00 0 a7cb2000-a7eb2000 rw-p 00000000 00:00 0 a7eb2000-a7eb3000 ---p 00000000 00:00 0 -a7eb3000-a7ed5000 rw-p 00000000 00:00 0 [stack:1001] +a7eb3000-a7ed5000 rw-p 00000000 00:00 0 a7ed5000-a8008000 r-xp 00000000 03:00 4222 /lib/libc.so.6 a8008000-a800a000 r--p 00133000 03:00 4222 /lib/libc.so.6 a800a000-a800b000 rw-p 00135000 03:00 4222 /lib/libc.so.6 @@ -378,7 +388,6 @@ is not associated with a file: [heap] = the heap of the program [stack] = the stack of the main process - [stack:1001] = the stack of the thread with tid 1001 [vdso] = the "virtual dynamic shared object", the kernel system call handler @@ -386,10 +395,8 @@ is not associated with a file: The /proc/PID/task/TID/maps is a view of the virtual memory from the viewpoint of the individual tasks of a process. In this file you will see a mapping marked -as [stack] if that task sees it as a stack. This is a key difference from the -content of /proc/PID/maps, where you will see all mappings that are being used -as stack by all of those tasks. Hence, for the example above, the task-level -map, i.e. /proc/PID/task/TID/maps for thread 1001 will look like this: +as [stack] if that task sees it as a stack. Hence, for the example above, the +task-level map, i.e. /proc/PID/task/TID/maps for thread 1001 will look like this: 08048000-08049000 r-xp 00000000 03:00 8312 /opt/test 08049000-0804a000 rw-p 00001000 03:00 8312 /opt/test @@ -459,7 +466,10 @@ and a page is modified, the file page is replaced by a private anonymous copy. 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. +For shmem mappings, "Swap" includes also the size of the mapped (and not +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. "VmFlags" field deserves a separate description. This member represents the kernel @@ -807,7 +817,7 @@ by migrate-type and finishes with details on how many page blocks of each type exist. If min_free_kbytes has been tuned correctly (recommendations made by hugeadm -from libhugetlbfs http://sourceforge.net/projects/libhugetlbfs/), one can +from libhugetlbfs https://github.com/libhugetlbfs/libhugetlbfs/), one can make an estimate of the likely number of huge pages that can be allocated at a given point in time. All the "Movable" blocks should be allocatable unless memory has been mlock()'d. Some of the Reclaimable blocks should @@ -842,6 +852,7 @@ Dirty: 968 kB Writeback: 0 kB AnonPages: 861800 kB Mapped: 280372 kB +Shmem: 644 kB Slab: 284364 kB SReclaimable: 159856 kB SUnreclaim: 124508 kB @@ -898,6 +909,7 @@ MemAvailable: An estimate of how much memory is available for starting new AnonPages: Non-file backed pages mapped into userspace page tables AnonHugePages: Non-file backed huge pages mapped into userspace page tables Mapped: files which have been mmaped, such as libraries + Shmem: Total memory used by shared memory (shmem) and tmpfs 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 diff --git a/Documentation/filesystems/sharedsubtree.txt b/Documentation/filesystems/sharedsubtree.txt index 32a173dd3158..e3f4c778eb98 100644 --- a/Documentation/filesystems/sharedsubtree.txt +++ b/Documentation/filesystems/sharedsubtree.txt @@ -664,7 +664,7 @@ replicas continue to be exactly same. if one rbind mounts a tree within the same subtree 'n' times the number of mounts created is an exponential function of 'n'. Having unbindable mount can help prune the unneeded bind - mounts. Here is a example. + mounts. Here is an example. step 1: let's say the root tree has just two directories with diff --git a/Documentation/filesystems/tmpfs.txt b/Documentation/filesystems/tmpfs.txt index 98ef55124158..d392e1505f17 100644 --- a/Documentation/filesystems/tmpfs.txt +++ b/Documentation/filesystems/tmpfs.txt @@ -17,10 +17,10 @@ RAM, where you have to create an ordinary filesystem on top. Ramdisks cannot swap and you do not have the possibility to resize them. Since tmpfs lives completely in the page cache and on swap, all tmpfs -pages currently in memory will show up as cached. It will not show up -as shared or something like that. Further on you can check the actual -RAM+swap use of a tmpfs instance with df(1) and du(1). - +pages will be shown as "Shmem" in /proc/meminfo and "Shared" in +free(1). Notice that these counters also include shared memory +(shmem, see ipcs(1)). The most reliable way to get the count is +using df(1) and du(1). tmpfs has the following uses: diff --git a/Documentation/filesystems/vfat.txt b/Documentation/filesystems/vfat.txt index ce1126aceed8..223c32171dcc 100644 --- a/Documentation/filesystems/vfat.txt +++ b/Documentation/filesystems/vfat.txt @@ -180,6 +180,16 @@ dos1xfloppy -- If set, use a fallback default BIOS Parameter Block <bool>: 0,1,yes,no,true,false +LIMITATION +--------------------------------------------------------------------- +* The fallocated region of file is discarded at umount/evict time + when using fallocate with FALLOC_FL_KEEP_SIZE. + So, User should assume that fallocated region can be discarded at + last close if there is memory pressure resulting in eviction of + the inode from the memory. As a result, for any dependency on + the fallocated region, user should make sure to recheck fallocate + after reopening the file. + TODO ---------------------------------------------------------------------- * Need to get rid of the raw scanning stuff. Instead, always use |
