diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/filesystems/Locking | 24 | ||||
| -rw-r--r-- | Documentation/kernel-doc-nano-HOWTO.txt | 7 | ||||
| -rw-r--r-- | Documentation/sysctl/vm.txt | 4 |
3 files changed, 25 insertions, 10 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 76efe5b71d7d..3120f8dd2c31 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -512,16 +512,24 @@ locking rules: BKL mmap_sem PageLocked(page) open: no yes close: no yes -fault: no yes -page_mkwrite: no yes no +fault: no yes can return with page locked +page_mkwrite: no yes can return with page locked access: no yes - ->page_mkwrite() is called when a previously read-only page is -about to become writeable. The file system is responsible for -protecting against truncate races. Once appropriate action has been -taking to lock out truncate, the page range should be verified to be -within i_size. The page mapping should also be checked that it is not -NULL. + ->fault() is called when a previously not present pte is about +to be faulted in. The filesystem must find and return the page associated +with the passed in "pgoff" in the vm_fault structure. If it is possible that +the page may be truncated and/or invalidated, then the filesystem must lock +the page, then ensure it is not already truncated (the page lock will block +subsequent truncate), and then return with VM_FAULT_LOCKED, and the page +locked. The VM will unlock the page. + + ->page_mkwrite() is called when a previously read-only pte is +about to become writeable. The filesystem again must ensure that there are +no truncate/invalidate races, and then return with the page locked. If +the page has been truncated, the filesystem should not look up a new page +like the ->fault() handler, but simply return with VM_FAULT_NOPAGE, which +will cause the VM to retry the fault. ->access() is called when get_user_pages() fails in acces_process_vm(), typically used to debug a process through diff --git a/Documentation/kernel-doc-nano-HOWTO.txt b/Documentation/kernel-doc-nano-HOWTO.txt index 026ec7d57384..4d04572b6549 100644 --- a/Documentation/kernel-doc-nano-HOWTO.txt +++ b/Documentation/kernel-doc-nano-HOWTO.txt @@ -269,7 +269,10 @@ Use the argument mechanism to document members or constants. Inside a struct description, you can use the "private:" and "public:" comment tags. Structure fields that are inside a "private:" area -are not listed in the generated output documentation. +are not listed in the generated output documentation. The "private:" +and "public:" tags must begin immediately following a "/*" comment +marker. They may optionally include comments between the ":" and the +ending "*/" marker. Example: @@ -283,7 +286,7 @@ Example: struct my_struct { int a; int b; -/* private: */ +/* private: internal use only */ int c; }; diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index 97c4b3284329..b716d33912d8 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -90,6 +90,10 @@ will itself start writeback. If dirty_bytes is written, dirty_ratio becomes a function of its value (dirty_bytes / the amount of dirtyable system memory). +Note: the minimum value allowed for dirty_bytes is two pages (in bytes); any +value lower than this limit will be ignored and the old configuration will be +retained. + ============================================================== dirty_expire_centisecs |