summaryrefslogtreecommitdiff
path: root/Documentation/filesystems
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 05:55:54 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 05:55:54 +0300
commit0e06f5c0deeef0332a5da2ecb8f1fcf3e024d958 (patch)
treee0f0af4aadf10c713c5cf1b65356844b3c9b3215 /Documentation/filesystems
parentf7816ad0f878dacd5f0120476f9b836ccf8699ea (diff)
parent8f19b0c058d93a678a99dd6fec03af2e769943f2 (diff)
downloadlinux-0e06f5c0deeef0332a5da2ecb8f1fcf3e024d958.tar.xz
Merge branch 'akpm' (patches from Andrew)
Merge updates from Andrew Morton: - a few misc bits - ocfs2 - most(?) of MM * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (125 commits) thp: fix comments of __pmd_trans_huge_lock() cgroup: remove unnecessary 0 check from css_from_id() cgroup: fix idr leak for the first cgroup root mm: memcontrol: fix documentation for compound parameter mm: memcontrol: remove BUG_ON in uncharge_list mm: fix build warnings in <linux/compaction.h> mm, thp: convert from optimistic swapin collapsing to conservative mm, thp: fix comment inconsistency for swapin readahead functions thp: update Documentation/{vm/transhuge,filesystems/proc}.txt shmem: split huge pages beyond i_size under memory pressure thp: introduce CONFIG_TRANSPARENT_HUGE_PAGECACHE khugepaged: add support of collapse for tmpfs/shmem pages shmem: make shmem_inode_info::lock irq-safe khugepaged: move up_read(mmap_sem) out of khugepaged_alloc_page() thp: extract khugepaged from mm/huge_memory.c shmem, thp: respect MADV_{NO,}HUGEPAGE for file mappings shmem: add huge pages support shmem: get_unmapped_area align huge page shmem: prepare huge= mount option and sysfs knob mm, rmap: account shmem thp pages ...
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/Locking14
-rw-r--r--Documentation/filesystems/dax.txt6
-rw-r--r--Documentation/filesystems/proc.txt9
-rw-r--r--Documentation/filesystems/vfs.txt11
4 files changed, 33 insertions, 7 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 75eea7ce3d7c..5a7386e38e2d 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -195,7 +195,9 @@ prototypes:
int (*releasepage) (struct page *, int);
void (*freepage)(struct page *);
int (*direct_IO)(struct kiocb *, struct iov_iter *iter);
+ bool (*isolate_page) (struct page *, isolate_mode_t);
int (*migratepage)(struct address_space *, struct page *, struct page *);
+ void (*putback_page) (struct page *);
int (*launder_page)(struct page *);
int (*is_partially_uptodate)(struct page *, unsigned long, unsigned long);
int (*error_remove_page)(struct address_space *, struct page *);
@@ -219,7 +221,9 @@ invalidatepage: yes
releasepage: yes
freepage: yes
direct_IO:
+isolate_page: yes
migratepage: yes (both)
+putback_page: yes
launder_page: yes
is_partially_uptodate: yes
error_remove_page: yes
@@ -544,13 +548,13 @@ subsequent truncate), and then return with VM_FAULT_LOCKED, and the page
locked. The VM will unlock the page.
->map_pages() is called when VM asks to map easy accessible pages.
-Filesystem should find and map pages associated with offsets from "pgoff"
-till "max_pgoff". ->map_pages() is called with page table locked and must
+Filesystem should find and map pages associated with offsets from "start_pgoff"
+till "end_pgoff". ->map_pages() is called with page table locked and must
not block. If it's not possible to reach a page without blocking,
filesystem should skip it. Filesystem should use do_set_pte() to setup
-page table entry. Pointer to entry associated with offset "pgoff" is
-passed in "pte" field in vm_fault structure. Pointers to entries for other
-offsets should be calculated relative to "pte".
+page table entry. Pointer to entry associated with the page is passed in
+"pte" field in fault_env structure. Pointers to entries for other offsets
+should be calculated relative to "pte".
->page_mkwrite() is called when a previously read-only pte is
about to become writeable. The filesystem again must ensure that there are
diff --git a/Documentation/filesystems/dax.txt b/Documentation/filesystems/dax.txt
index ce4587d257d2..0c16a22521a8 100644
--- a/Documentation/filesystems/dax.txt
+++ b/Documentation/filesystems/dax.txt
@@ -49,6 +49,7 @@ These block devices may be used for inspiration:
- axonram: Axon DDR2 device driver
- brd: RAM backed block device driver
- dcssblk: s390 dcss block device driver
+- pmem: NVDIMM persistent memory driver
Implementation Tips for Filesystem Writers
@@ -75,8 +76,9 @@ calls to get_block() (for example by a page-fault racing with a read()
or a write()) work correctly.
These filesystems may be used for inspiration:
-- ext2: the second extended filesystem, see Documentation/filesystems/ext2.txt
-- ext4: the fourth extended filesystem, see Documentation/filesystems/ext4.txt
+- ext2: see Documentation/filesystems/ext2.txt
+- ext4: see Documentation/filesystems/ext4.txt
+- xfs: see Documentation/filesystems/xfs.txt
Handling Media Errors
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 5b61eeae3f6e..68080ad6a75e 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -436,6 +436,7 @@ Private_Dirty: 0 kB
Referenced: 892 kB
Anonymous: 0 kB
AnonHugePages: 0 kB
+ShmemPmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
@@ -464,6 +465,8 @@ 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.
"AnonHugePages" shows the ammount of memory backed by transparent hugepage.
+"ShmemPmdMapped" shows the ammount of shared (shmem/tmpfs) memory backed by
+huge pages.
"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.
@@ -868,6 +871,9 @@ VmallocTotal: 112216 kB
VmallocUsed: 428 kB
VmallocChunk: 111088 kB
AnonHugePages: 49152 kB
+ShmemHugePages: 0 kB
+ShmemPmdMapped: 0 kB
+
MemTotal: Total usable ram (i.e. physical ram minus a few reserved
bits and the kernel binary code)
@@ -912,6 +918,9 @@ MemAvailable: An estimate of how much memory is available for starting new
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
+ShmemHugePages: Memory used by shared memory (shmem) and tmpfs allocated
+ with huge pages
+ShmemPmdMapped: Shared memory mapped into userspace with huge pages
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/vfs.txt b/Documentation/filesystems/vfs.txt
index c61a223ef3ff..900360cbcdae 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -592,9 +592,14 @@ struct address_space_operations {
int (*releasepage) (struct page *, int);
void (*freepage)(struct page *);
ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter);
+ /* isolate a page for migration */
+ bool (*isolate_page) (struct page *, isolate_mode_t);
/* migrate the contents of a page to the specified target */
int (*migratepage) (struct page *, struct page *);
+ /* put migration-failed page back to right list */
+ void (*putback_page) (struct page *);
int (*launder_page) (struct page *);
+
int (*is_partially_uptodate) (struct page *, unsigned long,
unsigned long);
void (*is_dirty_writeback) (struct page *, bool *, bool *);
@@ -747,6 +752,10 @@ struct address_space_operations {
and transfer data directly between the storage and the
application's address space.
+ isolate_page: Called by the VM when isolating a movable non-lru page.
+ If page is successfully isolated, VM marks the page as PG_isolated
+ via __SetPageIsolated.
+
migrate_page: This is used to compact the physical memory usage.
If the VM wants to relocate a page (maybe off a memory card
that is signalling imminent failure) it will pass a new page
@@ -754,6 +763,8 @@ struct address_space_operations {
transfer any private data across and update any references
that it has to the page.
+ putback_page: Called by the VM when isolated page's migration fails.
+
launder_page: Called before freeing a page - it writes back the dirty page. To
prevent redirtying the page, it is kept locked during the whole
operation.