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This patch introduces run-time migration feature for zspage.
For migration, VM uses page.lru field so it would be better to not use
page.next field which is unified with page.lru for own purpose. For
that, firstly, we can get first object offset of the page via runtime
calculation instead of using page.index so we can use page.index as link
for page chaining instead of page.next.
In case of huge object, it stores handle to page.index instead of next
link of page chaining because huge object doesn't need to next link for
page chaining. So get_next_page need to identify huge object to return
NULL. For it, this patch uses PG_owner_priv_1 flag of the page flag.
For migration, it supports three functions
* zs_page_isolate
It isolates a zspage which includes a subpage VM want to migrate from
class so anyone cannot allocate new object from the zspage.
We could try to isolate a zspage by the number of subpage so subsequent
isolation trial of other subpage of the zpsage shouldn't fail. For
that, we introduce zspage.isolated count. With that, zs_page_isolate
can know whether zspage is already isolated or not for migration so if
it is isolated for migration, subsequent isolation trial can be
successful without trying further isolation.
* zs_page_migrate
First of all, it holds write-side zspage->lock to prevent migrate other
subpage in zspage. Then, lock all objects in the page VM want to
migrate. The reason we should lock all objects in the page is due to
race between zs_map_object and zs_page_migrate.
zs_map_object zs_page_migrate
pin_tag(handle)
obj = handle_to_obj(handle)
obj_to_location(obj, &page, &obj_idx);
write_lock(&zspage->lock)
if (!trypin_tag(handle))
goto unpin_object
zspage = get_zspage(page);
read_lock(&zspage->lock);
If zs_page_migrate doesn't do trypin_tag, zs_map_object's page can be
stale by migration so it goes crash.
If it locks all of objects successfully, it copies content from old page
to new one, finally, create new zspage chain with new page. And if it's
last isolated subpage in the zspage, put the zspage back to class.
* zs_page_putback
It returns isolated zspage to right fullness_group list if it fails to
migrate a page. If it find a zspage is ZS_EMPTY, it queues zspage
freeing to workqueue. See below about async zspage freeing.
This patch introduces asynchronous zspage free. The reason to need it
is we need page_lock to clear PG_movable but unfortunately, zs_free path
should be atomic so the apporach is try to grab page_lock. If it got
page_lock of all of pages successfully, it can free zspage immediately.
Otherwise, it queues free request and free zspage via workqueue in
process context.
If zs_free finds the zspage is isolated when it try to free zspage, it
delays the freeing until zs_page_putback finds it so it will free free
the zspage finally.
In this patch, we expand fullness_list from ZS_EMPTY to ZS_FULL. First
of all, it will use ZS_EMPTY list for delay freeing. And with adding
ZS_FULL list, it makes to identify whether zspage is isolated or not via
list_empty(&zspage->list) test.
[minchan@kernel.org: zsmalloc: keep first object offset in struct page]
Link: http://lkml.kernel.org/r/1465788015-23195-1-git-send-email-minchan@kernel.org
[minchan@kernel.org: zsmalloc: zspage sanity check]
Link: http://lkml.kernel.org/r/20160603010129.GC3304@bbox
Link: http://lkml.kernel.org/r/1464736881-24886-12-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Now, VM has a feature to migrate non-lru movable pages so balloon
doesn't need custom migration hooks in migrate.c and compaction.c.
Instead, this patch implements the page->mapping->a_ops->
{isolate|migrate|putback} functions.
With that, we could remove hooks for ballooning in general migration
functions and make balloon compaction simple.
[akpm@linux-foundation.org: compaction.h requires that the includer first include node.h]
Link: http://lkml.kernel.org/r/1464736881-24886-4-git-send-email-minchan@kernel.org
Signed-off-by: Gioh Kim <gi-oh.kim@profitbricks.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Currently UDF superblock magic doesn't appear in any userspace header
files and thus userspace apps have hard time checking for this fs. Let's
export the magic to userspace as with any other filesystem.
Signed-off-by: Jan Kara <jack@suse.cz>
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git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs updates from Miklos Szeredi:
"This contains several bug fixes and a new mount option
'default_permissions' that allows read-only exported NFS
filesystems to be used as lower layer"
* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
ovl: check dentry positiveness in ovl_cleanup_whiteouts()
ovl: setattr: check permissions before copy-up
ovl: root: copy attr
ovl: move super block magic number to magic.h
ovl: use a minimal buffer in ovl_copy_xattr
ovl: allow zero size xattr
ovl: default permissions
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With major controllers - cpu, memory and io - shaping up for the
unified hierarchy, cgroup2 is about ready to be, gradually, released
into the wild. Replace __DEVEL__sane_behavior flag which was used to
select the unified hierarchy with a separate filesystem type "cgroup2"
so that unified hierarchy can be mounted as follows.
mount -t cgroup2 none $MOUNT_POINT
The cgroup2 fs has its own magic number - 0x63677270 ("cgrp").
v2: Assign a different magic number to cgroup2 fs.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
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The overlayfs file system is not recognized by programs
like tail because the magic number is not in standard header location.
Move it so that the value will propagate on for the GNU library
and utilities. Needs to go in the fstatfs manual page as well.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
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This work adds support for "persistent" eBPF maps/programs. The term
"persistent" is to be understood that maps/programs have a facility
that lets them survive process termination. This is desired by various
eBPF subsystem users.
Just to name one example: tc classifier/action. Whenever tc parses
the ELF object, extracts and loads maps/progs into the kernel, these
file descriptors will be out of reach after the tc instance exits.
So a subsequent tc invocation won't be able to access/relocate on this
resource, and therefore maps cannot easily be shared, f.e. between the
ingress and egress networking data path.
The current workaround is that Unix domain sockets (UDS) need to be
instrumented in order to pass the created eBPF map/program file
descriptors to a third party management daemon through UDS' socket
passing facility. This makes it a bit complicated to deploy shared
eBPF maps or programs (programs f.e. for tail calls) among various
processes.
We've been brainstorming on how we could tackle this issue and various
approches have been tried out so far, which can be read up further in
the below reference.
The architecture we eventually ended up with is a minimal file system
that can hold map/prog objects. The file system is a per mount namespace
singleton, and the default mount point is /sys/fs/bpf/. Any subsequent
mounts within a given namespace will point to the same instance. The
file system allows for creating a user-defined directory structure.
The objects for maps/progs are created/fetched through bpf(2) with
two new commands (BPF_OBJ_PIN/BPF_OBJ_GET). I.e. a bpf file descriptor
along with a pathname is being passed to bpf(2) that in turn creates
(we call it eBPF object pinning) the file system nodes. Only the pathname
is being passed to bpf(2) for getting a new BPF file descriptor to an
existing node. The user can use that to access maps and progs later on,
through bpf(2). Removal of file system nodes is being managed through
normal VFS functions such as unlink(2), etc. The file system code is
kept to a very minimum and can be further extended later on.
The next step I'm working on is to add dump eBPF map/prog commands
to bpf(2), so that a specification from a given file descriptor can
be retrieved. This can be used by things like CRIU but also applications
can inspect the meta data after calling BPF_OBJ_GET.
Big thanks also to Alexei and Hannes who significantly contributed
in the design discussion that eventually let us end up with this
architecture here.
Reference: https://lkml.org/lkml/2015/10/15/925
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Add a separate file system to handle the tracing directory. Currently it
is part of debugfs, but that is starting to show its limits.
One thing is that in order to access the tracing infrastructure, you need
to mount debugfs. As that includes debugging from all sorts of sub systems
in the kernel, it is not considered advisable to mount such an all
encompassing debugging system.
Having the tracing system in its own file systems gives access to the
tracing sub system without needing to include all other systems.
Another problem with tracing using the debugfs system is that the
instances use mkdir to create sub buffers. debugfs does not support mkdir
from userspace so to implement it, special hacks were used. By controlling
the file system that the tracing infrastructure uses, this can be properly
done without hacks.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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New pseudo-filesystem: nsfs. Targets of /proc/*/ns/* live there now.
It's not mountable (not even registered, so it's not in /proc/filesystems,
etc.). Files on it *are* bindable - we explicitly permit that in do_loopback().
This stuff lives in fs/nsfs.c now; proc_ns_fget() moved there as well.
get_proc_ns() is a macro now (it's simply returning ->i_private; would
have been an inline, if not for header ordering headache).
proc_ns_inode() is an ex-parrot. The interface used in procfs is
ns_get_path(path, task, ops) and ns_get_name(buf, size, task, ops).
Dentries and inodes are never hashed; a non-counting reference to dentry
is stashed in ns_common (removed by ->d_prune()) and reused by ns_get_path()
if present. See ns_get_path()/ns_prune_dentry/nsfs_evict() for details
of that mechanism.
As the result, proc_ns_follow_link() has stopped poking in nd->path.mnt;
it does nd_jump_link() on a consistent <vfsmount,dentry> pair it gets
from ns_get_path().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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So both Liu and I made huge messes of find_lock_delalloc_range trying to fix
stuff, me first by fixing extent size, then him by fixing something I broke and
then me again telling him to fix it a different way. So this is obviously a
candidate for some testing. This patch adds a pseudo fs so we can allocate fake
inodes for tests that need an inode or pages. Then it addes a bunch of tests to
make sure find_lock_delalloc_range is acting the way it is supposed to. With
this patch and all of our previous patches to find_lock_delalloc_range I am sure
it is working as expected now. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
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Move HOSTFS_SUPER_MAGIC to <linux/magic.h> to be with it's magical
friends from other file systems.
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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SMACK_MAGIC moved to a proper place for easy user space access
(i.e. libsmack).
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@iki.fi>
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git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs
Pull new F2FS filesystem from Jaegeuk Kim:
"Introduce a new file system, Flash-Friendly File System (F2FS), to
Linux 3.8.
Highlights:
- Add initial f2fs source codes
- Fix an endian conversion bug
- Fix build failures on random configs
- Fix the power-off-recovery routine
- Minor cleanup, coding style, and typos patches"
From the Kconfig help text:
F2FS is based on Log-structured File System (LFS), which supports
versatile "flash-friendly" features. The design has been focused on
addressing the fundamental issues in LFS, which are snowball effect
of wandering tree and high cleaning overhead.
Since flash-based storages show different characteristics according to
the internal geometry or flash memory management schemes aka FTL, F2FS
and tools support various parameters not only for configuring on-disk
layout, but also for selecting allocation and cleaning algorithms.
and there's an article by Neil Brown about it on lwn.net:
http://lwn.net/Articles/518988/
* tag 'for-3.8-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (36 commits)
f2fs: fix tracking parent inode number
f2fs: cleanup the f2fs_bio_alloc routine
f2fs: introduce accessor to retrieve number of dentry slots
f2fs: remove redundant call to f2fs_put_page in delete entry
f2fs: make use of GFP_F2FS_ZERO for setting gfp_mask
f2fs: rewrite f2fs_bio_alloc to make it simpler
f2fs: fix a typo in f2fs documentation
f2fs: remove unused variable
f2fs: move error condition for mkdir at proper place
f2fs: remove unneeded initialization
f2fs: check read only condition before beginning write out
f2fs: remove unneeded memset from init_once
f2fs: show error in case of invalid mount arguments
f2fs: fix the compiler warning for uninitialized use of variable
f2fs: resolve build failures
f2fs: adjust kernel coding style
f2fs: fix endian conversion bugs reported by sparse
f2fs: remove unneeded version.h header file from f2fs.h
f2fs: update the f2fs document
f2fs: update Kconfig and Makefile
...
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This adds the following major in-memory structures in f2fs.
- f2fs_sb_info:
contains f2fs-specific information, two special inode pointers for node and
meta address spaces, and orphan inode management.
- f2fs_inode_info:
contains vfs_inode and other fs-specific information.
- f2fs_nm_info:
contains node manager information such as NAT entry cache, free nid list,
and NAT page management.
- f2fs_node_info:
represents a node as node id, inode number, block address, and its version.
- f2fs_sm_info:
contains segment manager information such as SIT entry cache, free segment
map, current active logs, dirty segment management, and segment utilization.
The specific structures are sit_info, free_segmap_info, dirty_seglist_info,
curseg_info.
In addition, add F2FS_SUPER_MAGIC in magic.h.
Signed-off-by: Chul Lee <chur.lee@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
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Using pstore's superblock magic number is no doubt going to cause
problems in the future. Give efivarfs its own magic number.
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
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Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>
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