OrgACRN
/
acrn-kernel
mirror of https://github.com/projectacrn/acrn-kernel.git
1
0
Fork 0
Code Issues Releases Wiki Activity
acrn-kernel/fs
History
Peter Zijlstra f5d39b0208 freezer,sched: Rewrite core freezer logic 
Rewrite the core freezer to behave better wrt thawing and be simpler
in general.

By replacing PF_FROZEN with TASK_FROZEN, a special block state, it is
ensured frozen tasks stay frozen until thawed and don't randomly wake
up early, as is currently possible.

As such, it does away with PF_FROZEN and PF_FREEZER_SKIP, freeing up
two PF_flags (yay!).

Specifically; the current scheme works a little like:

	freezer_do_not_count();
	schedule();
	freezer_count();

And either the task is blocked, or it lands in try_to_freezer()
through freezer_count(). Now, when it is blocked, the freezer
considers it frozen and continues.

However, on thawing, once pm_freezing is cleared, freezer_count()
stops working, and any random/spurious wakeup will let a task run
before its time.

That is, thawing tries to thaw things in explicit order; kernel
threads and workqueues before doing bringing SMP back before userspace
etc.. However due to the above mentioned races it is entirely possible
for userspace tasks to thaw (by accident) before SMP is back.

This can be a fatal problem in asymmetric ISA architectures (eg ARMv9)
where the userspace task requires a special CPU to run.

As said; replace this with a special task state TASK_FROZEN and add
the following state transitions:

	TASK_FREEZABLE	-> TASK_FROZEN
	__TASK_STOPPED	-> TASK_FROZEN
	__TASK_TRACED	-> TASK_FROZEN

The new TASK_FREEZABLE can be set on any state part of TASK_NORMAL
(IOW. TASK_INTERRUPTIBLE and TASK_UNINTERRUPTIBLE) -- any such state
is already required to deal with spurious wakeups and the freezer
causes one such when thawing the task (since the original state is
lost).

The special __TASK_{STOPPED,TRACED} states *can* be restored since
their canonical state is in ->jobctl.

With this, frozen tasks need an explicit TASK_FROZEN wakeup and are
free of undue (early / spurious) wakeups.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20220822114649.055452969@infradead.org
 		2022-09-07 21:53:50 +02:00
..
9p 9p: Fix some kernel-doc comments 2022-07-02 18:52:21 +09:00
adfs
…
affs affs: use memcpy_to_page and remove replace kmap_atomic() 2022-08-01 19:53:31 +02:00
afs AFS fixes 2022-08-09 10:08:08 -07:00
autofs autofs: remove unused ino field inode 2022-07-17 17:31:42 -07:00
befs befs: Convert befs_symlink_read_folio() to use a folio 2022-08-02 12:34:03 -04:00
bfs
…
btrfs - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
cachefiles cachefiles: narrow the scope of flushed requests when releasing fd 2022-07-05 16:12:21 +01:00
ceph fs.setgid.v6.0 2022-08-09 09:52:28 -07:00
cifs freezer,sched: Rewrite core freezer logic 2022-09-07 21:53:50 +02:00
coda coda: Convert coda_symlink_filler() to use a folio 2022-08-02 12:34:03 -04:00
configfs
…
cramfs cramfs: read_mapping_page() is synchronous 2022-08-02 12:34:02 -04:00
crypto fscrypt: Add HCTR2 support for filename encryption 2022-06-10 16:40:18 +08:00
debugfs
…
devpts
…
dlm fs: dlm: move kref_put assert for lkb structs 2022-08-01 09:31:46 -05:00
ecryptfs
…
efivarfs efi: vars: Move efivar caching layer into efivarfs 2022-06-24 20:40:19 +02:00
efs
…
erofs - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
exfat exfat: Drop superfluous new line for error messages 2022-08-01 10:14:07 +09:00
exportfs
…
ext2 - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
ext4 - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
f2fs f2fs-for-6.0 2022-08-08 11:18:31 -07:00
fat Updates to various subsystems which I help look after. lib, ocfs2, 2022-08-07 10:03:24 -07:00
freevxfs freevxfs: Convert vxfs_immed_read_folio() to use a folio 2022-08-02 12:34:03 -04:00
fscache fscache: add tracepoint when failing cookie 2022-08-09 14:13:59 +01:00
fuse iov_iter stuff, part 2, rebased 2022-08-08 20:04:35 -07:00
gfs2 iov_iter stuff, part 2, rebased 2022-08-08 20:04:35 -07:00
hfs hfs: Remove check for PageError 2022-06-29 08:51:06 -04:00
hfsplus Folio changes for 6.0 2022-08-03 10:35:43 -07:00
hostfs hostfs: Handle page write errors correctly 2022-08-02 12:34:02 -04:00
hpfs
…
hugetlbfs iov_iter stuff, part 2, rebased 2022-08-08 20:04:35 -07:00
iomap new iov_iter flavour - ITER_UBUF 2022-08-08 22:37:15 -04:00
isofs fs/buffer: Combine two submit_bh() and ll_rw_block() arguments 2022-07-14 12:14:32 -06:00
jbd2 - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
jffs2 This pull request contains fixes for JFFS2, UBI and UBIFS 2022-06-03 14:42:24 -07:00
jfs Folio changes for 6.0 2022-08-03 10:35:43 -07:00
kernfs kernfs: Fix typo 'the the' in comment 2022-07-28 10:57:25 +02:00
ksmbd 12 server fixes, including for oopses, memory leaks and adding a channel lock 2022-08-08 20:15:13 -07:00
lockd lockd: detect and reject lock arguments that overflow 2022-08-04 10:28:48 -04:00
minix
…
netfs netfs: do not unlock and put the folio twice 2022-07-14 10:10:12 +02:00
nfs freezer,sched: Rewrite core freezer logic 2022-09-07 21:53:50 +02:00
nfs_common
…
nfsd NFSD 6.0 Release Notes 2022-08-09 14:56:49 -07:00
nilfs2 Folio changes for 6.0 2022-08-03 10:35:43 -07:00
nls
…
notify fsnotify: Fix comment typo 2022-07-26 13:38:47 +02:00
ntfs Folio changes for 6.0 2022-08-03 10:35:43 -07:00
ntfs3 Folio changes for 6.0 2022-08-03 10:35:43 -07:00
ocfs2 fs.setgid.v6.0 2022-08-09 09:52:28 -07:00
omfs
…
openpromfs
…
orangefs orangefs: Remove test for folio error 2022-06-29 08:51:07 -04:00
overlayfs overlayfs update for 6.0 2022-08-08 11:03:11 -07:00
proc Updates to various subsystems which I help look after. lib, ocfs2, 2022-08-07 10:03:24 -07:00
pstore EFI updates for v5.20 2022-08-03 14:38:02 -07:00
qnx4
…
qnx6
…
quota - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
ramfs Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
reiserfs Folio changes for 6.0 2022-08-03 10:35:43 -07:00
romfs
…
smbfs_common
…
squashfs Updates to various subsystems which I help look after. lib, ocfs2, 2022-08-07 10:03:24 -07:00
sysfs
…
sysv Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
tracefs tracefs: Fix syntax errors in comments 2022-06-17 19:01:28 -04:00
ubifs - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
udf fs/buffer: Combine two submit_bh() and ll_rw_block() arguments 2022-07-14 12:14:32 -06:00
ufs Folio changes for 6.0 2022-08-03 10:35:43 -07:00
unicode
…
vboxsf
…
verity fs-verity: mention btrfs support 2022-07-15 23:42:30 -07:00
xfs freezer,sched: Rewrite core freezer logic 2022-09-07 21:53:50 +02:00
zonefs zonefs changes for 5.20-rc1 2022-08-03 15:21:53 -07:00
Kconfig mm: hugetlb_vmemmap: introduce the name HVO 2022-08-08 18:06:42 -07:00
Kconfig.binfmt m68knommu: changes for linux 5.19 2022-05-30 10:56:18 -07:00
Makefile io_uring: move to separate directory 2022-07-24 18:39:10 -06:00
aio.c iov_iter work, part 1 - isolated cleanups and optimizations. 2022-08-03 13:50:22 -07:00
anon_inodes.c
…
attr.c vfs: Check the truncate maximum size in inode_newsize_ok() 2022-08-08 10:39:29 -07:00
bad_inode.c
…
binfmt_aout.c
…
binfmt_elf.c
…
binfmt_elf_fdpic.c
…
binfmt_elf_test.c
…
binfmt_flat.c
…
binfmt_misc.c
…
binfmt_script.c
…
buffer.c Folio changes for 6.0 2022-08-03 10:35:43 -07:00
char_dev.c
…
compat_binfmt_elf.c
…
coredump.c freezer,sched: Rewrite core freezer logic 2022-09-07 21:53:50 +02:00
d_path.c
…
dax.c - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
dcache.c fs/dcache: Move wakeup out of i_seq_dir write held region. 2022-07-30 00:38:16 -04:00
direct-io.c iov_iter: advancing variants of iov_iter_get_pages{,_alloc}() 2022-08-08 22:37:22 -04:00
drop_caches.c
…
eventfd.c
…
eventpoll.c epoll: autoremove wakers even more aggressively 2022-07-17 17:31:40 -07:00
exec.c execve updates for v5.20-rc1 2022-08-02 14:36:19 -07:00
fcntl.c keep iocb_flags() result cached in struct file 2022-06-10 16:10:23 -04:00
fhandle.c
…
file.c fix the breakage in close_fd_get_file() calling conventions change 2022-06-05 15:03:03 -04:00
file_table.c iov_iter work, part 1 - isolated cleanups and optimizations. 2022-08-03 13:50:22 -07:00
filesystems.c
…
fs-writeback.c writeback: Fix inode->i_io_list not be protected by inode->i_lock error 2022-06-06 09:54:30 +02:00
fs_context.c
…
fs_parser.c
…
fs_pin.c
…
fs_struct.c
…
fs_types.c
…
fsopen.c
…
init.c
…
inode.c fs.setgid.v6.0 2022-08-09 09:52:28 -07:00
internal.h Cleanups (and one fix) around struct mount handling. 2022-06-04 19:00:05 -07:00
ioctl.c
…
kernel_read_file.c fs/kernel_read_file: allow to read files up-to ssize_t 2022-06-16 19:58:21 -07:00
libfs.c
…
locks.c fs/lock: Rearrange ops in flock syscall. 2022-07-18 10:01:47 -04:00
mbcache.c - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
mount.h switch try_to_unlazy_next() to __legitimize_mnt() 2022-07-05 16:18:21 -04:00
mpage.c Folio changes for 6.0 2022-08-03 10:35:43 -07:00
namei.c fs.setgid.v6.0 2022-08-09 09:52:28 -07:00
namespace.c switch try_to_unlazy_next() to __legitimize_mnt() 2022-07-05 16:18:21 -04:00
no-block.c
…
nsfs.c
…
open.c iov_iter work, part 1 - isolated cleanups and optimizations. 2022-08-03 13:50:22 -07:00
pipe.c Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
pnode.c
…
pnode.h
…
posix_acl.c acl: make posix_acl_clone() available to overlayfs 2022-07-15 22:09:57 +02:00
proc_namespace.c
…
read_write.c switch new_sync_{read,write}() to ITER_UBUF 2022-08-08 22:37:15 -04:00
readdir.c
…
remap_range.c - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
select.c
…
seq_file.c
…
signalfd.c
…
splice.c iter_to_pipe(): switch to advancing variant of iov_iter_get_pages() 2022-08-08 22:37:23 -04:00
stack.c
…
stat.c RISC-V Patches for the 5.19 Merge Window, Part 1 2022-05-31 14:10:54 -07:00
statfs.c
…
super.c fuse update for 6.0 2022-08-08 11:10:02 -07:00
sync.c
…
sysctls.c
…
timerfd.c
…
userfaultfd.c - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe 2022-08-05 16:32:45 -07:00
utimes.c
…
xattr.c acl: move idmapped mount fixup into vfs_{g,s}etxattr() 2022-07-15 22:08:59 +02:00