Artem Bityutskiy [Thu, 31 May 2012 23:26:12 +0000 (16:26 -0700)]
fat: introduce special inode for managing the FSINFO block
This is patchset makes fatfs stop using the VFS '->write_super()' method
for writing out the FSINFO block.
The final goal is to get rid of the 'sync_supers()' kernel thread. This
kernel thread wakes up every 5 seconds (by default) and calls
'->write_super()' for all mounted file-systems. And the bad thing is that
this is done even if all the superblocks are clean. Moreover, some
file-systems do not even need this end they do not register the
'->write_super()' method at all (e.g., btrfs).
So 'sync_supers()' most often just generates useless wake-ups and wastes
power. I am trying to make all file-systems independent of
'->write_super()' and plan to remove 'sync_supers()' and '->write_super'
completely once there are no more users.
The '->write_supers()' method is mostly used by baroque file-systems like
hfs, udf, etc. Modern file-systems like btrfs and xfs do not use it.
This justifies removing this stuff from VFS completely and make every FS
self-manage own superblock.
Tested with xfstests.
This patch:
Preparation for further changes. It introduces a special inode
('fsinfo_inode') in FAT file-system which we'll later use for managing the
FSINFO block. Note, this there is already one special inode ('fat_inode')
which is used for managing the FAT tables.
Introduce new 'MSDOS_FSINFO_INO' constant for this special inode. It is
safe to do because FAT file-system does not store inode numbers on the
media but generates them run-time.
I've also cleaned up the comment to existing 'MSDOS_ROOT_INO' constant,
while on it.
Ryusuke Konishi [Thu, 31 May 2012 23:26:11 +0000 (16:26 -0700)]
nilfs2: flush disk caches in syncing
There are two cases that the cache flush is needed to avoid data loss
against unexpected hang or power failure. One is sync file function (i.e.
nilfs_sync_file) and another is checkpointing ioctl.
This issues a cache flush request to device for such cases if barrier
mount option is enabled, and makes sure data really is on persistent
storage on their completion.
Will Deacon [Thu, 31 May 2012 23:26:10 +0000 (16:26 -0700)]
pipe: return -ENOIOCTLCMD instead of -EINVAL on unknown ioctl command
As described in commit 07d106d0a33d ("vfs: fix up ENOIOCTLCMD error
handling"), drivers should return -ENOIOCTLCMD if they receive an ioctl
command which they don't understand. Doing so will result in -ENOTTY
being returned to userspace, which matches the behaviour of the compat
layer if it fails to translate an ioctl command.
This patch fixes the pipe ioctl to return -ENOIOCTLCMD instead of -EINVAL
when passed an unknown ioctl command.
init: disable sparse checking of the mount.o source files
The init/mount.o source files produce a number of sparse warnings of the
type:
warning: incorrect type in argument 1 (different address spaces)
expected char [noderef] <asn:1>*dev_name
got char *name
This is due to the syscalls expecting some of the arguments to be user
pointers but they are being passed as kernel pointers. This is harmless
but adds a lot of noise to a sparse build.
To limit the noise just disable the sparse checking in the relevant source
files, but still display a warning so that the user knows this has been
done.
Since the sparse checking has been disabled we can also remove the __user
__force casts that are scattered thru the source.
Denys Vlasenko [Thu, 31 May 2012 23:26:08 +0000 (16:26 -0700)]
vsprintf: further optimize decimal conversion
Previous code was using optimizations which were developed to work well
even on narrow-word CPUs (by today's standards). But Linux runs only on
32-bit and wider CPUs. We can use that.
First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly
divide by 10 much larger numbers, and thus we can print groups of 9 digits
instead of groups of 5 digits.
Next: there are two algorithms to print larger numbers. One is generic:
divide by 1000000000 and repeatedly print groups of (up to) 9 digits.
It's conceptually simple, but requires an (unsigned long long) / 1000000000 division.
Second algorithm splits 64-bit unsigned long long into 16-bit chunks,
manipulates them cleverly and generates groups of 4 decimal digits. It so
happens that it does NOT require long long division.
If long is > 32 bits, division of 64-bit values is relatively easy, and we
will use the first algorithm. If long long is > 64 bits (strange
architecture with VERY large long long), second algorithm can't be used,
and we again use the first one.
Else (if long is 32 bits and long long is 64 bits) we use second one.
And third: there is a simple optimization which takes fast path not only
for zero as was done before, but for all one-digit numbers.
In all tested cases new code is faster than old one, in many cases by 30%,
in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit
case.
This patch is based upon an original from Michal Nazarewicz.
Grant Likely [Thu, 31 May 2012 23:26:08 +0000 (16:26 -0700)]
vsprintf: correctly handle width when '#' flag used in %#p format
The '%p' output of the kernel's vsprintf() uses spec.field_width to
determine how many digits to output based on 2 * sizeof(void*) so that all
digits of a pointer are shown. ie. a pointer will be output as
"001A2B3C" instead of "1A2B3C". However, if the '#' flag is used in the
format (%#p), then the code doesn't take into account the width of the
'0x' prefix and will end up outputing "0x1A2B3C" instead of "0x001A2B3C".
This patch reworks the "pointer()" format hook to include 2 characters for
the '0x' prefix if the '#' flag is included.
Sasikantha babu [Thu, 31 May 2012 23:26:07 +0000 (16:26 -0700)]
sethostname/setdomainname: notify userspace when there is a change in uts_kern_table
sethostname() and setdomainname() notify userspace on failure (without
modifying uts_kern_table). Change things so that we only notify userspace
on success, when uts_kern_table was actually modified.
Sergei Shtylyov [Thu, 31 May 2012 23:26:06 +0000 (16:26 -0700)]
drivers/message/fusion: use pci_dev->revision
This driver uses PCI_CLASS_REVISION instead of PCI_REVISION_ID, so it
wasn't converted by 44c10138fd4bbc ("PCI: Change all drivers to use
pci_device->revision").
In one case, it even reads PCI revision ID without using it -- that code
is now removed...
Xi Wang [Thu, 31 May 2012 23:26:04 +0000 (16:26 -0700)]
introduce SIZE_MAX
ULONG_MAX is often used to check for integer overflow when calculating
allocation size. While ULONG_MAX happens to work on most systems, there
is no guarantee that `size_t' must be the same size as `long'.
This patch introduces SIZE_MAX, the maximum value of `size_t', to improve
portability and readability for allocation size validation.
Kautuk Consul [Thu, 31 May 2012 23:26:03 +0000 (16:26 -0700)]
um/kernel/trap.c: port OOM changes to handle_page_fault()
Commit d065bd810b6d ("mm: retry page fault when blocking on disk
transfer") and commit 37b23e0525d3 ("x86,mm: make pagefault killable")
introduced changes into the x86 pagefault handler for making the page
fault handler retryable as well as killable.
These changes reduce the mmap_sem hold time, which is crucial during OOM
killer invocation.
This allocation may be large. The code is probing to see if it will
succeed and if not, it falls back to vmalloc(). We should suppress any
page-allocation failure messages when the fallback happens.
Hannu Heikkinen [Tue, 29 May 2012 22:07:40 +0000 (15:07 -0700)]
drivers/rtc/rtc-tegra.c: clean up probe/remove routines
Use the devres managed resource functions in the probe routine. Also
affects the remove routine where the previously used free and release
functions are not needed.
The devm_* functions eliminate the need for manual resource releasing and
simplify error handling. Resources allocated by devm_* are freed
automatically on driver detach.
Remove RTT interrupt handling, since PIE mode interrupts are now better
emulated in generic code via an hrtimer we have no need for this, and
there is no codepath in the driver that enables these periodic interrupts
anyway.
Nikolaus Voss [Tue, 29 May 2012 22:07:39 +0000 (15:07 -0700)]
drivers/rtc/rtc-m41t93.c: don't let get_time() reset M41T93_FLAG_OF
If the rtc reports the time might be invalid due to oscillator failure,
M41T93_FLAG_OF flag must not be reset by get_time() as the read operation
doesn't make the time valid.
Without this patch, only the first get_time() reported an invalid time,
the second get_time() reported a valid time althought the reported time is
probably wrong due to oscillator failure.
Instead of resetting in get_time(), with this patch M41T93_FLAG_OF is
reset in set_time() when a valid time is to be written.
Wolfram Sang [Tue, 29 May 2012 22:07:38 +0000 (15:07 -0700)]
rtc: ds1307: add trickle charger support
Some DS13XX devices have "trickle chargers". Its configuration register
is at different locations, the setup is the same, though. Since the
configuration is board specific, introduce a platform_data to this driver.
Tested with a DS1339 on a custom board.
Alexander Stein [Tue, 29 May 2012 22:07:36 +0000 (15:07 -0700)]
rtc: add ioctl to get/clear battery low voltage status
Currently there is no generic way to get the RTC battery status within an
application. So add an ioctl to read the status bit. The idea is that
the bit is set once a low voltage is detected. It stays there until it is
reset using the RTC_VL_CLR ioctl.
Viresh Kumar [Tue, 29 May 2012 22:07:35 +0000 (15:07 -0700)]
rtc/spear: add Device Tree probing capability
SPEAr platforms now support DT and so must convert all drivers support DT.
This patch adds DT probing support for rtc and updates its documentation
too.
Stephen Boyd [Tue, 29 May 2012 22:07:34 +0000 (15:07 -0700)]
spinlock_debug: print kallsyms name for lock
When a spinlock warning is printed we usually get
BUG: spinlock bad magic on CPU#0, modprobe/111
lock: 0xdff09f38, .magic: 00000000, .owner: /0, .owner_cpu: 0
but it's nicer to print the symbol for the lock if we have it so that we
can avoid 'grep dff09f38 /proc/kallsyms' to find out which lock it was.
Use kallsyms to print the symbol name so we get something a bit easier to
read
BUG: spinlock bad magic on CPU#0, modprobe/112
lock: test_lock, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
If the lock is not in kallsyms %ps will fall back to printing the address
directly.
Stephen Boyd [Tue, 29 May 2012 22:07:33 +0000 (15:07 -0700)]
vsprintf: fix %ps on non symbols when using kallsyms
Using %ps in a printk format will sometimes fail silently and print the
empty string if the address passed in does not match a symbol that
kallsyms knows about. But using %pS will fall back to printing the full
address if kallsyms can't find the symbol. Make %ps act the same as %pS
by falling back to printing the address.
While we're here also make %ps print the module that a symbol comes from
so that it matches what %pS already does. Take this simple function for
example (in a module):
Andrew Morton [Tue, 29 May 2012 22:07:32 +0000 (15:07 -0700)]
lib/bitmap.c: fix documentation for scnprintf() functions
The code comments for bscnl_emit() and bitmap_scnlistprintf() are
describing snprintf() return semantics, but these functions use
scnprintf() return semantics. Fix that, and document the
bitmap_scnprintf() return value as well.
Uwe Kleine-König [Tue, 29 May 2012 22:07:31 +0000 (15:07 -0700)]
lib/test-kstrtox.c: mark const init data with __initconst instead of __initdata
As long as there is no other non-const variable marked __initdata in the
same compilation unit it doesn't hurt. If there were one however
compilation would fail with
error: $variablename causes a section type conflict
because a section containing const variables is marked read only and so
cannot contain non-const variables.
Chris Metcalf [Tue, 29 May 2012 22:07:31 +0000 (15:07 -0700)]
list_debug: WARN for adding something already in the list
We were bitten by this at one point and added an additional sanity test
for DEBUG_LIST. You can't validly add a list_head to a list where either
prev or next is the same as the thing you're adding.
Alexander Stein [Tue, 29 May 2012 22:07:30 +0000 (15:07 -0700)]
drivers/leds/leds-pca955x.c: fix race condition while setting brightness on several LEDs
When issuing the following command:
for I in 0 1 2 3 4 5 6 7; do
echo 0 > /sys/class/leds/pca955x\:${I}/brightness;
done
It is possible that all the pca955x_read_ls calls are done sequentially
before any pca955x_write_ls call is done. This updates the LS only to
the last LED update in its set.
Fix this by using a global lock for the pca995x device during
pca955x_led_work. Also used a struct for shared data betreen all LEDs.
Shuah Khan [Tue, 29 May 2012 22:07:30 +0000 (15:07 -0700)]
leds: add new transient trigger for one shot timer activation
The leds timer trigger does not currently have an interface to activate a
one shot timer. The current support allows for setting two timers, one
for specifying how long a state to be on, and the second for how long the
state to be off. The delay_on value specifies the time period an LED
should stay in on state, followed by a delay_off value that specifies how
long the LED should stay in off state. The on and off cycle repeats until
the trigger gets deactivated. There is no provision for one time
activation to implement features that require an on or off state to be
held just once and then stay in the original state forever.
Without one shot timer interface, user space can still use timer trigger
to set a timer to hold a state, however when user space application
crashes or goes away without deactivating the timer, the hardware will be
left in that state permanently.
As a specific example of this use-case, let's look at vibrate feature on
phones. Vibrate function on phones is implemented using PWM pins on SoC
or PMIC. There is a need to activate one shot timer to control the
vibrate feature, to prevent user space crashes leaving the phone in
vibrate mode permanently causing the battery to drain.
This trigger exports three properties, activate, state, and duration When
transient trigger is activated these properties are set to default values.
- duration allows setting timer value in msecs. The initial value is 0.
- activate allows activating and deactivating the timer specified by
duration as needed. The initial and default value is 0. This will allow
duration to be set after trigger activation.
- state allows user to specify a transient state to be held for the specified
duration.
Shuah Khan [Tue, 29 May 2012 22:07:28 +0000 (15:07 -0700)]
leds: change ledtrig-timer to use activated flag
Change existing timer trigger to use the new ->activated flag to set
activate successful status in activate routine and check it in deactivate
routine to do cleanup.
Shuah Khan [Tue, 29 May 2012 22:07:28 +0000 (15:07 -0700)]
leds: change existing triggers to use activated flag
Change existing triggers backlight, gpio, and heartbeat to use the new
->activated flag to set activate successful status in their activate
routines and check it in their deactivate routines to do cleanup.
Shuah Khan [Tue, 29 May 2012 22:07:27 +0000 (15:07 -0700)]
leds: add new field to led_classdev struct to save activation state
Add a new field to led_classdev to save activattion state after activate
routine is successful. This saved state is used in deactivate routine to
do cleanup such as removing device files, and free memory allocated during
activation. Currently trigger_data not being null is used for this
purpose.
Existing triggers will need changes to use this new field.
Thomas Meyer [Tue, 29 May 2012 22:07:27 +0000 (15:07 -0700)]
leds: Use kcalloc instead of kzalloc to allocate array
The advantage of kcalloc is that will prevent integer overflows which
could result from the multiplication of number of elements and size and it
is also a bit nicer to read.
The semantic patch that makes this change is available
in https://lkml.org/lkml/2011/11/25/107
drivers/leds/leds-lp5521.c: In function `lp5521_load_program':
drivers/leds/leds-lp5521.c:214:21: warning: `mode' may be used uninitialized in this function [-Wuninitialized]
drivers/leds/leds-lp5521.c: In function `lp5521_probe':
drivers/leds/leds-lp5521.c:788:5: warning: `buf' may be used uninitialized in this function [-Wuninitialized]
drivers/leds/leds-lp5521.c:740:6: warning: `ret' may be used uninitialized in this function [-Wuninitialized]
These are real problems if lp5521_read() returns an error. When that
happens we should handle it, instead of ignoring it or doing a bitwise
OR with all the other error codes and continuing.
Jingoo Han [Tue, 29 May 2012 22:07:18 +0000 (15:07 -0700)]
backlight: jornada720: use pr_err()/pr_info() instead of printk()
Use pr_err()/pr_info() instead of printk() to allow dynamic debugging.
The pr_fmt prefix for pr_ macros is used. Also fix checkpatch warnings as
below:
WARNING: Prefer pr_err(... to printk(KERN_ERR, ...
WARNING: Prefer pr_info(... to printk(KERN_INFO, ...
Jingoo Han [Tue, 29 May 2012 22:07:17 +0000 (15:07 -0700)]
backlight: cr_bllcd: use pr_err()/pr_info() instead of printk()
Use pr_err()/pr_info() instead of printk() to allow dynamic debugging.
The pr_fmt prefix for pr_ macros is used. Also fix checkpatch warnings as
below:
WARNING: printk() should include KERN_ facility level
WARNING: Prefer pr_err(... to printk(KERN_ERR, ...
Jingoo Han [Tue, 29 May 2012 22:07:16 +0000 (15:07 -0700)]
backlight: apple_bl: use pr_debug()/pr_err() instead of printk()
Use pr_debug()/pr_err() instead of printk() to allow dynamic debugging.
The pr_fmt prefix for pr_ macros is used. Also fix checkpatch warnings as
below:
WARNING: Prefer pr_debug(... to printk(KERN_DEBUG, ...
WARNING: Prefer pr_err(... to printk(KERN_ERR, ...
Jingoo Han [Tue, 29 May 2012 22:07:16 +0000 (15:07 -0700)]
backlight: use pr_warn() and pr_debug() instead of printk()
Use pr_warn() and pr_debug() instead of printk to allow dynamic debugging.
The pr_fmt prefix for pr_ macros is used. Also fix checkpatch warnings
as below:
WARNING: Prefer pr_warn(... to printk(KERN_WARNING, ...
drivers/video/backlight/apple_bl.c: include header for exported symbol prototypes
Include the header to pickup the exported symbol prototype.
Quiets the sparse warning:
warning: symbol 'apple_bl_register' was not declared. Should it be static?
warning: symbol 'apple_bl_unregister' was not declared. Should it be static?
Inki Dae [Tue, 29 May 2012 22:07:13 +0000 (15:07 -0700)]
lcd: add callbacks for early fb event blank support
This patchset adds early fb blank feature that a callback of lcd panel
driver is called prior to specific fb driver's one. In the case of
MIPI-DSI based video mode LCD Panel, for lcd power off, the power off
commands should be transferred to lcd panel with display and mipi-dsi
controller enabled because the commands is set to lcd panel at vsync porch
period. and in opposite case, the callback of fb driver should be called
prior to lcd panel driver's one because of same issue. Also if fb_blank
mode is changed to FB_BLANK_POWERDOWN then display controller would be
off(clock disable) but lcd panel would be still on. at this time, you
could see some issue like sparkling on lcd panel because video clock to be
delivered to ldi module of lcd panel was disabled. this issue could
occurs for all lcd panels.
The callback order is as the following:
at fb_blank function of fbmem.c
-> fb_notifier_call_chain(FB_EARLY_EVENT_BLANK)
-> lcd panel driver's early_set_power()
-> info->fbops->fb_blank()
-> spcefic fb driver's fb_blank()
-> fb_notifier_call_chain(FB_EVENT_BLANK)
-> lcd panel driver's set_power()
-> fb_notifier_call_chain(FB_R_EARLY_EVENT_BLANK) if
info->fops->fb_blank() was failed.
fb_notifier_call_chain(FB_R_EARLY_EVENT_BLANK) would be called to revert
the effects of previous FB_EARLY_EVENT_BLANK call. and note that if
early_set_power() of lcd_ops is NULL then early fb blank callback would be
ignored.
This patch:
Add early_set_power and r_early_set_power callbacks. early_set_power
callback is called prior to fb_blank() of fbmem.c and r_early_set_power
callback is called if fb_blank() was failed to revert the effects of the
early_set_power call of lcd panel driver.
Inki Dae [Tue, 29 May 2012 22:07:12 +0000 (15:07 -0700)]
fbdev: add events for early fb event support
Add FB_EARLY_EVENT_BLANK and FB_R_EARLY_EVENT_BLANK event mode supports.
first, fb_notifier_call_chain() is called with FB_EARLY_EVENT_BLANK and
fb_blank() of specific fb driver is called and then
fb_notifier_call_chain() is called with FB_EVENT_BLANK again at
fb_blank(). and if fb_blank() was failed then fb_nitifier_call_chain()
would be called with FB_R_EARLY_EVENT_BLANK to revert the previous
effects.
blacklight: remove redundant spi driver bus initialization
In ancient times it was necessary to manually initialize the bus field of
an spi_driver to spi_bus_type. These days this is done in
spi_driver_register() so we can drop the manual assignment.
The patch was generated using the following coccinelle semantic patch:
// <smpl>
@@
identifier _driver;
@@
struct spi_driver _driver = {
.driver = {
- .bus = &spi_bus_type,
},
};
// </smpl>
Glauber Costa [Tue, 29 May 2012 22:07:11 +0000 (15:07 -0700)]
memcg: decrement static keys at real destroy time
We call the destroy function when a cgroup starts to be removed, such as
by a rmdir event.
However, because of our reference counters, some objects are still
inflight. Right now, we are decrementing the static_keys at destroy()
time, meaning that if we get rid of the last static_key reference, some
objects will still have charges, but the code to properly uncharge them
won't be run.
This becomes a problem specially if it is ever enabled again, because now
new charges will be added to the staled charges making keeping it pretty
much impossible.
We just need to be careful with the static branch activation: since there
is no particular preferred order of their activation, we need to make sure
that we only start using it after all call sites are active. This is
achieved by having a per-memcg flag that is only updated after
static_key_slow_inc() returns. At this time, we are sure all sites are
active.
This is made per-memcg, not global, for a reason: it also has the effect
of making socket accounting more consistent. The first memcg to be
limited will trigger static_key() activation, therefore, accounting. But
all the others will then be accounted no matter what. After this patch,
only limited memcgs will have its sockets accounted.
Glauber Costa [Tue, 29 May 2012 22:07:10 +0000 (15:07 -0700)]
memcg: always free struct memcg through schedule_work()
Right now we free struct memcg with kfree right after a rcu grace period,
but defer it if we need to use vfree() to get rid of that memory area. We
do that by need, because we need vfree to be called in a process context.
This patch unifies this behavior, by ensuring that even kfree will happen
in a separate thread. The goal is to have a stable place to call the
upcoming jump label destruction function outside the realm of the
complicated and quite far-reaching cgroup lock (that can't be held when
holding either the cpu_hotplug.lock or jump_label_mutex)
Hugh Dickins [Tue, 29 May 2012 22:07:09 +0000 (15:07 -0700)]
mm/memcg: apply add/del_page to lruvec
Take lruvec further: pass it instead of zone to add_page_to_lru_list() and
del_page_from_lru_list(); and pagevec_lru_move_fn() pass lruvec down to
its target functions.
This cleanup eliminates a swathe of cruft in memcontrol.c, including
mem_cgroup_lru_add_list(), mem_cgroup_lru_del_list() and
mem_cgroup_lru_move_lists() - which never actually touched the lists.
In their place, mem_cgroup_page_lruvec() to decide the lruvec, previously
a side-effect of add, and mem_cgroup_update_lru_size() to maintain the
lru_size stats.
Whilst these are simplifications in their own right, the goal is to bring
the evaluation of lruvec next to the spin_locking of the lrus, in
preparation for a future patch.
Hugh Dickins [Tue, 29 May 2012 22:07:09 +0000 (15:07 -0700)]
mm: trivial cleanups in vmscan.c
Utter trivia in mm/vmscan.c, mostly just reducing the linecount slightly;
most exciting change being get_scan_count() calling vmscan_swappiness()
once instead of twice.
Hugh Dickins [Tue, 29 May 2012 22:07:08 +0000 (15:07 -0700)]
mm/memcg: get_lru_size not get_lruvec_size
Konstantin just introduced mem_cgroup_get_lruvec_size() and
get_lruvec_size(), I'm about to add mem_cgroup_update_lru_size(): but
we're dealing with the same thing, lru_size[lru]. We ought to agree on
the naming, and I do think lru_size is the more correct: so rename his
ones to get_lru_size().
Johannes Weiner [Tue, 29 May 2012 22:07:08 +0000 (15:07 -0700)]
mm: memcg: print statistics from live counters
Directly print statistics and event counters instead of going through an
intermediate accumulation stage into a separate array, which used to
require defining statistic items in more than one place.
Johannes Weiner [Tue, 29 May 2012 22:07:07 +0000 (15:07 -0700)]
mm: memcg: group swapped-out statistics counter logically
The counter of currently swapped out pages in a memcg (hierarchy) is
sitting amidst ever-increasing event counters. Move this item to the
other counters that reflect current state rather than history.
This technically breaks the kernel ABI, but hopefully nobody relies on the
order of items in memory.stat.
Johannes Weiner [Tue, 29 May 2012 22:07:06 +0000 (15:07 -0700)]
mm: memcg: print statistics directly to seq_file
Being able to use seq_printf() allows being smarter about statistics
name strings, which are currently listed twice, with the only difference
being a "total_" prefix on the hierarchical version.
MEM_CGROUP_STAT_DATA is a leftover from when item counters were living in
the same array as ever-increasing event counters. It's no longer needed,
use MEM_CGROUP_STAT_NSTATS to iterate over the stat array.
memcg: move charges to root cgroup if use_hierarchy=0
Presently, at removal of cgroup, ->pre_destroy() is called and moves
charges to the parent cgroup. A major reason for returning -EBUSY from
->pre_destroy() is that the 'moving' hits the parent's resource
limitation. It happens only when use_hierarchy=0.
Considering use_hierarchy=0, all cgroups should be flat. So, no one
cannot justify moving charges to parent...parent and children are in flat
configuration, not hierarchical.
This patch modifes the code to move charges to the root cgroup at
rmdir/force_empty if use_hierarchy==0. This will much simplify rmdir()
and reduce error in ->pre_destroy.
projects / linux.git / log