Create a new chapter about SMPS in the
driver API part of the mac80211 book and
populate it with the existing docs.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Add some existing documentation about station
handling to a new chapter about advanced APIs.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Publish the documentation for the interface
iteration functions in the right section of
the book.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Include the aggregation documentation in the
docbook, split up by public and internal docs.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Add an API chapter to the rate control part of
the mac80211 book and populate it with some
existing documentation.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
There isn't a clear TX documentation yet, so
put these into the misc section for now.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Put them along with their "regular" versions for
now, we should write more docs in the future.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Create a new chapter for the mac80211 workqueue
that contains the documentation written for it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Just include them in the list of functions,
there aren't any more detailed docs (yet).
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
* 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
i2c-i801: Add PCI idents for Patsburg 'IDF' SMBus controllers
i2c-i801: Handle multiple instances instead of keeping global state
i2c-i801: Add Intel Patsburg device ID
i2c: Drop unused I2C_CLASS_TV flags
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (70 commits)
[SCSI] pmcraid: add support for set timestamp command and other fixes
[SCSI] pmcraid: remove duplicate struct member
[SCSI] qla4xxx: Fix cmd check in qla4xxx_cmd_wait
[SCSI] megaraid_sas: Version and documentation update
[SCSI] megaraid_sas: Add three times Online controller reset
[SCSI] megaraid_sas: Add input parameter for max_sectors
[SCSI] megaraid_sas: support devices update flag
[SCSI] libosd: write/read_sg_kern API
[SCSI] libosd: Support for scatter gather write/read commands
[SCSI] libosd: Free resources in reverse order of allocation
[SCSI] libosd: Fix bug in attr_page handling
[SCSI] lpfc 8.3.18: Update lpfc driver version to 8.3.18
[SCSI] lpfc 8.3.18: Add new WQE support
[SCSI] lpfc 8.3.18: Fix critical errors
[SCSI] lpfc 8.3.18: Adapter Shutdown and Unregistration cleanup
[SCSI] lpfc 8.3.18: Add logic to detect last devloss timeout
[SCSI] lpfc 8.3.18: Add support of received ELS commands
[SCSI] lpfc 8.3.18: FC/FCoE Discovery fixes
[SCSI] ipr: add definitions for a new adapter
[SCSI] bfa: fix comments for c files
...
These are the extra 'Integrated Device Function' SMBus controllers found
on the Patsburg chipset. Mention the absence of slave mode support.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Add support for the Intel Patsburg PCH SMBus Controller.
Signed-off-by: Seth Heasley <seth.heasley@intel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This one was only used for a nasty hack in nfsd, which has recently
been removed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6: (39 commits)
Revert "namespace: add source file location exceptions"
Coccinelle: Add contextual message
Coccinelle: Fix documentation
Coccinelle: Find doubled arguments to boolean or bit operators.
Coccinelle: Find nested lock+irqsave functions that use the same flags variables.
namespace: add source file location exceptions
scripts/extract-ikconfig: add support for bzip2, lzma and lzo
kbuild: check return value of asprintf()
scripts/namespace.pl: improve to get more correct results
scripts/namespace.pl: some bug fixes
scripts/namespace.pl: update file exclusion list
scripts/namespace.pl: fix wrong source path
Coccinelle: Use the -no_show_diff option for org and report mode
Coccinelle: Add a new mode named 'chain'
Coccinelle: Use new comment format to explain kfree.cocci
Coccinelle: Improve user information with a new kind of comment
Coccinelle: Update documentation
MAINTAINERS: Coccinelle: Update email address
Documentation/kbuild: modules.txt cleanup
Documentation/kbuild: major edit of modules.txt sections 5-8
...
* 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6: (38 commits)
kbuild: convert `arch/tile' to the kconfig mainmenu upgrade
README: cite nconfig
Revert "kconfig: Temporarily disable dependency warnings"
kconfig: Use PATH_MAX instead of 128 for path buffer sizes.
kconfig: Fix realloc usage()
kconfig: Propagate const
kconfig: Don't go out from read config loop when you read new symbol
kconfig: fix menuconfig on debian lenny
kbuild: migrate all arch to the kconfig mainmenu upgrade
kconfig: expand file names
kconfig: use the file's name of sourced file
kconfig: constify file name
kconfig: don't emit warning upon rootmenu's prompt redefinition
kconfig: replace KERNELVERSION usage by the mainmenu's prompt
kconfig: delay gconf window initialization
kconfig: expand by default the rootmenu's prompt
kconfig: add a symbol string expansion helper
kconfig: regen parser
kconfig: implement the `mainmenu' directive
kconfig: allow PACKAGE to be defined on the compiler's command-line
...
Fix up trivial conflict in arch/mn10300/Kconfig
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
initramfs: Fix build break on symbol-prefixed archs
initramfs: fix initramfs size calculation
initramfs: generalize initramfs_data.xxx.S variants
scripts/kallsyms: Enable error messages while hush up unnecessary warnings
scripts/setlocalversion: update comment
kbuild: Use a single clean rule for kernel and external modules
kbuild: Do not run make clean in $(srctree)
scripts/mod/modpost.c: fix commentary accordingly to last changes
kbuild: Really don't clean bounds.h and asm-offsets.h
* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging: (68 commits)
hwmon: (it87) Add support for the IT8721F/IT8758E
hwmon: (it87) Move conversion functions
hwmon: Remove many EXPERIMENTAL flags
hwmon: (lm85) Add support for ADT7468 high-frequency PWM mode
hwmon: (lm85) Document the ADT7468 as supported
hwmon: (lm85) Fix ADT7468 frequency table
hwmon: I2C addresses are constant
Move ams driver to macintosh
hwmon: (pcf8591) Don't attempt to detect devices
hwmon: (pcf8591) Register as a hwmon device
hwmon: (w83795) Use standard attributes for chassis intrusion
hwmon: (w83795) Exclude fan control feature by default
hwmon: (w83795) Add myself as co-author and maintainer
hwmon: (w83795) More style cleanups
hwmon: (w83795) Fix LSB reading of voltage limits
hwmon: (w83795) Use dev_get_drvdata() where possible
hwmon: (w83795) Delay reading pwm config registers
hwmon: (w83795) Delay reading limit registers
hwmon: (w83795) Move register reads to dedicated functions
hwmon: (w83795) Pack similar register reads
...
* 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6: (27 commits)
x86: allocate space within a region top-down
x86: update iomem_resource end based on CPU physical address capabilities
x86/PCI: allocate space from the end of a region, not the beginning
PCI: allocate bus resources from the top down
resources: support allocating space within a region from the top down
resources: handle overflow when aligning start of available area
resources: ensure callback doesn't allocate outside available space
resources: factor out resource_clip() to simplify find_resource()
resources: add a default alignf to simplify find_resource()
x86/PCI: MMCONFIG: fix region end calculation
PCI: Add support for polling PME state on suspended legacy PCI devices
PCI: Export some PCI PM functionality
PCI: fix message typo
PCI: log vendor/device ID always
PCI: update Intel chipset names and defines
PCI: use new ccflags variable in Makefile
PCI: add PCI_MSIX_TABLE/PBA defines
PCI: add PCI vendor id for STmicroelectronics
x86/PCI: irq and pci_ids patch for Intel Patsburg DeviceIDs
PCI: OLPC: Only enable PCI configuration type override on XO-1
...
Add support for the IT8721F/IT8758E. These new chips differ from the
older IT87xxF chips in the following ways:
* ADC LSB is 12 mV instead of 16 mV.
* PWM values are 8-bit instead of 7-bit.
There are other minor changes we don't have to care about in the
driver.
Another change is that we will handle internal voltage scaling in the
driver instead of delegating the work to user-space.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The ADT7468 supports a high-frequency PWM output mode where all PWM
outputs are driven by a 22.5 kHz clock. Add support for this mode, and
document it, as it may surprise the user that setting one PWM output
frequency also affects the other PWM outputs.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Darrick J. Wong <djwong@us.ibm.com>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>
The PCF8591 can't be detected, don't even try. There are plenty of
other means to instantiate i2c devices these days.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Reviewed-by: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
I was wondering if that chip ever existed publicly... Apparently yes,
so add support for it.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Alexander Stein <alexander.stein@informatik.tu-chemnitz.de>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>
This merges the staging-next tree to Linus's tree and resolves
some conflicts that were present due to changes in other trees that were
affected by files here.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6: (505 commits)
[media] af9015: Fix max I2C message size when used with tda18271
[media] IR: initialize ir_raw_event in few more drivers
[media] Guard a divide in v4l1 compat layer
[media] imon: fix nomouse modprobe option
[media] imon: remove redundant change_protocol call
[media] imon: fix my egregious brown paper bag w/rdev/idev split
[media] cafe_ccic: Configure ov7670 correctly
[media] ov7670: allow configuration of image size, clock speed, and I/O method
[media] af9015: support for DigitalNow TinyTwin v3 [1f4d:9016]
[media] af9015: map DigitalNow TinyTwin v2 remote
[media] DigitalNow TinyTwin remote controller
[media] af9015: RC fixes and improvements
videodev2.h.xml: Update to reflect the latest changes at videodev2.h
[media] v4l: document new Bayer and monochrome pixel formats
[media] DocBook/v4l: Add missing formats used on gspca cpia1 and sn9c2028
[media] firedtv: add parameter to fake ca_system_ids in CA_INFO
[media] tm6000: fix a macro coding style issue
tm6000: Remove some ugly debug code
[media] Nova-S-Plus audio line input
[media] [RFC,1/1] V4L2: Use new CAP bits in existing RDS capable drivers
...
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc: (66 commits)
mmc: add new sdhci-pxa driver for Marvell SoCs
mmc: make number of mmcblk minors configurable
mmc_spi: Recover from CRC errors for r/w operation over SPI.
mmc: sdhci-pltfm: add -pltfm driver for imx35/51
mmc: sdhci-of-esdhc: factor out common stuff
mmc: sdhci_pltfm: pass more data on custom init call
mmc: sdhci: introduce get_ro private write-protect hook
mmc: sdhci-pltfm: move .h file into appropriate subdir
mmc: sdhci-pltfm: Add structure for host-specific data
mmc: fix cb710 kconfig dependency warning
mmc: cb710: remove debugging printk (info duplicated from mmc-core)
mmc: cb710: clear irq handler on init() error path
mmc: cb710: remove unnecessary msleep()
mmc: cb710: implement get_cd() callback
mmc: cb710: partially demystify clock selection
mmc: add a file to debugfs for changing host clock at runtime
mmc: sdhci: allow for eMMC 74 clock generation by controller
mmc: sdhci: highspeed: check for mmc as well as sd cards
mmc: sdhci: Add Moorestown device support
mmc: sdhci: Intel Medfield support
...
* 'viafb-next' of git://github.com/schandinat/linux-2.6: (29 commits)
viafb: add initial VX900 support
viafb: fix hardware acceleration for suspend & resume
viafb: make suspend and resume work (on all machines?)
viafb: restore display on resume
Minimal support for viafb suspend/resume
viafb: use proper register for colour when doing fill ops
viafb: add documentation for proc interface
viafb: rename output devices
viafb: add a mapping of supported output devices
viafb: set sync polarity for all output devices
viafb: add function to change sync polarity per device
viafb: reduce I2C timeout and delay
viafb: enable I2C for CRT
viafb: fix i2c_transfer error handling
viafb: vt1636 cleanup
viafb: introduce per output device power management
viafb: limit LCD code impact
viafb: add interface for output device configuration
viafb: merge the remaining output path with enable functions
viafb: use new device routing
...
* akpm-incoming-2: (139 commits)
epoll: make epoll_wait() use the hrtimer range feature
select: rename estimate_accuracy() to select_estimate_accuracy()
Remove duplicate includes from many files
ramoops: use the platform data structure instead of module params
kernel/resource.c: handle reinsertion of an already-inserted resource
kfifo: fix kfifo_alloc() to return a signed int value
w1: don't allow arbitrary users to remove w1 devices
alpha: remove dma64_addr_t usage
mips: remove dma64_addr_t usage
sparc: remove dma64_addr_t usage
fuse: use release_pages()
taskstats: use real microsecond granularity for CPU times
taskstats: split fill_pid function
taskstats: separate taskstats commands
delayacct: align to 8 byte boundary on 64-bit systems
delay-accounting: reimplement -c for getdelays.c to report information on a target command
namespaces Kconfig: move namespace menu location after the cgroup
namespaces Kconfig: remove the cgroup device whitelist experimental tag
namespaces Kconfig: remove pointless cgroup dependency
namespaces Kconfig: make namespace a submenu
...
When the lazy_itable_init extended option is passed to mke2fs, it
considerably speeds up filesystem creation because inode tables are
not zeroed out. The fact that parts of the inode table are
uninitialized is not a problem so long as the block group descriptors,
which contain information regarding how much of the inode table has
been initialized, has not been corrupted However, if the block group
checksums are not valid, e2fsck must scan the entire inode table, and
the the old, uninitialized data could potentially cause e2fsck to
report false problems.
Hence, it is important for the inode tables to be initialized as soon
as possble. This commit adds this feature so that mke2fs can safely
use the lazy inode table initialization feature to speed up formatting
file systems.
This is done via a new new kernel thread called ext4lazyinit, which is
created on demand and destroyed, when it is no longer needed. There
is only one thread for all ext4 filesystems in the system. When the
first filesystem with inititable mount option is mounted, ext4lazyinit
thread is created, then the filesystem can register its request in the
request list.
This thread then walks through the list of requests picking up
scheduled requests and invoking ext4_init_inode_table(). Next schedule
time for the request is computed by multiplying the time it took to
zero out last inode table with wait multiplier, which can be set with
the (init_itable=n) mount option (default is 10). We are doing
this so we do not take the whole I/O bandwidth. When the thread is no
longer necessary (request list is empty) it frees the appropriate
structures and exits (and can be created later later by another
filesystem).
We do not disturb regular inode allocations in any way, it just do not
care whether the inode table is, or is not zeroed. But when zeroing, we
have to skip used inodes, obviously. Also we should prevent new inode
allocations from the group, while zeroing is on the way. For that we
take write alloc_sem lock in ext4_init_inode_table() and read alloc_sem
in the ext4_claim_inode, so when we are unlucky and allocator hits the
group which is currently being zeroed, it just has to wait.
This can be suppresed using the mount option no_init_itable.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Task delay-accounting was identified as one means of determining how long
a process spends in congestion_wait() without adding new statistics. For
example, if the workload should not be doing IO, delay-accounting could
reveal how long it was spending in unexpected IO or delays.
Unfortunately, on closer examination it was clear that getdelays does not
act as documented.
Commit a3baf649 ("per-task-delay-accounting: documentation") added
Documentation/accounting/getdelays.c with a -c switch that was documented
to fork/exec a child and report statistics on it but for reasons that are
unclear to me, commit 9e06d3f9 deleted support for this switch but did not
update the documentation. It might be an oversight or it might be because
the control flow of the program meant that accounting information would be
printed once early in the lifetime of the program making it of limited
use.
This patch reimplements -c for getdelays.c to act as documented. Unlike
the original version, it waits until the command completes before printing
any information on it. An example of it being used looks like
$ ./getdelays -d -c find /home/mel -name mel
print delayacct stats ON
/home/mel
/home/mel/.notes-wine/drive_c/windows/profiles/mel
/home/mel/.wine/drive_c/windows/profiles/mel
/home/mel/git-configs/dot.kde/share/apps/konqueror/home/mel
PID 5923
CPU count real total virtual total delay total
42779 5051232096 5164722692 564207988
IO count delay total
41727 97804147758
SWAP count delay total
0 0
RECLAIM count delay total
0 0
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Export the number of anonymous pages in a mapping via smaps.
Even the private pages in a mapping backed by a file, would be marked as
anonymous, when they are modified. Export this information to user-space via
smaps.
Exporting this count will help gdb to make a better decision on which
areas need to be dumped in its coredump; and should be useful to others
studying the memory usage of a process.
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The ns_cgroup will be removed very soon. Let's warn, for this version,
ns_cgroup is deprecated.
Make ns_cgroup and clone_children exclusive. If the clone_children is set
and the ns_cgroup is mounted, let's fail with EINVAL when the ns_cgroup
subsys is created (a printk will help the user to understand why the
creation fails).
Update the feature remove schedule file with the deprecated ns_cgroup.
Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The ns_cgroup is a control group interacting with the namespaces. When a
new namespace is created, a corresponding cgroup is automatically created
too. The cgroup name is the pid of the process who did 'unshare' or the
child of 'clone'.
This cgroup is tied with the namespace because it prevents a process to
escape the control group and use the post_clone callback, so the child
cgroup inherits the values of the parent cgroup.
Unfortunately, the more we use this cgroup and the more we are facing
problems with it:
(1) when a process unshares, the cgroup name may conflict with a
previous cgroup with the same pid, so unshare or clone return -EEXIST
(2) the cgroup creation is out of control because there may have an
application creating several namespaces where the system will
automatically create several cgroups in his back and let them on the
cgroupfs (eg. a vrf based on the network namespace).
(3) the mix of (1) and (2) force an administrator to regularly check
and clean these cgroups.
This patchset removes the ns_cgroup by adding a new flag to the cgroup and
the cgroupfs mount option. It enables the copy of the parent cgroup when
a child cgroup is created. We can then safely remove the ns_cgroup as
this flag brings a compatibility. We have now to manually create and add
the task to a cgroup, which is consistent with the cgroup framework.
This patch:
Sent as an answer to a previous thread around the ns_cgroup.
https://lists.linux-foundation.org/pipermail/containers/2009-June/018627.html
It adds a control file 'clone_children' for a cgroup. This control file
is a boolean specifying if the child cgroup should be a clone of the
parent cgroup or not. The default value is 'false'.
This flag makes the child cgroup to call the post_clone callback of all
the subsystem, if it is available.
At present, the cpuset is the only one which had implemented the
post_clone callback.
The option can be set at mount time by specifying the 'clone_children'
mount option.
Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Paul Menage <menage@google.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jamal Hadi Salim <hadi@cyberus.ca>
Cc: Matt Helsley <matthltc@us.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When dirty_ratio or dirty_bytes is written the other parameter is disabled
and set to 0 (in dirty_bytes_handler() / dirty_ratio_handler()).
We do the same for dirty_background_ratio and dirty_background_bytes.
However, in the sysctl documentation, we say that the counterpart becomes
a function of the old value, that is not correct.
Clarify the documentation reporting the actual behaviour.
Reviewed-by: Greg Thelen <gthelen@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrea Righi <arighi@develer.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A file used as example has been moved elsewhere.
Update the documentation accordingly
Signed-off-by: Nicolas Palix <npalix.work@gmail.com>
Reported-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Michal Marek <mmarek@suse.cz>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (52 commits)
split invalidate_inodes()
fs: skip I_FREEING inodes in writeback_sb_inodes
fs: fold invalidate_list into invalidate_inodes
fs: do not drop inode_lock in dispose_list
fs: inode split IO and LRU lists
fs: switch bdev inode bdi's correctly
fs: fix buffer invalidation in invalidate_list
fsnotify: use dget_parent
smbfs: use dget_parent
exportfs: use dget_parent
fs: use RCU read side protection in d_validate
fs: clean up dentry lru modification
fs: split __shrink_dcache_sb
fs: improve DCACHE_REFERENCED usage
fs: use percpu counter for nr_dentry and nr_dentry_unused
fs: simplify __d_free
fs: take dcache_lock inside __d_path
fs: do not assign default i_ino in new_inode
fs: introduce a per-cpu last_ino allocator
new helper: ihold()
...
