linux-stable.git/tools/cgroup, branch v5.7.7

iocost_monitor: drop string wrap around numbers when outputting json

2020-06-22T07:32:36+00:00

[ Upstream commit 21f3cfeab304fc07b90d93d98d4d2f62110fe6b2 ]

Wrapping numbers in strings is used by some to work around bit-width issues in
some enviroments. The problem isn't innate to json and the workaround seems to
cause more integration problems than help. Let's drop the string wrapping.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

iocost: protect iocg->abs_vdebt with iocg->waitq.lock

2020-05-05T15:23:18+00:00

abs_vdebt is an atomic_64 which tracks how much over budget a given cgroup
is and controls the activation of use_delay mechanism. Once a cgroup goes
over budget from forced IOs, it has to pay it back with its future budget.
The progress guarantee on debt paying comes from the iocg being active -
active iocgs are processed by the periodic timer, which ensures that as time
passes the debts dissipate and the iocg returns to normal operation.

However, both iocg activation and vdebt handling are asynchronous and a
sequence like the following may happen.

1. The iocg is in the process of being deactivated by the periodic timer.

2. A bio enters ioc_rqos_throttle(), calls iocg_activate() which returns
   without anything because it still sees that the iocg is already active.

3. The iocg is deactivated.

4. The bio from #2 is over budget but needs to be forced. It increases
   abs_vdebt and goes over the threshold and enables use_delay.

5. IO control is enabled for the iocg's subtree and now IOs are attributed
   to the descendant cgroups and the iocg itself no longer issues IOs.

This leaves the iocg with stuck abs_vdebt - it has debt but inactive and no
further IOs which can activate it. This can end up unduly punishing all the
descendants cgroups.

The usual throttling path has the same issue - the iocg must be active while
throttled to ensure that future event will wake it up - and solves the
problem by synchronizing the throttling path with a spinlock. abs_vdebt
handling is another form of overage handling and shares a lot of
characteristics including the fact that it isn't in the hottest path.

This patch fixes the above and other possible races by strictly
synchronizing abs_vdebt and use_delay handling with iocg->waitq.lock.

Signed-off-by: Tejun Heo 
Reported-by: Vlad Dmitriev 
Cc: stable@vger.kernel.org # v5.4+
Fixes: e1518f63f246 ("blk-iocost: Don't let merges push vtime into the future")
Signed-off-by: Jens Axboe

.gitignore: add SPDX License Identifier

2020-03-25T10:50:48+00:00

Add SPDX License Identifier to all .gitignore files.

Signed-off-by: Masahiro Yamada 
Signed-off-by: Greg Kroah-Hartman

iocost: Fix iocost_monitor.py due to helper type mismatch

2020-01-17T19:54:35+00:00

iocost_monitor.py broke with recent versions of drgn due to helper
being stricter about types.  Fix it so that it uses the correct type.

Signed-off-by: Tejun Heo 
Suggested-by: Omar Sandoval

iocost_monitor: Report debt

2019-09-10T18:31:39+00:00

Report debt and rename del_ms row to delay for consistency.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

iocost_monitor: Report more info with higher accuracy

2019-09-10T18:31:39+00:00

When outputting json:

* Don't truncate numbers.

* Report address of iocg to ease drilling down further.

When outputting table:

* Use math.ceil() for delay_ms so that small delays don't read as 0.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

iocost_monitor: Always use strings for json values

2019-09-10T18:31:39+00:00

Json has limited accuracy for numbers and can silently truncate 64bit
values, which can be extremely confusing.  Let's consistently use
string encapsulated values for json output.

While at it, convert an unnecesary f-string to str().

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

blkcg: add tools/cgroup/iocost_coef_gen.py

2019-08-29T03:17:17+00:00

Add a script which can be used to generate device-specific iocost
linear model coefficients.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

blkcg: add tools/cgroup/iocost_monitor.py

2019-08-29T03:17:14+00:00

Instead of mucking with debugfs and ->pd_stat(), add drgn based
monitoring script.

Signed-off-by: Tejun Heo 
Cc: Omar Sandoval 
Signed-off-by: Jens Axboe

tools: fix cross-compile var clobbering

2018-02-21T23:35:42+00:00

Currently a number of Makefiles break when used with toolchains that
pass extra flags in CC and other cross-compile related variables (such
as --sysroot).

Thus we get this error when we use a toolchain that puts --sysroot in
the CC var:

  ~/src/linux/tools$ make iio
  [snip]
  iio_event_monitor.c:18:10: fatal error: unistd.h: No such file or directory
    #include 
             ^~~~~~~~~~

This occurs because we clobber several env vars related to
cross-compiling with lines like this:

  CC = $(CROSS_COMPILE)gcc

Although this will point to a valid cross-compiler, we lose any extra
flags that might exist in the CC variable, which can break toolchains
that rely on them (for example, those that use --sysroot).

This easily shows up using a Yocto SDK:

  $ . [snip]/sdk/environment-setup-cortexa8hf-neon-poky-linux-gnueabi

  $ echo $CC
  arm-poky-linux-gnueabi-gcc -march=armv7-a -mfpu=neon -mfloat-abi=hard
  -mcpu=cortex-a8
  --sysroot=[snip]/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi

  $ echo $CROSS_COMPILE
  arm-poky-linux-gnueabi-

  $ echo ${CROSS_COMPILE}gcc
  krm-poky-linux-gnueabi-gcc

Although arm-poky-linux-gnueabi-gcc is a cross-compiler, we've lost the
--sysroot and other flags that enable us to find the right libraries to
link against, so we can't find unistd.h and other libraries and headers.
Normally with the --sysroot flag we would find unistd.h in the sdk
directory in the sysroot:

  $ find [snip]/sdk/sysroots -path '*/usr/include/unistd.h'
  [snip]/sdk/sysroots/cortexa8hf-neon-poky-linux-gnueabi/usr/include/unistd.h

The perf Makefile adds CC = $(CROSS_COMPILE)gcc if and only if CC is not
already set, and it compiles correctly with the above toolchain.

So, generalize the logic that perf uses in the common Makefile and
remove the manual CC = $(CROSS_COMPILE)gcc lines from each Makefile.

Note that this patch does not fix cross-compile for all the tools (some
have other bugs), but it does fix it for all except usb and acpi, which
still have other unrelated issues.

I tested both with and without the patch on native and cross-build and
there appear to be no regressions.

Link: http://lkml.kernel.org/r/20180107214028.23771-1-martin@martingkelly.com
Signed-off-by: Martin Kelly 
Acked-by: Mark Brown 
Cc: Tejun Heo 
Cc: Li Zefan 
Cc: Johannes Weiner 
Cc: Linus Walleij 
Cc: "K. Y. Srinivasan" 
Cc: Haiyang Zhang 
Cc: Stephen Hemminger 
Cc: Jonathan Cameron 
Cc: Pali Rohar 
Cc: Richard Purdie 
Cc: Jacek Anaszewski 
Cc: Pavel Machek 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Arnaldo Carvalho de Melo 
Cc: Robert Moore 
Cc: Lv Zheng 
Cc: "Rafael J. Wysocki" 
Cc: Greg Kroah-Hartman 
Cc: Valentina Manea 
Cc: Shuah Khan 
Cc: Mario Limonciello 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds