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* [PATCHSET -mm] bitmap, cpumask, nodemask: implement pr_cont functions and use di"
@ 2014-12-10 15:52 Tejun Heo
  2014-12-10 15:52 ` [PATCH 01/12] bitmap: restructure bitmap_sn[list]printf() Tejun Heo
                   ` (12 more replies)
  0 siblings, 13 replies; 23+ messages in thread
From: Tejun Heo @ 2014-12-10 15:52 UTC (permalink / raw)
  To: akpm; +Cc: linux-kernel

Hello,

bitmap implements two variants of scnprintf functions to format a
bitmap into a string and cpumask and nodemask wrap them to provide
equivalent interfaces.  The scnprintf family of functions require a
string buffer as an output target which complicates code paths which
just want to print out the mask through printk for informational or
debug purposes as they have to worry about how large the buffer should
be and whether it's too large to allocate on stack.

Neither cpumask or nodemask provides a guildeline on how large the
target buffer should be forcing users come up with their own solutions
- some allocate an arbitrarily sized buffer which is small enough to
allocate on stack but may be too short in corner cases, other come up
with a custom upper limit calculation considering the output format,
some allocate the buffer dynamically while one resorted to using lock
to synchronize access to a static buffer.

This is an artificial problem which is being solved repeatedly for no
benefit.  In a lot of cases, the output area already exists and can be
targeted directly making the intermediate buffer unnecessary.  This
patchset implement pr_cont variants of the formatting functions and
convert the scnprintf output function users to use them or seq_*()
functions to directly target the output area and remove the
intermediate buffers where possible.

This patchset contains the following 12 patches.

 0001-bitmap-restructure-bitmap_sn-list-printf.patch
 0002-bitmap-cpumask-nodemask-implement-pr_cont-variants-o.patch
 0003-mips-use-cpu-node-mask-pr_cont-and-seq-output-functi.patch
 0004-powerpc-use-cpu-node-mask-pr_cont-and-seq-output-fun.patch
 0005-tile-use-cpu-node-mask-pr_cont-and-seq-output-functi.patch
 0006-x86-use-cpu-node-mask-pr_cont-and-seq-output-functio.patch
 0007-xtensa-use-cpu-node-mask-pr_cont-and-seq-output-func.patch
 0008-cpuset-use-cpu-node-mask-pr_cont-and-seq-output-func.patch
 0009-rcu-use-cpu-node-mask-pr_cont-and-seq-output-functio.patch
 0010-sched-use-cpu-node-mask-pr_cont-and-seq-output-funct.patch
 0011-timer-use-cpu-node-mask-pr_cont-and-seq-output-funct.patch
 0012-percpu-use-cpu-node-mask-pr_cont-and-seq-output-func.patch

The first two patches implement the pr_cont variants of the formatting
functions.  The rest convert the existing users to pr_cont and seq
functions subsystem-by-subsystem.  It'd be the easiest to route all
through -mm but the conversion patches can go through individual
subsystem trees afterwards if necessary.

While there's ~70 line increase in LOC, the increase is from the
restructuring of bitmap output functions and addition of inline
interface functions along with comments and things get simplified /
more robust on the user side and future users won't have to try to
solve the same fruitless problem over and over again.

The patchset is based on top of -mm as of Dec 9, 2014 and also
available in the following git branch.

 git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc.git review-bitmap-pr_cont

 arch/mips/netlogic/common/smp.c     |   11 +-
 arch/powerpc/sysdev/xics/ics-opal.c |    7 -
 arch/powerpc/sysdev/xics/ics-rtas.c |    8 -
 arch/tile/kernel/hardwall.c         |    6 -
 arch/tile/kernel/proc.c             |    6 -
 arch/tile/kernel/setup.c            |   12 +-
 arch/tile/mm/homecache.c            |   14 +--
 arch/tile/mm/init.c                 |   12 +-
 arch/x86/mm/numa.c                  |    9 --
 arch/x86/platform/uv/uv_nmi.c       |   27 ++----
 arch/xtensa/kernel/setup.c          |   10 --
 drivers/net/ethernet/tile/tilegx.c  |    6 -
 drivers/net/ethernet/tile/tilepro.c |    6 -
 include/linux/bitmap.h              |    4 
 include/linux/cpumask.h             |   18 ++++
 include/linux/nodemask.h            |   16 +++
 kernel/cpuset.c                     |   13 ---
 kernel/rcu/tree_plugin.h            |    6 -
 kernel/sched/core.c                 |   11 +-
 kernel/sched/stats.c                |   11 --
 kernel/time/tick-sched.c            |   12 --
 lib/bitmap.c                        |  148 ++++++++++++++++++++++++++----------
 mm/percpu.c                         |    7 -
 23 files changed, 224 insertions(+), 156 deletions(-)

Thanks.

--
tejun

^ permalink raw reply	[flat|nested] 23+ messages in thread

end of thread, other threads:[~2015-01-12 14:00 UTC | newest]

Thread overview: 23+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-12-10 15:52 [PATCHSET -mm] bitmap, cpumask, nodemask: implement pr_cont functions and use di" Tejun Heo
2014-12-10 15:52 ` [PATCH 01/12] bitmap: restructure bitmap_sn[list]printf() Tejun Heo
2014-12-10 15:52 ` [PATCH 02/12] bitmap, cpumask, nodemask: implement pr_cont variants of formatting functions Tejun Heo
2014-12-10 15:52 ` [PATCH 03/12] mips: use {cpu|node}mask pr_cont and seq output functions Tejun Heo
2014-12-10 15:52 ` [PATCH 04/12] powerpc: " Tejun Heo
2014-12-10 15:52 ` [PATCH 05/12] tile: " Tejun Heo
2014-12-15 16:20   ` Chris Metcalf
2014-12-10 15:52 ` [PATCH 06/12] x86: " Tejun Heo
2014-12-10 15:52 ` [PATCH 07/12] xtensa: " Tejun Heo
2014-12-10 18:38   ` Max Filippov
2014-12-10 15:52 ` [PATCH 08/12] cpuset: " Tejun Heo
2014-12-10 15:52 ` [PATCH 09/12] rcu: " Tejun Heo
2014-12-10 16:29   ` Paul E. McKenney
2014-12-10 15:52 ` [PATCH 10/12] sched: " Tejun Heo
2014-12-15 10:39   ` Peter Zijlstra
2015-01-12 13:31     ` Tejun Heo
2015-01-12 13:50       ` Peter Zijlstra
2015-01-12 13:55         ` Tejun Heo
2015-01-12 14:00           ` Tejun Heo
2014-12-10 15:52 ` [PATCH 11/12] timer: " Tejun Heo
2014-12-10 15:52 ` [PATCH 12/12] percpu: " Tejun Heo
2014-12-10 21:49 ` [PATCHSET -mm] bitmap, cpumask, nodemask: implement pr_cont functions and use di" Andrew Morton
2014-12-10 22:12   ` Tejun Heo

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