This is a further revision of the basic hugectl support incorporating
further feedback, and a number of other cleanups which came out of the
work to address them. This is based on the current master which includes
my cleanup stack 'hugectl cleanups II (V1)'. This is probababally about
ready for merging, after the v2.0 release.
It might make sense to start building a branch with all these new things so
we can test against it, like a testing branch.
Changelog:
V6:
- fix miss un-merge of the library suppression
V5:
- added in collected acks
- option --library -> --library-path
- library path support for both single directories and library prefix
- split out the library fallback support
V4:
- separate out cleanups into their own series
- all new option help specification
- option --explain becomes --dry-run
- option --no-library becomes --library-use-path
V3:
- abstract out the verbosity levels
- cleanup and abstract long option values
- always indicate environmental variables as they are set
- library path defaults to set, and may be suppressed
- adds --explain to expose configuration
V2:
- incorporate community feedback
====
I have been looking at adding basic functionality to hugectl. Following
on from my cleanup series this patch set adds basic remap functionality
to hugectl. The short version of the story is that it adds options to
request backing of the text, data, bss, and heap as first class options
and simplifies preload handling, library path specification, and exposes
configuration on request.
The main driver for hugectl is to simplify the use of hugepages as
exported through the libhugetlbfs library. Specifically we should be
trying to do what the user means where possible. This patch set brings
basic support for requesting remap and/or backing of the various elements
program elements supported by libhugetlbfs. This includes the request
of remap of the various program segments, as well as requesting the heap
(malloc space) be backed. Where appropriate it tries to configure preload
of the library.
When considering the current configuration the clearest anomoly seems to be
the difference in handling of normal program segments and malloc. From a
user point of view hugepages are something which I use for something,
to back something. Backing my text with hugepages or my malloc space
with hugepages are the same thing. That is I have a bunch of things,
text, data, bss, malloc all of which I may wish or not wish to back
with hugepages. The underlying implementation differences are hidden by
exposing each as its own option, all at the same level.
hugectl --text
hugectl --data --bss
hugectl --heap
hugectl --stack (for illustrative purposes only)
hugectl --disable
Note that while each thing is separately specified, in reality only certain
combinations are valid. Where the user specifies a bad combination it
is "widened" to a valid combination which includes their request and a
warning is emitted. This helps to get the user going and is part of the
DWIM approach.
Preloading is a little tricky as it is only useful where the binary
is not-prelinked and only there is we are only asking for the heap to
be backed. But in that combination we can always preload safely which should
remove the need to every conciously request it. In case it is a problem
we allow it to be suppressed via --no-preload.
Finally it is helpful to be able to see the options in use for any
particular combination of arguments, expose this via --explain.
This stack consists of 6 patches:
hugectl: honour the hugetlb verbosity/debug flags -- reads the standard
libhugetlbfs verbosity and debug control flags and supplies compatible
error and warning routines,
hugectl: add remap support via --text, --data, --bss, and --disable --
which adds basic remap support via separated options,
hugectl: add backing of the heap via --heap -- which adds heap remapping
via --heap,
hugectl: add support for preload -- where preload is appropriate request
preloading of the library,
hugectl: explain the hugetlb configuration selected via --explain --
which allow exposure of the variable settings for a specific command line.
hugectl: add support for requesting which library to use -- providing
an override for the normal library path allowing clean execution in
non-standard installs, and
hugectl: allow suppression of the library path -- allow all library path
modification to be suppressed.
Thanks for Nish, Adam, Mel, David and Andrew for feedback during this
process.
Comments?
-apw
Andy Whitcroft (7):
hugectl: honour the hugetlb verbosity/debug flags
hugectl: add remap support via --text, --data, --bss, and --disable
hugectl: add backing of the heap via --heap
hugectl: add support for preload
hugectl: add a --dry-run option to dump what would be done
hugectl: add support for requesting which library to use
hugectl: allow suppression of the library path
Makefile | 9 ++-
hugectl.c | 238 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 243 insertions(+), 4 deletions(-)
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