[Xen-devel] [PATCH v2 0/7] xenstore: support reading directory with many children

[Juergen Gross <jgross@xxxxxxxx>]

Reading the children list of a xenstore node with the length of that
list exceeding 4096 bytes is currently not possible. This can be a
problem for a large host with a huge number of domains as Xen tools
will no longer by capable to scan some directories of xenstore (e.g.
/local/domain).

This patch series adds a new xs wire command to read a directory
in multiple chunks. libxenstore is modified in a compatible way to
show an unmodified result in case xenstored doesn't support the new
command.

The patch set has been verified to work by using the following shell script:

xenstore-write /test "test"

for i in `seq 100 500`
do
    xenstore-write /test/entry_with_very_long_name_$i $i
done

xenstore-ls
xenstore-rm /test

Xenstore has been verified to work by starting multiple domain types.
Especially HVM with qemu-stubdom has been tested as this configuration
seems to be rather sensible to concurrent transactions.

Changes in V2:
- complete rework as suggested by Jan Beulich: don't use transactions
  for consistency, but a per-node generation count
- fix a (minor?) problem in transaction code regarding watches (patch 1)

Juergen Gross (7):
  xenstore: fix add_change_node()
  xenstore: modify add_change_node() parameter types
  xenstore: call add_change_node() directly when writing node
  xenstore: use common tdb record header in xenstore
  xenstore: add per-node generation counter
  xenstore: add support for reading directory with many children
  xenstore: support XS_DIRECTORY_PART in libxenstore

 tools/xenstore/include/xenstore_lib.h  |   9 +++
 tools/xenstore/xenstored_core.c        | 120 ++++++++++++++++++++++++++-------
 tools/xenstore/xenstored_core.h        |   3 +
 tools/xenstore/xenstored_transaction.c |  27 +++++---
 tools/xenstore/xenstored_transaction.h |   4 +-
 tools/xenstore/xs.c                    |  80 +++++++++++++++++++---
 tools/xenstore/xs_tdb_dump.c           |  11 +--
 xen/include/public/io/xs_wire.h        |   1 +
 8 files changed, 205 insertions(+), 50 deletions(-)

-- 
2.6.6


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel