Linux-Block Archive on
 help / color / Atom feed
From: SeongJae Park <>
Cc: SeongJae Park <>,,,,,
Subject: [PATCH v6 0/2] xenbus/backend: Add a memory pressure handler callback
Date: Wed, 11 Dec 2019 04:24:25 +0000
Message-ID: <> (raw)

Granting pages consumes backend system memory.  In systems configured
with insufficient spare memory for those pages, it can cause a memory
pressure situation.  However, finding the optimal amount of the spare
memory is challenging for large systems having dynamic resource
utilization patterns.  Also, such a static configuration might lack

To mitigate such problems, this patchset adds a memory reclaim callback
to 'xenbus_driver' (patch 1) and use it to mitigate the problem in
'xen-blkback' (patch 2).  The third patch is a trivial cleanup of
variable names.

Base Version

This patch is based on v5.4.  A complete tree is also available at my
public git repo:

Patch History

Changes from v5
 - Wordsmith the commit messages (suggested by Roger Pau Monné)
 - Change the reclaim callback return type (suggested by Roger Pau Monné)
 - Change the type of the blkback squeeze duration variable
   (suggested by Roger Pau Monné)
 - Add a patch for removal of unnecessary static variable name prefixes
   (suggested by Roger Pau Monné)
 - Fix warnings

Changes from v4
 - Remove domain id parameter from the callback (suggested by Juergen Gross)
 - Rename xen-blkback module parameter (suggested by Stefan Nuernburger)

Changes from v3
 - Add general callback in xen_driver and use it (suggested by Juergen Gross)

Changes from v2
 - Rename the module parameter and variables for brevity
   (aggressive shrinking -> squeezing)

Changes from v1
 - Adjust the description to not use the term, `arbitrarily`
   (suggested by Paul Durrant)
 - Specify time unit of the duration in the parameter description,
   (suggested by Maximilian Heyne)
 - Change default aggressive shrinking duration from 1ms to 10ms
 - Merge two patches into one single patch

SeongJae Park (2):
  xenbus/backend: Add memory pressure handler callback
  xen/blkback: Squeeze page pools if a memory pressure is detected

 drivers/block/xen-blkback/blkback.c       | 23 +++++++++++++++--
 drivers/block/xen-blkback/common.h        |  1 +
 drivers/block/xen-blkback/xenbus.c        |  3 ++-
 drivers/xen/xenbus/xenbus_probe_backend.c | 31 +++++++++++++++++++++++
 include/xen/xenbus.h                      |  1 +
 5 files changed, 56 insertions(+), 3 deletions(-)


             reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-11  4:24 SeongJae Park [this message]
2019-12-11  4:26 ` [PATCH v6 1/3] xenbus/backend: Add " SeongJae Park
2019-12-11 11:46   ` Roger Pau Monné
2019-12-11 12:20     ` SeongJae Park
2019-12-11 12:30     ` Jürgen Groß
2019-12-11  4:27 ` [PATCH v6 2/3] xen/blkback: Squeeze page pools if a memory pressure is detected SeongJae Park
2019-12-11  4:27 ` [PATCH v6 3/3] xen/blkback: Remove unnecessary static variable name prefixes SeongJae Park
2019-12-11 11:56   ` Roger Pau Monné

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Block Archive on

Archives are clonable:
	git clone --mirror linux-block/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-block linux-block/ \
	public-inbox-index linux-block

Example config snippet for mirrors

Newsgroup available over NNTP:

AGPL code for this site: git clone