From: SeongJae Park <sjpark@amazon.com>
To: <jgross@suse.com>, <axboe@kernel.dk>, <konrad.wilk@oracle.com>,
<roger.pau@citrix.com>
Cc: SeongJae Park <sjpark@amazon.com>, <pdurrant@amazon.com>,
<sj38.park@gmail.com>, <xen-devel@lists.xenproject.org>,
<linux-block@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH v12 0/5] xenbus/backend: Add memory pressure handler callback
Date: Wed, 18 Dec 2019 11:42:27 +0100 [thread overview]
Message-ID: <20191218104232.9606-1-sjpark@amazon.com> (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
flexibility.
To mitigate such problems, this patchset adds a memory reclaim callback
to 'xenbus_driver' (patch 1) and then introduce a lock for race
condition avoidance (patch 2). After that, patch 3 applies the callback
mechanism to mitigate the problem in 'xen-blkback'. The fourth and
fifth patches are trivial cleanups; those fix nits we found during the
development of this patchset.
Note that patch 1, 4, and 5 are not changed since v9.
Base Version
------------
This patch is based on v5.4. A complete tree is also available at my
public git repo:
https://github.com/sjp38/linux/tree/patches/blkback/buffer_squeeze/v12
Patch History
-------------
Changes from v11
(https://lore.kernel.org/xen-devel/20191217160748.693-2-sjpark@amazon.com/)
- Fix wrong trylock use (reported by Juergen)
- Merge patch 3 and 4 (suggested by Juergen)
- Update test result
Changes from v10
(https://lore.kernel.org/xen-devel/20191216124527.30306-1-sjpark@amazon.com/)
- Fix race condition (reported by SeongJae, suggested by Juergen)
Changes from v9
(https://lore.kernel.org/xen-devel/20191213153546.17425-1-sjpark@amazon.de/)
- Add 'Reviewed-by' and 'Acked-by' from Roger Pau Monné
- Update the commit message for overhead test of the 2nd path
Changes from v8
(https://lore.kernel.org/xen-devel/20191213130211.24011-1-sjpark@amazon.de/)
- Drop 'Reviewed-by: Juergen' from the second patch
(suggested by Roger Pau Monné)
- Update contact of the new module param to SeongJae Park
<sjpark@amazon.de>
(suggested by Roger Pau Monné)
- Wordsmith the description of the parameter
(suggested by Roger Pau Monné)
- Fix dumb bugs
(suggested by Roger Pau Monné)
- Move module param definition to xenbus.c and reduce the number of
lines for this change
(suggested by Roger Pau Monné)
- Add a comment for the new callback, reclaim_memory, as other
callbacks also have
- Add another trivial cleanup of xenbus.c file (4th patch)
Changes from v7
(https://lore.kernel.org/xen-devel/20191211181016.14366-1-sjpark@amazon.de/)
- Update sysfs-driver-xen-blkback for new parameter
(suggested by Roger Pau Monné)
- Use per-xen_blkif buffer_squeeze_end instead of global variable
(suggested by Roger Pau Monné)
Changes from v6
(https://lore.kernel.org/linux-block/20191211042428.5961-1-sjpark@amazon.de/)
- Remove more unnecessary prefixes (suggested by Roger Pau Monné)
- Constify a variable (suggested by Roger Pau Monné)
- Rename 'reclaim' into 'reclaim_memory' (suggested by Roger Pau Monné)
- More wordsmith of the commit message (suggested by Roger Pau Monné)
Changes from v5
(https://lore.kernel.org/linux-block/20191210080628.5264-1-sjpark@amazon.de/)
- 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 checkpatch.pl warnings
Changes from v4
(https://lore.kernel.org/xen-devel/20191209194305.20828-1-sjpark@amazon.com/)
- Remove domain id parameter from the callback (suggested by Juergen
Gross)
- Rename xen-blkback module parameter (suggested by Stefan Nuernburger)
Changes from v3
(https://lore.kernel.org/xen-devel/20191209085839.21215-1-sjpark@amazon.com/)
- Add general callback in xen_driver and use it (suggested by Juergen
Gross)
Changes from v2
(https://lore.kernel.org/linux-block/af195033-23d5-38ed-b73b-f6e2e3b34541@amazon.com)
- Rename the module parameter and variables for brevity
(aggressive shrinking -> squeezing)
Changes from v1
(https://lore.kernel.org/xen-devel/20191204113419.2298-1-sjpark@amazon.com/)
- 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 (5):
xenbus/backend: Add memory pressure handler callback
xenbus/backend: Protect xenbus callback with lock
xen/blkback: Squeeze page pools if a memory pressure is detected
xen/blkback: Remove unnecessary static variable name prefixes
xen/blkback: Consistently insert one empty line between functions
.../ABI/testing/sysfs-driver-xen-blkback | 10 +++++
drivers/block/xen-blkback/blkback.c | 42 +++++++++----------
drivers/block/xen-blkback/common.h | 1 +
drivers/block/xen-blkback/xenbus.c | 37 +++++++++++++---
drivers/xen/xenbus/xenbus_probe.c | 1 +
drivers/xen/xenbus/xenbus_probe_backend.c | 39 +++++++++++++++++
include/xen/xenbus.h | 3 ++
7 files changed, 107 insertions(+), 26 deletions(-)
--
2.17.1
next reply other threads:[~2019-12-18 10:43 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-18 10:42 SeongJae Park [this message]
2019-12-18 10:42 ` [PATCH v12 1/5] xenbus/backend: Add memory pressure handler callback SeongJae Park
2019-12-18 10:42 ` [PATCH v12 2/5] xenbus/backend: Protect xenbus callback with lock SeongJae Park
2019-12-18 12:27 ` Jürgen Groß
2019-12-18 12:42 ` Re: [Xen-devel] " SeongJae Park
2019-12-18 13:30 ` Jürgen Groß
2019-12-18 14:40 ` SeongJae Park
2019-12-18 15:11 ` Jürgen Groß
2019-12-18 17:32 ` SeongJae Park
2019-12-18 10:42 ` [PATCH v12 3/5] xen/blkback: Squeeze page pools if a memory pressure is detected SeongJae Park
2019-12-18 10:42 ` [PATCH v12 4/5] xen/blkback: Remove unnecessary static variable name prefixes SeongJae Park
2019-12-18 10:44 ` [PATCH v12 5/5] xen/blkback: Consistently insert one empty line between functions SeongJae Park
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