Attachment 45967 Details for Bug 34936 – Patch to disable spinup-avoidance hooks if no rotational devices present

[patch] Patch to disable spinup-avoidance hooks if no rotational devices present

0001-Disable-spinup-avoidance-measures-for-non-rotational.patch (text/plain), 2.54 KB, created by Josh Triplett on 2011-04-22 12:58:26 UTC

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Creator: Josh Triplett

Created: 2011-04-22 12:58:26 UTC

Size: 2.54 KB

patch

obsolete

>From 4bab928965e4c6411a96a9edaef484b53425fedb Mon Sep 17 00:00:00 2001
>From: Josh Triplett <josh@joshtriplett.org>
>Date: Fri, 22 Apr 2011 12:50:19 -0700
>Subject: [PATCH] Disable spinup-avoidance measures for non-rotational disks
>
>SSDs don't need to spin up or down, and they don't need the OS's help to
>do sensible power management when idle; thus, the spinup-avoidance
>measures increase the risk of data loss (by delaying writeback) without
>saving power.  Add a new have_rotational_disks common function, and
>check it from journal-commit, laptop-mode, and xfs_buffer; exit $NA if
>the system has no rotational disks.
>---
> pm/functions.in           |    9 +++++++++
> pm/power.d/journal-commit |    4 ++++
> pm/power.d/laptop-mode    |    1 +
> pm/power.d/xfs_buffer     |    3 +++
> 4 files changed, 17 insertions(+), 0 deletions(-)
>
>diff --git a/pm/functions.in b/pm/functions.in
>index bd649db..9efd071 100644
>--- a/pm/functions.in
>+++ b/pm/functions.in
>@@ -249,3 +249,12 @@ dbus_send ()
> 	command dbus-send "$@" 2>/dev/null || return $NA
> }
> 
>+have_rotational_disks ()
>+{
>+	for r in /sys/block/*/queue/rotational ; do
>+		# Skip loop devices, which always show up as rotational
>+		[ "${r#/sys/block/loop[0-9]}" != "$r" ] && continue
>+		[ "$(cat "$r")" -eq 1 ] && return 0
>+	done
>+	return 1
>+}
>diff --git a/pm/power.d/journal-commit b/pm/power.d/journal-commit
>index 5c0fc16..223228d 100644
>--- a/pm/power.d/journal-commit
>+++ b/pm/power.d/journal-commit
>@@ -19,6 +19,10 @@ We currently only handle EXT3 filesystems
> EOF
> }
> 
>+# FIXME: This should really check the device corresponding to each filesystem.
>+# However, most laptops only have one disk, so this works reasonably well.
>+have_rotational_disks || exit $NA
>+
> # actually remount the file system
> remount_fs()
> {
>diff --git a/pm/power.d/laptop-mode b/pm/power.d/laptop-mode
>index 601b260..07bb4f9 100644
>--- a/pm/power.d/laptop-mode
>+++ b/pm/power.d/laptop-mode
>@@ -46,6 +46,7 @@ memory every 10 minutes if dirty memory never hits 40% of system memory.
> EOF
> }
> 
>+have_rotational_disks || exit $NA
> [ -w $VM/laptop_mode -a -w $VM/dirty_ratio ] || exit $NA
> 
> read_values() {
>diff --git a/pm/power.d/xfs_buffer b/pm/power.d/xfs_buffer
>index d21e845..ad506b1 100644
>--- a/pm/power.d/xfs_buffer
>+++ b/pm/power.d/xfs_buffer
>@@ -30,6 +30,9 @@ Defaults to 60000, or 10 minutes.
> EOF
> }
> 
>+# FIXME: This should really check the device corresponding to each filesystem.
>+# However, most laptops only have one disk, so this works reasonably well.
>+have_rotational_disks || exit $NA
> [ -f $XFS/age_buffer_centisecs ] || exit $NA
> 
> read_values() {
>-- 
>1.7.4.4
>

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