Be increasingly aggressive about fstrim if it isn't being run
The current heuristics depend on devices being alive at midnight+ in
order to run periodic background fstrim operations. This unfortunately
means that people who routinely turn their devices off overnight wind
up with their devices *never* running fstrim, and this causes major
performance and disk-life problems.
We now backstop this very-friendly schedule with an increasingly
aggressive one. If the device goes a defined time without a background
fstrim, we then force the fstrim at the next reboot. Once the
device hits the midnight+ idle fstrim request time, then we already
aggressively attempt to fstrim at the first available moment
thereafter, even if it's days/weeks later without a reboot.
'Available' here means charging + device idle. If the device never
becomes idle then we can't do much without rendering an in-use device
inoperable for some number of minutes -- but we have no evidence of
devices ever failing to run fstrim due to this usage pattern.
A new Settings.Global element (type 'long', called
"fstrim_mandatory_interval") is the source of the backstop time. If
this element is zero or negative, no mandatory boot-time fstrim will
ever be performed. If the element is not supplied on a given device,
the default backstop is 3 days.
Adds a new string to display in the upgrading dialog when doing
the fstrim. Note it is too late for this to be localized, but since
this operation can take a long time it is probably better to have
it show *something* even if not localized, rather than just sit there.
Bug 18486922
Change-Id: I5b265ca0a65570fb8931251aa1ac37b530635a2c
diff --git a/core/java/android/provider/Settings.java b/core/java/android/provider/Settings.java
index 79e84d9..73c7cc3 100644
--- a/core/java/android/provider/Settings.java
+++ b/core/java/android/provider/Settings.java
@@ -5544,6 +5544,13 @@
public static final String PACKAGE_VERIFIER_INCLUDE_ADB = "verifier_verify_adb_installs";
/**
+ * Time since last fstrim (milliseconds) after which we force one to happen
+ * during device startup. If unset, the default is 3 days.
+ * @hide
+ */
+ public static final String FSTRIM_MANDATORY_INTERVAL = "fstrim_mandatory_interval";
+
+ /**
* The interval in milliseconds at which to check packet counts on the
* mobile data interface when screen is on, to detect possible data
* connection problems.