This changes comes with several different refactorings all rolled into one,
unfotunately I couldn't find a way to pull them apart:
- First of all annotations now can either recorded (that is, we copy the value
and have the crash reporting code own the copy) or registered. Several
annotations are changed to use this functionality so that we don't need to
update them as their value change.
- The code in the exception handler is modified to read the annotations from
the mozannotation_client crate. This has the unfortunate side-effect that
we need three different bits of code to serialize them: one for annotations
read from a child process, one for reading annotations from the main process
outside of the exception handler and one for reading annotations from the
main process within the exception handler. As we move to fully
out-of-process crash reporting the last two methods will go away.
- The mozannotation_client crate now doesn't record annotation types anymore.
I realized as I was working on this that storing types at runtime has two
issues: the first one is that buggy code might change the type of an
annotation (that is record it under two different types at two different
moments), the second issue is that types might become corrupt during a
crash, so better enforce them at annotation-writing time. The end result is
that the mozannotation_* crates now only store byte buffers, track the
format the data is stored in (null-terminated string, fixed size buffer,
etc...) but not the type of data each annotation is supposed to contain.
- Which brings us to the next change: concrete types for annotations are now
enforced when they're written out. If an annotation doesn't match the
expected type it's skipped. Storing an annotation with the wrong type will
also trigger an assertion in debug builds.
Differential Revision: https://phabricator.services.mozilla.com/D195248
Adds a crash annotation, `LinuxUnderMemoryPressure`, which the memory pressure monitor updates based on whether or not it is under memory pressure.
Differential Revision: https://phabricator.services.mozilla.com/D133555
This introduces a low memory watcher that dispatches an offthread read of /proc/meminfo every 5000/1000ms depending on memory levels, then determines which information to act on. It works like this:
- Get a percentage of `MemAvailable` versus `MemTotal`.
- If memory drops below 5% availability, we are in a memory pressure scenario
- If `MemAvailable` is not large enough to accommodate a content process, we are in a memory pressure scenario
- If we are in a memory pressure scenario, notify the observers from the main thread.
The value I decided to use to represent a content process was based on observation and should be adjusted if it is not representative of what we consider a "typical" content process.
Differential Revision: https://phabricator.services.mozilla.com/D117972
This introduces a low memory watcher that dispatches an offthread read of /proc/meminfo every 5000/1000ms depending on memory levels, then determines which information to act on. It works like this:
- Get a percentage of `MemAvailable` versus `MemTotal`.
- If memory drops below 5% availability, we are in a memory pressure scenario
- If `MemAvailable` is not large enough to accommodate a content process, we are in a memory pressure scenario
- If we are in a memory pressure scenario, notify the observers from the main thread.
The value I decided to use to represent a content process was based on observation and should be adjusted if it is not representative of what we consider a "typical" content process.
Differential Revision: https://phabricator.services.mozilla.com/D117972
This introduces a low memory watcher that dispatches an offthread read of /proc/meminfo every 5000/1000ms depending on memory levels, then determines which information to act on. It works like this:
- Get a percentage of `MemAvailable` versus `MemTotal`.
- If memory drops below 5% availability, we are in a memory pressure scenario
- If `MemAvailable` is not large enough to accommodate a content process, we are in a memory pressure scenario
- If we are in a memory pressure scenario, notify the observers from the main thread.
The value I decided to use to represent a content process was based on observation and should be adjusted if it is not representative of what we consider a "typical" content process.
Differential Revision: https://phabricator.services.mozilla.com/D117972
Gabriele Svelto