mirror of
https://github.com/torvalds/linux.git
synced 2026-01-25 15:03:52 +08:00
3ca55ca225
It is useful to be able to access current->mm at task exit to, say, record a bunch of VMA information right before the task exits (e.g., for stack symbolization reasons when dealing with short-lived processes that exit in the middle of profiling session). Currently, trace_sched_process_exit() is triggered after exit_mm() which resets current->mm to NULL making this tracepoint unsuitable for inspecting and recording task's mm_struct-related data when tracing process lifetimes. There is a particularly suitable place, though, right after taskstats_exit() is called, but before we do exit_mm() and other exit_*() resource teardowns. taskstats performs a similar kind of accounting that some applications do with BPF, and so co-locating them seems like a good fit. So that's where trace_sched_process_exit() is moved with this patch. Also, existing trace_sched_process_exit() tracepoint is notoriously missing `group_dead` flag that is certainly useful in practice and some of our production applications have to work around this. So plumb `group_dead` through while at it, to have a richer and more complete tracepoint. Note that we can't use sched_process_template anymore, and so we use TRACE_EVENT()-based tracepoint definition. But all the field names and order, as well as assign and output logic remain intact. We just add one extra field at the end in backwards-compatible way. [andrii@kernel.org: document sched_process_exit and sched_process_template relation] Link: https://lkml.kernel.org/r/20250403174120.4087794-1-andrii@kernel.org Link: https://lkml.kernel.org/r/20250402180925.90914-1-andrii@kernel.org Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> Acked-by: Oleg Nesterov <oleg@redhat.com> Suggested-by: Ingo Molnar <mingo@kernel.org> Cc: Alexander Potapenko <glider@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.