From 4352b8aee98005853aa63f57d6377282de17a33f Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 23 Aug 2026 13:28:57 -0700 Subject: Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ... --- tools/lib/python/jobserver.py | 195 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 195 insertions(+) create mode 100755 tools/lib/python/jobserver.py (limited to 'tools/lib/python/jobserver.py') diff --git a/tools/lib/python/jobserver.py b/tools/lib/python/jobserver.py new file mode 100755 index 000000000..0b1ffdf9f --- /dev/null +++ b/tools/lib/python/jobserver.py @@ -0,0 +1,195 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0+ +# +# pylint: disable=C0103,C0209 +# +# + +""" +Interacts with the POSIX jobserver during the Kernel build time. + +A "normal" jobserver task, like the one initiated by a make subprocess would do: + + - open read/write file descriptors to communicate with the job server; + - ask for one slot by calling:: + + claim = os.read(reader, 1) + + - when the job finishes, call:: + + os.write(writer, b"+") # os.write(writer, claim) + +Here, the goal is different: This script aims to get the remaining number +of slots available, using all of them to run a command which handle tasks in +parallel. To to that, it has a loop that ends only after there are no +slots left. It then increments the number by one, in order to allow a +call equivalent to ``make -j$((claim+1))``, e.g. having a parent make creating +$claim child to do the actual work. + +The end goal here is to keep the total number of build tasks under the +limit established by the initial ``make -j$n_proc`` call. + +See: + https://www.gnu.org/software/make/manual/html_node/POSIX-Jobserver.html#POSIX-Jobserver +""" + +import errno +import os +import subprocess +import sys + +def warn(text, *args): + print(f'WARNING: {text}', *args, file = sys.stderr) + +class JobserverExec: + """ + Claim all slots from make using POSIX Jobserver. + + The main methods here are: + + - open(): reserves all slots; + - close(): method returns all used slots back to make; + - run(): executes a command setting PARALLELISM=. + """ + + def __init__(self): + """Initialize internal vars.""" + self.claim = 0 + self.jobs = b"" + self.reader = None + self.writer = None + self.is_open = False + + def open(self): + """Reserve all available slots to be claimed later on.""" + + if self.is_open: + return + self.is_open = True # We only try once + self.claim = None + # + # Check the make flags for "--jobserver=R,W" + # Note that GNU Make has used --jobserver-fds and --jobserver-auth + # so this handles all of them. + # + flags = os.environ.get('MAKEFLAGS', '') + opts = [x for x in flags.split(" ") if x.startswith("--jobserver")] + if not opts: + return + # + # Separate out the provided file descriptors + # + split_opt = opts[-1].split('=', 1) + if len(split_opt) != 2: + warn('unparseable option:', opts[-1]) + return + fds = split_opt[1] + # + # As of GNU Make 4.4, we'll be looking for a named pipe + # identified as fifo:path + # + if fds.startswith('fifo:'): + path = fds[len('fifo:'):] + try: + self.reader = os.open(path, os.O_RDONLY | os.O_NONBLOCK) + self.writer = os.open(path, os.O_WRONLY) + except (OSError, IOError): + warn('unable to open jobserver pipe', path) + return + # + # Otherwise look for integer file-descriptor numbers. + # + else: + split_fds = fds.split(',') + if len(split_fds) != 2: + warn('malformed jobserver file descriptors:', fds) + return + try: + self.reader = int(split_fds[0]) + self.writer = int(split_fds[1]) + except ValueError: + warn('non-integer jobserver file-descriptors:', fds) + return + try: + # + # Open a private copy of reader to avoid setting nonblocking + # on an unexpecting process with the same reader fd. + # + self.reader = os.open(f"/proc/self/fd/{self.reader}", + os.O_RDONLY | os.O_NONBLOCK) + except (IOError, OSError) as e: + warn('Unable to reopen jobserver read-side pipe:', repr(e)) + return + # + # OK, we have the channel to the job server; read out as many jobserver + # slots as possible. + # + while True: + try: + slot = os.read(self.reader, 8) + if not slot: + # + # Something went wrong. Clear self.jobs to avoid writing + # weirdness back to the jobserver and give up. + self.jobs = b"" + warn("unexpected empty token from jobserver;" + " possible invalid '--jobserver-auth=' setting") + self.claim = None + return + except (OSError, IOError) as e: + # + # If there is nothing more to read then we are done. + # + if e.errno == errno.EWOULDBLOCK: + break + # + # Anything else says that something went weird; give back + # the jobs and give up. + # + if self.jobs: + os.write(self.writer, self.jobs) + self.claim = None + warn('error reading from jobserver pipe', repr(e)) + return + self.jobs += slot + # + # Add a bump for our caller's reserveration, since we're just going + # to sit here blocked on our child. + # + self.claim = len(self.jobs) + 1 + + def close(self): + """Return all reserved slots to Jobserver.""" + + if not self.is_open: + return + + # Return all the reserved slots. + if len(self.jobs): + os.write(self.writer, self.jobs) + + self.is_open = False + + def __enter__(self): + self.open() + return self + + def __exit__(self, exc_type, exc_value, exc_traceback): + self.close() + + def run(self, cmd, *args, **pwargs): + """ + Run a command setting PARALLELISM env variable to the number of + available job slots (claim) + 1, e.g. it will reserve claim slots + to do the actual build work, plus one to monitor its children. + """ + self.open() # Ensure that self.claim is set + + # We can only claim parallelism if there was a jobserver (i.e. a + # top-level "-jN" argument) and there were no other failures. Otherwise + # leave out the environment variable and let the child figure out what + # is best. + if self.claim: + os.environ["PARALLELISM"] = str(self.claim) + + return subprocess.call(cmd, *args, **pwargs) -- cgit v1.3.1