linux.git/drivers/hwtracing, branch master Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git [tree-wide] finally take no_llseek out 2024-09-27T15:18:43+00:00 Al Viro viro@zeniv.linux.org.uk 2024-09-27T01:56:11+00:00 cb787f4ac0c2e439ea8d7e6387b925f74576bdf8 no_llseek had been defined to NULL two years ago, in commit 868941b14441 ("fs: remove no_llseek") To quote that commit, At -rc1 we'll need do a mechanical removal of no_llseek - git grep -l -w no_llseek | grep -v porting.rst | while read i; do sed -i '/\<no_llseek\>/d' $i done would do it. Unfortunately, that hadn't been done. Linus, could you do that now, so that we could finally put that thing to rest? All instances are of the form .llseek = no_llseek, so it's obviously safe. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
no_llseek had been defined to NULL two years ago, in commit 868941b14441
("fs: remove no_llseek")

To quote that commit,

  At -rc1 we'll need do a mechanical removal of no_llseek -

  git grep -l -w no_llseek | grep -v porting.rst | while read i; do
	sed -i '/\<no_llseek\>/d' $i
  done

  would do it.

Unfortunately, that hadn't been done.  Linus, could you do that now, so
that we could finally put that thing to rest? All instances are of the
form
	.llseek = no_llseek,
so it's obviously safe.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
coresight: Make trace ID map spinlock local to the map 2024-08-20T14:02:38+00:00 James Clark james.clark@arm.com 2024-07-22T10:11:59+00:00 988d40a4d4e7d671305bea501562a5d1a1d479fa Reduce contention on the lock by replacing the global lock with one for each map. Signed-off-by: James Clark <james.clark@arm.com> Reviewed-by: Mike Leach <mike.leach@linaro.org> Signed-off-by: James Clark <james.clark@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20240722101202.26915-18-james.clark@linaro.org 
Reduce contention on the lock by replacing the global lock with one for
each map.

Signed-off-by: James Clark <james.clark@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240722101202.26915-18-james.clark@linaro.org
coresight: Emit sink ID in the HW_ID packets 2024-08-20T14:02:38+00:00 James Clark james.clark@arm.com 2024-07-22T10:11:58+00:00 487eec8da80aef16229d30429f1b26090b1bf0eb For Perf to be able to decode when per-sink trace IDs are used, emit the sink that's being written to for each ETM. Perf currently errors out if it sees a newer packet version so instead of bumping it, add a new minor version field. This can be used to signify new versions that have backwards compatible fields. Considering this change is only for high core count machines, it doesn't make sense to make a breaking change for everyone. Signed-off-by: James Clark <james.clark@arm.com> Tested-by: Leo Yan <leo.yan@arm.com> Reviewed-by: Mike Leach <mike.leach@linaro.org> Signed-off-by: James Clark <james.clark@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20240722101202.26915-17-james.clark@linaro.org 
For Perf to be able to decode when per-sink trace IDs are used, emit the
sink that's being written to for each ETM.

Perf currently errors out if it sees a newer packet version so instead
of bumping it, add a new minor version field. This can be used to
signify new versions that have backwards compatible fields. Considering
this change is only for high core count machines, it doesn't make sense
to make a breaking change for everyone.

Signed-off-by: James Clark <james.clark@arm.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240722101202.26915-17-james.clark@linaro.org
coresight: Remove pending trace ID release mechanism 2024-08-20T14:02:38+00:00 James Clark james.clark@arm.com 2024-07-22T10:11:57+00:00 de0029fdde86092c75472c92e56a962f4edee0f6 Pending the release of IDs was a way of managing concurrent sysfs and Perf sessions in a single global ID map. Perf may have finished while sysfs hadn't, and Perf shouldn't release the IDs in use by sysfs and vice versa. Now that Perf uses its own exclusive ID maps, pending release doesn't result in any different behavior than just releasing all IDs when the last Perf session finishes. As part of the per-sink trace ID change, we would have still had to make the pending mechanism work on a per-sink basis, due to the overlapping ID allocations, so instead of making that more complicated, just remove it. Signed-off-by: James Clark <james.clark@arm.com> Reviewed-by: Mike Leach <mike.leach@linaro.org> Signed-off-by: James Clark <james.clark@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20240722101202.26915-16-james.clark@linaro.org 
Pending the release of IDs was a way of managing concurrent sysfs and
Perf sessions in a single global ID map. Perf may have finished while
sysfs hadn't, and Perf shouldn't release the IDs in use by sysfs and
vice versa.

Now that Perf uses its own exclusive ID maps, pending release doesn't
result in any different behavior than just releasing all IDs when the
last Perf session finishes. As part of the per-sink trace ID change, we
would have still had to make the pending mechanism work on a per-sink
basis, due to the overlapping ID allocations, so instead of making that
more complicated, just remove it.

Signed-off-by: James Clark <james.clark@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240722101202.26915-16-james.clark@linaro.org
coresight: Use per-sink trace ID maps for Perf sessions 2024-08-20T14:02:38+00:00 James Clark james.clark@arm.com 2024-07-22T10:11:56+00:00 5ad628a7617607baac53745f8025638b967470a2 This will allow sessions with more than CORESIGHT_TRACE_IDS_MAX ETMs as long as there are fewer than that many ETMs connected to each sink. Each sink owns its own trace ID map, and any Perf session connecting to that sink will allocate from it, even if the sink is currently in use by other users. This is similar to the existing behavior where the dynamic trace IDs are constant as long as there is any concurrent Perf session active. It's not completely optimal because slightly more IDs will be used than necessary, but the optimal solution involves tracking the PIDs of each session and allocating ID maps based on the session owner. This is difficult to do with the combination of per-thread and per-cpu modes and some scheduling issues. The complexity of this isn't likely to worth it because even with multiple users they'd just see a difference in the ordering of ID allocations rather than hitting any limits (unless the hardware does have too many ETMs connected to one sink). Signed-off-by: James Clark <james.clark@arm.com> Reviewed-by: Mike Leach <mike.leach@linaro.org> Signed-off-by: James Clark <james.clark@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20240722101202.26915-15-james.clark@linaro.org 
This will allow sessions with more than CORESIGHT_TRACE_IDS_MAX ETMs
as long as there are fewer than that many ETMs connected to each sink.

Each sink owns its own trace ID map, and any Perf session connecting to
that sink will allocate from it, even if the sink is currently in use by
other users. This is similar to the existing behavior where the dynamic
trace IDs are constant as long as there is any concurrent Perf session
active. It's not completely optimal because slightly more IDs will be
used than necessary, but the optimal solution involves tracking the PIDs
of each session and allocating ID maps based on the session owner. This
is difficult to do with the combination of per-thread and per-cpu modes
and some scheduling issues. The complexity of this isn't likely to worth
it because even with multiple users they'd just see a difference in the
ordering of ID allocations rather than hitting any limits (unless the
hardware does have too many ETMs connected to one sink).

Signed-off-by: James Clark <james.clark@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240722101202.26915-15-james.clark@linaro.org
coresight: Make CPU id map a property of a trace ID map 2024-08-20T14:02:38+00:00 James Clark james.clark@arm.com 2024-07-22T10:11:55+00:00 d53c8253c7822fbc524adcd950e7c6de6a229c99 The global CPU ID mappings won't work for per-sink ID maps so move it to the ID map struct. coresight_trace_id_release_all_pending() is hard coded to operate on the default map, but once Perf sessions use their own maps the pending release mechanism will be deleted. So it doesn't need to be extended to accept a trace ID map argument at this point. Signed-off-by: James Clark <james.clark@arm.com> Reviewed-by: Mike Leach <mike.leach@linaro.org> Tested-by: Leo Yan <leo.yan@arm.com> Signed-off-by: James Clark <james.clark@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20240722101202.26915-14-james.clark@linaro.org 
The global CPU ID mappings won't work for per-sink ID maps so move it to
the ID map struct. coresight_trace_id_release_all_pending() is hard
coded to operate on the default map, but once Perf sessions use their
own maps the pending release mechanism will be deleted. So it doesn't
need to be extended to accept a trace ID map argument at this point.

Signed-off-by: James Clark <james.clark@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Tested-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240722101202.26915-14-james.clark@linaro.org
coresight: Expose map arguments in trace ID API 2024-08-20T14:02:38+00:00 James Clark james.clark@arm.com 2024-07-22T10:11:54+00:00 7e52877868ae2546ead8ba07cdf1d3e4c9e931f7 The trace ID API is currently hard coded to always use the global map. Add public versions that allow the map to be passed in so that Perf mode can use per-sink maps. Keep the non-map versions so that sysfs mode can continue to use the default global map. System ID functions are unchanged because they will always use the default map. Signed-off-by: James Clark <james.clark@arm.com> Reviewed-by: Mike Leach <mike.leach@linaro.org> Tested-by: Leo Yan <leo.yan@arm.com> Signed-off-by: James Clark <james.clark@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20240722101202.26915-13-james.clark@linaro.org 
The trace ID API is currently hard coded to always use the global map.
Add public versions that allow the map to be passed in so that Perf
mode can use per-sink maps. Keep the non-map versions so that sysfs
mode can continue to use the default global map.

System ID functions are unchanged because they will always use the
default map.

Signed-off-by: James Clark <james.clark@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Tested-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240722101202.26915-13-james.clark@linaro.org
coresight: Move struct coresight_trace_id_map to common header 2024-08-20T14:02:37+00:00 James Clark james.clark@arm.com 2024-07-22T10:11:53+00:00 acb0184fe9bca3bb7103dadc76ba9d38c969ca86 The trace ID maps will need to be created and stored by the core and Perf code so move the definition up to the common header. Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Mike Leach <mike.leach@linaro.org> Signed-off-by: James Clark <james.clark@arm.com> Tested-by: Leo Yan <leo.yan@arm.com> Tested-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com> Signed-off-by: James Clark <james.clark@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20240722101202.26915-12-james.clark@linaro.org 
The trace ID maps will need to be created and stored by the core and
Perf code so move the definition up to the common header.

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@arm.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Tested-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240722101202.26915-12-james.clark@linaro.org
coresight: Clarify comments around the PID of the sink owner 2024-08-20T14:02:37+00:00 James Clark james.clark@arm.com 2024-07-22T10:11:52+00:00 eda1d11979c03f0104ca59ec4a0478cd52fa20de "Process being monitored" and "pid of the process to monitor" imply that this would be the same PID if there were two sessions targeting the same process. But this is actually the PID of the process that did the Perf event open call, rather than the target of the session. So update the comments to make this clearer. Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Mike Leach <mike.leach@linaro.org> Signed-off-by: James Clark <james.clark@arm.com> Tested-by: Leo Yan <leo.yan@arm.com> Tested-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com> Signed-off-by: James Clark <james.clark@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20240722101202.26915-11-james.clark@linaro.org 
"Process being monitored" and "pid of the process to monitor" imply that
this would be the same PID if there were two sessions targeting the same
process. But this is actually the PID of the process that did the Perf
event open call, rather than the target of the session. So update the
comments to make this clearer.

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@arm.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Tested-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240722101202.26915-11-james.clark@linaro.org
coresight: Remove unused ETM Perf stubs 2024-08-20T14:02:37+00:00 James Clark james.clark@arm.com 2024-07-22T10:11:51+00:00 34172002bdac28dabbb846f191a86454bb226c7a This file is never included anywhere if CONFIG_CORESIGHT is not set so they are unused and aren't currently compile tested with any config so remove them. Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Mike Leach <mike.leach@linaro.org> Signed-off-by: James Clark <james.clark@arm.com> Tested-by: Leo Yan <leo.yan@arm.com> Tested-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com> Signed-off-by: James Clark <james.clark@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20240722101202.26915-10-james.clark@linaro.org 
This file is never included anywhere if CONFIG_CORESIGHT is not set so
they are unused and aren't currently compile tested with any config so
remove them.

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@arm.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Tested-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240722101202.26915-10-james.clark@linaro.org