On Thu, 13 Jul 2023 17:03:14 +0530 Ajay Kaher <akaher@xxxxxxxxxx> wrote: > Events Tracing infrastructure contains lot of files, directories > (internally in terms of inodes, dentries). And ends up by consuming > memory in MBs. We can have multiple events of Events Tracing, which > further requires more memory. > > Instead of creating inodes/dentries, eventfs could keep meta-data and > skip the creation of inodes/dentries. As and when require, eventfs will > create the inodes/dentries only for required files/directories. > Also eventfs would delete the inodes/dentries once no more requires > but preserve the meta data. > > Tracing events took ~9MB, with this approach it took ~4.5MB > for ~10K files/dir. I think we are very close to getting this in for the next merge window. I ran several tests and so far it's holding up! I made a bunch of nits for this series, but nothing major. Mostly fixing up change logs and comments, as well as some naming conventions and reorganizing the series a little bit. Anyway, I'm hoping that v5 will be ready to go into linux-next. Thanks a lot Ajay for working on this! -- Steve > > v3: > Patch 3,4,5,7,9: > removed all the eventfs_rwsem code and replaced it with an srcu > lock for the readers, and a mutex to synchronize the writers of > the list. > > Patch 2: moved 'tracefs_inode' and 'get_tracefs()' to v4 03/10 > > Patch 3: moved the struct eventfs_file and eventfs_inode into event_inode.c > as it really should not be exposed to all users. > > Patch 5: added a recursion check to eventfs_remove_rec() as it is really > dangerous to have unchecked recursion in the kernel (we do have > a fixed size stack). > > have the free use srcu callbacks. After the srcu grace periods > are done, it adds the eventfs_file onto a llist (lockless link > list) and wakes up a work queue. Then the work queue does the > freeing (this needs to be done in task/workqueue context, as > srcu callbacks are done in softirq context). > > Patch 6: renamed: > eventfs_create_file() -> create_file() > eventfs_create_dir() -> create_dir() > > v2: > Patch 01: new patch:'Require all trace events to have a TRACE_SYSTEM' > Patch 02: moved from v1 1/9 > Patch 03: moved from v1 2/9 > As suggested by Zheng Yejian, introduced eventfs_prepare_ef() > helper function to add files or directories to eventfs > fix WARNING reported by kernel test robot in v1 8/9 > Patch 04: moved from v1 3/9 > used eventfs_prepare_ef() to add files > fix WARNING reported by kernel test robot in v1 8/9 > Patch 05: moved from v1 4/9 > fix compiling warning reported by kernel test robot in v1 4/9 > Patch 06: moved from v1 5/9 > Patch 07: moved from v1 6/9 > Patch 08: moved from v1 7/9 > Patch 09: moved from v1 8/9 > rebased because of v3 01/10 > Patch 10: moved from v1 9/9 > > v1: > Patch 1: add header file > Patch 2: resolved kernel test robot issues > protecting eventfs lists using nested eventfs_rwsem > Patch 3: protecting eventfs lists using nested eventfs_rwsem > Patch 4: improve events cleanup code to fix crashes > Patch 5: resolved kernel test robot issues > removed d_instantiate_anon() calls > Patch 6: resolved kernel test robot issues > fix kprobe test in eventfs_root_lookup() > protecting eventfs lists using nested eventfs_rwsem > Patch 7: remove header file > Patch 8: pass eventfs_rwsem as argument to eventfs functions > called eventfs_remove_events_dir() instead of tracefs_remove() > from event_trace_del_tracer() > Patch 9: new patch to fix kprobe test case > > Ajay Kaher (9): > tracefs: Rename some tracefs function > eventfs: Implement eventfs dir creation functions > eventfs: Implement eventfs file add functions > eventfs: Implement eventfs file, directory remove function > eventfs: Implement functions to create eventfs files and directories > eventfs: Implement eventfs lookup, read, open functions > eventfs: Implement tracefs_inode_cache > eventfs: Move tracing/events to eventfs > test: ftrace: Fix kprobe test for eventfs > > Steven Rostedt (Google) (1): > tracing: Require all trace events to have a TRACE_SYSTEM > > fs/tracefs/Makefile | 1 + > fs/tracefs/event_inode.c | 711 ++++++++++++++++++ > fs/tracefs/inode.c | 124 ++- > fs/tracefs/internal.h | 25 + > include/linux/trace_events.h | 1 + > include/linux/tracefs.h | 32 + > kernel/trace/trace.h | 2 +- > kernel/trace/trace_events.c | 78 +- > .../ftrace/test.d/kprobe/kprobe_args_char.tc | 4 +- > .../test.d/kprobe/kprobe_args_string.tc | 4 +- > 10 files changed, 930 insertions(+), 52 deletions(-) > create mode 100644 fs/tracefs/event_inode.c > create mode 100644 fs/tracefs/internal.h >
