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ANDROID: Add a tracepoint for mapping inode to full path
authorJoel Fernandes <joelaf@google.com>
Thu, 14 Mar 2019 21:32:39 +0000 (17:32 -0400)
committerJoel Fernandes <joelaf@google.com>
Tue, 27 Aug 2019 23:26:28 +0000 (23:26 +0000)
commit4bfd1582007fcae7f5459d8bfcf1830f7b867992
tree1e834bb99a9fcc2f9ac2ef5bfa5ca23a182606fe
parentac7fbcaa4c35cdd52594a14e8f8f6b4185349df8
ANDROID: Add a tracepoint for mapping inode to full path

This will be used by eBPF and the iorapd project for high speed
inode/dev numbers to file path lookup. Look at the inodemap CL for more
details about of eBPF and iorapd using the tracepoint.

This is planned to be used by the inodemap BPF program. Also, ART folks
have been using this tracepoint for debugging "unknown inode numer"
issues.

The tracepoint will be out of tree, and not sent upstream, since VFS
developers don't accept tracepoints strictly.

Test: Run "find /" command in emulator and measure completion time
with/without treacepoint. find does a flood of lookups which stresses
the tracepoint. No performance change observed.
Test: eBPF prototypes (wip) successfully read data from the tracepoint.

OOT Bug: 139663736
Bug: 135143784
Bug: 137393447
Change-Id: I657f374659673a9c8853530d73c0622dbdbab146
Signed-off-by: Joel Fernandes <joelaf@google.com>
(cherry picked from commit 987732fcbbe3ea78368c28e5a0d0d236be61420f)
(cherry picked from commit 2104283a8d7349011860d9bffb8a3d25456e6d20)
fs/namei.c
include/trace/events/namei.h [new file with mode: 0644]