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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 21:48:46 +0000 (21:48 +0000)
commit76ae5009ed0a1c41260e28d5b42f94c153e86088
tree125491fcc6920f6c2b86ccee6957eabb03f294e3
parent476e7ea6e7a1f65677725b1683b93b7cec831488
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)
fs/namei.c
include/trace/events/namei.h [new file with mode: 0644]