]> git.apps.os.sepia.ceph.com Git - ceph-client.git/commit
proc/kcore: mark proc entry as permanent
authorOmar Sandoval <osandov@fb.com>
Sat, 9 Nov 2024 01:28:39 +0000 (17:28 -0800)
committerChristian Brauner <brauner@kernel.org>
Mon, 2 Dec 2024 10:21:03 +0000 (11:21 +0100)
commitc9136fad4c08288be26aaff3e63d634545b32a85
tree5796d3093f1e61a64d1a1c2ee333f809a9ba742c
parent40384c840ea1944d7c5a392e8975ed088ecf0b37
proc/kcore: mark proc entry as permanent

drgn reads from /proc/kcore to debug the running kernel. For many drgn
scripts, /proc/kcore is actually a bottleneck.

use_pde() and unuse_pde() in prog_reg_read() show up hot in profiles.
Since the entry for /proc/kcore can never be removed, this is useless
overhead that can be trivially avoided by marking the entry as
permanent.

In my benchmark, this reduces the time per read by about 20 nanoseconds,
from 235 nanoseconds per read to 215.

Link: https://github.com/osandov/drgn/issues/106
Signed-off-by: Omar Sandoval <osandov@fb.com>
Link: https://lore.kernel.org/r/60873e6afcfda3f08d0456f19e4733612afcf134.1731115587.git.osandov@fb.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
fs/proc/kcore.c