github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-06-04 04:23:35 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

proc/kcore: mark proc entry as permanent

Browse Source 
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>
This commit is contained in:
Omar Sandoval 2024-11-08 17:28:39 -08:00 committed by Christian Brauner
parent 40384c840e
commit c9136fad4c
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
1 changed files with 1 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
fs/proc/kcore.c
View File

@ -663,6 +663,7 @@ static int release_kcore(struct inode *inode, struct file *file)
}
static const struct proc_ops kcore_proc_ops = {
.proc_flags = PROC_ENTRY_PERMANENT,
.proc_read_iter = read_kcore_iter,
.proc_open = open_kcore,
.proc_release = release_kcore,