This moves a kfree outside a spinlock to help scaling on larger (512 core)
systems. This should be some relief until we can move the section to use
the rcu.
I ran a simple test which just reads from /proc/cpuinfo.
Lower is better, as you can see the worst case scenario is improved.
baseline moved kfree
tasks read-sec read-sec
1 0.0141 0.0141
2 0.0140 0.0140
4 0.0140 0.0141
8 0.0145 0.0145
16 0.0553 0.0548
32 0.1688 0.1622
64 0.5017 0.3856
128 1.7005 0.9710
256 5.2513 2.6519
512 8.0529 6.2976
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Acked-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Signed-off-by: Nathan Zimmer <nzimmer@xxxxxxx>
---
fs/proc/inode.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 439ae688..863608b 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -403,11 +403,10 @@ static int proc_reg_release(struct inode *inode, struct file *file)
}
pde->pde_users++;
release = pde->proc_fops->release;
- if (pdeo) {
+ if (pdeo)
list_del(&pdeo->lh);
- kfree(pdeo);
- }
spin_unlock(&pde->pde_unload_lock);
+ kfree(pdeo);
if (release)
rv = release(inode, file);
--
1.8.1.2
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