Nick Piggin <npiggin@xxxxxxxxx> writes:
BTW one way to make the slow path faster would be to start sharing
per cpu locks inside a core on SMT at least. The same cores have the same
caches and sharing cache lines is free. That would cut it in half
on a 2x HT system.
> -
> static int event;
> static DEFINE_IDA(mnt_id_ida);
> static DEFINE_IDA(mnt_group_ida);
> +static DEFINE_SPINLOCK(mnt_id_lock);
Can you add a scope comment to that lock?
> @@ -623,39 +653,43 @@ static inline void __mntput(struct vfsmo
> void mntput_no_expire(struct vfsmount *mnt)
> {
> repeat:
> - if (atomic_dec_and_lock(&mnt->mnt_count, &vfsmount_lock)) {
> - if (likely(!mnt->mnt_pinned)) {
> - spin_unlock(&vfsmount_lock);
> - __mntput(mnt);
> - return;
> - }
> - atomic_add(mnt->mnt_pinned + 1, &mnt->mnt_count);
> - mnt->mnt_pinned = 0;
> - spin_unlock(&vfsmount_lock);
> - acct_auto_close_mnt(mnt);
> - goto repeat;
> + if (atomic_add_unless(&mnt->mnt_count, -1, 1))
> + return;
Hmm that's a unrelated change?
The rest looks all good and quite straight forward
Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
-Andi
--
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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