Re: [PATCH - resend*2] VFS: use synchronize_rcu_expedited() in namespace_unlock()

2018-11-29 Thread NeilBrown
On Thu, Nov 29 2018, Al Viro wrote: > On Fri, Nov 30, 2018 at 10:33:18AM +1100, NeilBrown wrote: >> >> The synchronize_rcu() in namespace_unlock() is called every time >> a filesystem is unmounted. If a great many filesystems are mounted, >> this can cause a noticable slow-down in, for example,

Re: [PATCH - resend*2] VFS: use synchronize_rcu_expedited() in namespace_unlock()

2018-11-29 Thread NeilBrown
On Thu, Nov 29 2018, Al Viro wrote: > On Fri, Nov 30, 2018 at 10:33:18AM +1100, NeilBrown wrote: >> >> The synchronize_rcu() in namespace_unlock() is called every time >> a filesystem is unmounted. If a great many filesystems are mounted, >> this can cause a noticable slow-down in, for example,

Re: [PATCH - resend*2] VFS: use synchronize_rcu_expedited() in namespace_unlock()

2018-11-29 Thread Al Viro
On Fri, Nov 30, 2018 at 10:33:18AM +1100, NeilBrown wrote: > > The synchronize_rcu() in namespace_unlock() is called every time > a filesystem is unmounted. If a great many filesystems are mounted, > this can cause a noticable slow-down in, for example, system shutdown. > > The sequence: >

Re: [PATCH - resend*2] VFS: use synchronize_rcu_expedited() in namespace_unlock()

2018-11-29 Thread Al Viro
On Fri, Nov 30, 2018 at 10:33:18AM +1100, NeilBrown wrote: > > The synchronize_rcu() in namespace_unlock() is called every time > a filesystem is unmounted. If a great many filesystems are mounted, > this can cause a noticable slow-down in, for example, system shutdown. > > The sequence: >

Re: [PATCH - resend*2] VFS: use synchronize_rcu_expedited() in namespace_unlock()

2018-11-29 Thread NeilBrown
The synchronize_rcu() in namespace_unlock() is called every time a filesystem is unmounted. If a great many filesystems are mounted, this can cause a noticable slow-down in, for example, system shutdown. The sequence: mkdir -p /tmp/Mtest/{0..5000} time for i in /tmp/Mtest/*; do mount -t

Re: [PATCH - resend*2] VFS: use synchronize_rcu_expedited() in namespace_unlock()

2018-11-29 Thread NeilBrown
The synchronize_rcu() in namespace_unlock() is called every time a filesystem is unmounted. If a great many filesystems are mounted, this can cause a noticable slow-down in, for example, system shutdown. The sequence: mkdir -p /tmp/Mtest/{0..5000} time for i in /tmp/Mtest/*; do mount -t