Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-10-01 Thread Dave Hansen
On Mon, 2007-09-24 at 12:42 -0700, Andrew Morton wrote: > On Mon, 24 Sep 2007 12:28:11 -0700 > Dave Hansen <[EMAIL PROTECTED]> wrote: > > On Mon, 2007-09-24 at 18:54 +0100, Christoph Hellwig wrote: > > > As we already say in various messages the percpu counters in here > > > look rather fishy.

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-10-01 Thread Dave Hansen
On Mon, 2007-09-24 at 12:42 -0700, Andrew Morton wrote: On Mon, 24 Sep 2007 12:28:11 -0700 Dave Hansen [EMAIL PROTECTED] wrote: On Mon, 2007-09-24 at 18:54 +0100, Christoph Hellwig wrote: As we already say in various messages the percpu counters in here look rather fishy. I'd recomment

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-25 Thread Dave Hansen
On Mon, 2007-09-24 at 16:15 -0700, Andrew Morton wrote: > On Mon, 24 Sep 2007 16:05:37 -0700 > Dave Hansen <[EMAIL PROTECTED]> wrote: > > > On Mon, 2007-09-24 at 15:25 -0700, Andrew Morton wrote: > > > hm. I saw that warning on my 2-way. It has CONFIG_NR_CPUS=8 so perhaps > > > the kernel has

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-25 Thread Dave Hansen
On Mon, 2007-09-24 at 16:15 -0700, Andrew Morton wrote: On Mon, 24 Sep 2007 16:05:37 -0700 Dave Hansen [EMAIL PROTECTED] wrote: On Mon, 2007-09-24 at 15:25 -0700, Andrew Morton wrote: hm. I saw that warning on my 2-way. It has CONFIG_NR_CPUS=8 so perhaps the kernel has decided that

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Andrew Morton
On Mon, 24 Sep 2007 16:05:37 -0700 Dave Hansen <[EMAIL PROTECTED]> wrote: > On Mon, 2007-09-24 at 15:25 -0700, Andrew Morton wrote: > > hm. I saw that warning on my 2-way. It has CONFIG_NR_CPUS=8 so perhaps > > the kernel has decided that this machine can possibly have eight CPUs. > > > > It's

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Dave Hansen
On Mon, 2007-09-24 at 15:25 -0700, Andrew Morton wrote: > hm. I saw that warning on my 2-way. It has CONFIG_NR_CPUS=8 so perhaps > the kernel has decided that this machine can possibly have eight CPUs. > > It's an old super-micro board, doesn't have ACPI. Well, it's looking like we only set

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Andrew Morton
On Mon, 24 Sep 2007 15:06:42 -0700 Dave Hansen <[EMAIL PROTECTED]> wrote: > On Sun, 2007-09-23 at 23:17 -0700, Andrew Morton wrote: > > It look like a false positive to me, but really, for a patchset of this > > complexity and maturity I cannot fathom how it could have escaped any > > lockdep

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Dave Hansen
On Sun, 2007-09-23 at 23:17 -0700, Andrew Morton wrote: > It look like a false positive to me, but really, for a patchset of this > complexity and maturity I cannot fathom how it could have escaped any > lockdep testing. I test with lockdep all the time. The problem was that lockdep doesn't

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Andrew Morton
On Mon, 24 Sep 2007 12:28:11 -0700 Dave Hansen <[EMAIL PROTECTED]> wrote: > On Mon, 2007-09-24 at 18:54 +0100, Christoph Hellwig wrote: > > As we already say in various messages the percpu counters in here > > look rather fishy. I'd recomment to take a look at the per-cpu > > superblock counters

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Dave Hansen
On Mon, 2007-09-24 at 18:54 +0100, Christoph Hellwig wrote: > As we already say in various messages the percpu counters in here > look rather fishy. I'd recomment to take a look at the per-cpu > superblock counters in XFS as they've been debugged quite well > now and could probably be lifted into

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Christoph Hellwig
On Mon, Sep 24, 2007 at 12:10:35PM -0700, Andrew Morton wrote: > > As we already say in various messages the percpu counters in here > > look rather fishy. I'd recomment to take a look at the per-cpu > > superblock counters in XFS as they've been debugged quite well > > now and could probably be

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Andrew Morton
On Mon, 24 Sep 2007 18:54:11 +0100 Christoph Hellwig <[EMAIL PROTECTED]> wrote: > As we already say in various messages the percpu counters in here > look rather fishy. I'd recomment to take a look at the per-cpu > superblock counters in XFS as they've been debugged quite well > now and could

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Christoph Hellwig
As we already say in various messages the percpu counters in here look rather fishy. I'd recomment to take a look at the per-cpu superblock counters in XFS as they've been debugged quite well now and could probably be lifted into a generic library for this kind of think. The code is mostly in

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Arjan van de Ven
> It look like a false positive to me, but really, for a patchset of > this complexity and maturity I cannot fathom how it could have > escaped any lockdep testing. the code tries to implement per cpu spinlocks, or rather it tries to bring back the brlocks from way past cute. we can educate

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Andrew Morton
On Thu, 20 Sep 2007 12:53:20 -0700 Dave Hansen <[EMAIL PROTECTED]> wrote: > This is the real meat of the entire series. It actually > implements the tracking of the number of writers to a mount. > However, it causes scalability problems because there can > be hundreds of cpus doing

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Andrew Morton
On Thu, 20 Sep 2007 12:53:20 -0700 Dave Hansen [EMAIL PROTECTED] wrote: This is the real meat of the entire series. It actually implements the tracking of the number of writers to a mount. However, it causes scalability problems because there can be hundreds of cpus doing open()/close() on

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Arjan van de Ven
It look like a false positive to me, but really, for a patchset of this complexity and maturity I cannot fathom how it could have escaped any lockdep testing. the code tries to implement per cpu spinlocks, or rather it tries to bring back the brlocks from way past cute. we can educate

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Christoph Hellwig
As we already say in various messages the percpu counters in here look rather fishy. I'd recomment to take a look at the per-cpu superblock counters in XFS as they've been debugged quite well now and could probably be lifted into a generic library for this kind of think. The code is mostly in

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Andrew Morton
On Mon, 24 Sep 2007 18:54:11 +0100 Christoph Hellwig [EMAIL PROTECTED] wrote: As we already say in various messages the percpu counters in here look rather fishy. I'd recomment to take a look at the per-cpu superblock counters in XFS as they've been debugged quite well now and could probably

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Christoph Hellwig
On Mon, Sep 24, 2007 at 12:10:35PM -0700, Andrew Morton wrote: As we already say in various messages the percpu counters in here look rather fishy. I'd recomment to take a look at the per-cpu superblock counters in XFS as they've been debugged quite well now and could probably be lifted

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Andrew Morton
On Mon, 24 Sep 2007 12:28:11 -0700 Dave Hansen [EMAIL PROTECTED] wrote: On Mon, 2007-09-24 at 18:54 +0100, Christoph Hellwig wrote: As we already say in various messages the percpu counters in here look rather fishy. I'd recomment to take a look at the per-cpu superblock counters in XFS

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Dave Hansen
On Mon, 2007-09-24 at 18:54 +0100, Christoph Hellwig wrote: As we already say in various messages the percpu counters in here look rather fishy. I'd recomment to take a look at the per-cpu superblock counters in XFS as they've been debugged quite well now and could probably be lifted into a

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Dave Hansen
On Sun, 2007-09-23 at 23:17 -0700, Andrew Morton wrote: It look like a false positive to me, but really, for a patchset of this complexity and maturity I cannot fathom how it could have escaped any lockdep testing. I test with lockdep all the time. The problem was that lockdep doesn't

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Andrew Morton
On Mon, 24 Sep 2007 15:06:42 -0700 Dave Hansen [EMAIL PROTECTED] wrote: On Sun, 2007-09-23 at 23:17 -0700, Andrew Morton wrote: It look like a false positive to me, but really, for a patchset of this complexity and maturity I cannot fathom how it could have escaped any lockdep testing.

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Dave Hansen
On Mon, 2007-09-24 at 15:25 -0700, Andrew Morton wrote: hm. I saw that warning on my 2-way. It has CONFIG_NR_CPUS=8 so perhaps the kernel has decided that this machine can possibly have eight CPUs. It's an old super-micro board, doesn't have ACPI. Well, it's looking like we only set

Re: [PATCH 24/25] r/o bind mounts: track number of mount writers

2007-09-24 Thread Andrew Morton
On Mon, 24 Sep 2007 16:05:37 -0700 Dave Hansen [EMAIL PROTECTED] wrote: On Mon, 2007-09-24 at 15:25 -0700, Andrew Morton wrote: hm. I saw that warning on my 2-way. It has CONFIG_NR_CPUS=8 so perhaps the kernel has decided that this machine can possibly have eight CPUs. It's an old