On Monday 22 February 2010, Alan Jenkins wrote:
> Rafael J. Wysocki wrote:
> > On Friday 19 February 2010, Alan Jenkins wrote:
> >
> >> On 2/18/10, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> >>
> >>> On Thursday 18 February 2010, Alan Jenkins wrote:
> >>>
> >>>> On 2/17/10, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> >>>>
> >>>>> On Wednesday 17 February 2010, Alan Jenkins wrote:
> >>>>>
> >>>>>> On 2/16/10, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> >>>>>>
> >>>>>>> On Tuesday 16 February 2010, Alan Jenkins wrote:
> >>>>>>>
> >>>>>>>> On 2/16/10, Alan Jenkins <sourcejedi.lkml@xxxxxxxxxxxxxx> wrote:
> >>>>>>>>
> >>>>>>>>> On 2/15/10, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> >>>>>>>>>
> >>>>>>>>>> On Tuesday 09 February 2010, Alan Jenkins wrote:
> >>>>>>>>>>
> >>>>>>>>>>> Perhaps I spoke too soon. I see the same hang if I run too many
> >>>>>>>>>>> applications. The first hibernation fails with "not enough
> >>>>>>>>>>> swap"
> >>>>>>>>>>> as
> >>>>>>>>>>> expected, but the second or third attempt hangs (with the same
> >>>>>>>>>>> backtrace
> >>>>>>>>>>> as before).
> >>>>>>>>>>>
> >>>>>>>>>>> The patch definitely helps though. Without the patch, I see a
> >>>>>>>>>>> hang
> >>>>>>>>>>> the
> >>>>>>>>>>> first time I try to hibernate with too many applications
> >>>>>>>>>>> running.
> >>>>>>>>>>>
> >>>>>>>>>> Well, I have an idea.
> >>>>>>>>>>
> >>>>>>>>>> Can you try to apply the appended patch in addition and see if
> >>>>>>>>>> that
> >>>>>>>>>> helps?
> >>>>>>>>>>
> >>>>>>>>>> Rafael
> >>>>>>>>>>
> >>>>>>>>> It doesn't seem to help.
> >>>>>>>>>
> >>>>>>>> To be clear: It doesn't stop the hang when I hibernate with too many
> >>>>>>>> applications.
> >>>>>>>>
> >>>>>>>> It does stop the same hang in a different case though.
> >>>>>>>>
> >>>>>>>> 1. boot with init=/bin/bash
> >>>>>>>> 2. run s2disk
> >>>>>>>> 3. cancel the s2disk
> >>>>>>>> 4. repeat steps 2&3
> >>>>>>>>
> >>>>>>>> With the patch, I can run 10s of iterations, with no hang.
> >>>>>>>> Without the patch, it soon hangs, (in disable_nonboot_cpus(), as
> >>>>>>>> always).
> >>>>>>>>
> >>>>>>>> That's what happens on 2.6.33-rc7. On 2.6.30, there is no problem.
> >>>>>>>> On 2.6.31 and 2.6.32 I don't get a hang, but dmesg shows an
> >>>>>>>> allocation
> >>>>>>>> failure after a couple of iterations ("kthreadd: page allocation
> >>>>>>>> failure. order:1, mode:0xd0"). It looks like it might be the same
> >>>>>>>> stop_machine thread allocation failure that causes the hang.
> >>>>>>>>
> >>>>>>> Have you tested it alone or on top of the previous one? If you've
> >>>>>>> tested it
> >>>>>>> alone, please apply the appended one in addition to it and retest.
> >>>>>>>
> >>>>>>> Rafael
> >>>>>>>
> >>>>>> I did test with both patches applied together -
> >>>>>>
> >>>>>> 1. [Update] MM / PM: Force GFP_NOIO during suspend/hibernation and
> >>>>>> resume
> >>>>>> 2. "reducing the number of pages that we're going to keep preallocated
> >>>>>> by
> >>>>>> 20%"
> >>>>>>
> >>>>> In that case you can try to reduce the number of preallocated pages even
> >>>>> more,
> >>>>> ie. change "/ 5" to "/ 2" (for example) in the second patch.
> >>>>>
> >>>> It still hangs if I try to hibernate a couple of times with too many
> >>>> applications.
> >>>>
> >>> Hmm. I guess I asked that before, but is this a 32-bit or 64-bit system and
> >>> how much RAM is there in the box?
> >>>
> >>> Rafael
> >>>
> >> EeePC 701. 32 bit. 512Mb RAM. 350Mb swap file, on a "first-gen" SSD.
> >>
> >
> > Hmm. I'd try to make free_unnecessary_pages() free all of the preallocated
> > pages and see what happens.
> >
>
> It still hangs in hibernation_snapshot() / disable_nonboot_cpus().
> After apparently freeing over 400Mb / 100,000 pages of preallocated ram.
>
>
>
> There is a change which I missed before. When I applied your first
> patch ("Force GFP_NOIO during suspend" etc.), it did change the hung
> task backtraces a bit. I don't know if it tells us anything.
>
> Without the patch, there were two backtraces. The first backtrace
> suggested a problem allocating pages for a kernel thread (at
> copy_process() / try_to_free_pages()). The second showed that this
> problem was blocking s2disk (at hibernation_snapshot() /
> disable_nonboot_cpus() / stop_machine_create()).
>
> With the GFP_NOIO patch, I see only the s2disk backtrace.
Can you please post this backtrace?
Rafael
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