Messages in this thread | | | From | (Eric W. Biederman) | Date | Mon, 11 Jun 2018 17:59:38 -0500 | Subject | Re: [PATCH] kexec: yield to scheduler when loading kimage segments |
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Jarrett Farnitano <jmf@amazon.com> writes:
> Without yielding while loading kimage segments, a large initrd > will block all other work on the CPU performing the load until > it is completed. For example loading an initrd of 200MB on a > low power single core system will lock up the system for a few > seconds. > > To increase system responsiveness to other tasks at that time, > call cond_resched() in both the crash kernel and normal kernel > segment loading loops.
I remember years ago something like this was proposed and there was a reason we did not include it. I don't remember what that reason is right now. But I am reluctant to ack this until I remember.
Is there a practical problem with unresponsiveness? You are talking an embedded machine and rarely are there people in front of embedded computers these days.
Eric
> Signed-off-by: Jarrett Farnitano <jmf@amazon.com> > --- > kernel/kexec_core.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c > index 5616755..8ee07d6 100644 > --- a/kernel/kexec_core.c > +++ b/kernel/kexec_core.c > @@ -783,6 +783,8 @@ static int kimage_load_normal_segment(struct kimage *image, > else > buf += mchunk; > mbytes -= mchunk; > + > + cond_resched(); > } > out: > return result; > @@ -847,6 +849,8 @@ static int kimage_load_crash_segment(struct kimage *image, > else > buf += mchunk; > mbytes -= mchunk; > + > + cond_resched(); > } > out: > return result;
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