Messages in this thread | | | Date | Mon, 23 Jun 2014 17:45:33 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v8 4/4] printk: allow increasing the ring buffer depending on the number of CPUs |
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On Tue, 24 Jun 2014 02:20:50 +0200 "Luis R. Rodriguez" <mcgrof@suse.com> wrote:
> On Mon, Jun 23, 2014 at 03:41:34PM -0700, Andrew Morton wrote: > > On Wed, 18 Jun 2014 13:45:37 -0700 "Luis R. Rodriguez" <mcgrof@do-not-panic.com> wrote: > > > > > ... > > > > > > If an increase is required the ring buffer is increased to > > > + the next power of 2 that can fit both the minimum kernel ring buffer > > > + (LOG_BUF_SHIFT) plus the additional worst case CPU contributions. > > > > > > ... > > > > > > + log_buf_len_update(cpu_extra + __LOG_BUF_LEN); > > > +} > > > > I'd have expected > > > > total_cpu_space = minimum-per-cpu-len * nr_possible_cpus; > > log_buf_len = max(__LOG_BUF_LEN, total_cpu_space) > > > > but here you added __LOG_BUF_LEN to total_cpu_space and I cannot work > > out why. > > . > > Ah, because its cpu_extra, not total_cpu_space that is being > computed, the goal was to see how much extra junk on the > worst case a CPU might contribute. The __LOG_BUF_LEN is the > default size, so we combine both.
Well... why? Isn't it simpler and more direct to say "I want at least 32k per CPU"?
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