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Groups > linux.kernel > #1602990
| From | Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 1/3] mm: page_alloc: Reduce object size by neatening printks |
| Date | 2017-03-17 03:10 +0100 |
| Message-ID | <tlPv3-7nQ-5@gated-at.bofh.it> (permalink) |
| References | <tlsI9-7Ou-3@gated-at.bofh.it> <tlsI9-7Ou-9@gated-at.bofh.it> <tlBV7-62w-1@gated-at.bofh.it> <tlItA-2iT-21@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On (03/16/17 11:37), Joe Perches wrote:
> On Thu, 2017-03-16 at 20:30 +0900, Sergey Senozhatsky wrote:
> > On (03/15/17 18:43), Joe Perches wrote:
> > [..]
> > > - printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
> > > - " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
> > > - " unevictable:%lu dirty:%lu writeback:%lu unstable:%lu\n"
> > > - " slab_reclaimable:%lu slab_unreclaimable:%lu\n"
> > > - " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
> > > - " free:%lu free_pcp:%lu free_cma:%lu\n",
> > > - global_node_page_state(NR_ACTIVE_ANON),
> > > - global_node_page_state(NR_INACTIVE_ANON),
> > > - global_node_page_state(NR_ISOLATED_ANON),
> > > - global_node_page_state(NR_ACTIVE_FILE),
> > > - global_node_page_state(NR_INACTIVE_FILE),
> > > - global_node_page_state(NR_ISOLATED_FILE),
> > > - global_node_page_state(NR_UNEVICTABLE),
> > > - global_node_page_state(NR_FILE_DIRTY),
> > > - global_node_page_state(NR_WRITEBACK),
> > > - global_node_page_state(NR_UNSTABLE_NFS),
> > > - global_page_state(NR_SLAB_RECLAIMABLE),
> > > - global_page_state(NR_SLAB_UNRECLAIMABLE),
> > > - global_node_page_state(NR_FILE_MAPPED),
> > > - global_node_page_state(NR_SHMEM),
> > > - global_page_state(NR_PAGETABLE),
> > > - global_page_state(NR_BOUNCE),
> > > - global_page_state(NR_FREE_PAGES),
> > > - free_pcp,
> > > - global_page_state(NR_FREE_CMA_PAGES));
> > > + printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n",
> > > + global_node_page_state(NR_ACTIVE_ANON),
> > > + global_node_page_state(NR_INACTIVE_ANON),
> > > + global_node_page_state(NR_ISOLATED_ANON));
> > > + printk("active_file:%lu inactive_file:%lu isolated_file:%lu\n",
> > > + global_node_page_state(NR_ACTIVE_FILE),
> > > + global_node_page_state(NR_INACTIVE_FILE),
> > > + global_node_page_state(NR_ISOLATED_FILE));
> > > + printk("unevictable:%lu dirty:%lu writeback:%lu unstable:%lu\n",
> > > + global_node_page_state(NR_UNEVICTABLE),
> > > + global_node_page_state(NR_FILE_DIRTY),
> > > + global_node_page_state(NR_WRITEBACK),
> > > + global_node_page_state(NR_UNSTABLE_NFS));
> > > + printk("slab_reclaimable:%lu slab_unreclaimable:%lu\n",
> > > + global_page_state(NR_SLAB_RECLAIMABLE),
> > > + global_page_state(NR_SLAB_UNRECLAIMABLE));
> > > + printk("mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n",
> > > + global_node_page_state(NR_FILE_MAPPED),
> > > + global_node_page_state(NR_SHMEM),
> > > + global_page_state(NR_PAGETABLE),
> > > + global_page_state(NR_BOUNCE));
> > > + printk("free:%lu free_pcp:%lu free_cma:%lu\n",
> > > + global_page_state(NR_FREE_PAGES),
> > > + free_pcp,
> > > + global_page_state(NR_FREE_CMA_PAGES));
> >
> > a side note:
> >
> > this can make it harder to read, in _the worst case_. one printk()
> > guaranteed that we would see a single line in the serial log/etc.
> > the sort of a problem with multiple printks is that printks coming
> > from other CPUs will split that "previously single" line.
>
> Not true. Note the multiple \n uses in the original code.
one printk call ends up in logbuf as a single entry and, thus, we print
it to the serial console in one shot (what is the correct english word
to use here?). multiple printks result in multiple logbuf entries, and
printks from other CPUs can mix in.
so the difference is:
CPU0 CPU1
printk(foo\n)
printk(..isolated_anon\n...isolated_file\n...)
printk(bar\n)
vs
CPU0 CPU1
printk(..isolated_anon\n)
printk(foo\n)
printk(...isolated_file\n)
printk(bar\n)
printk(...\n)
not the same thing.
and the slower the serial console is the more messages potentially
can appear between "..isolated_anon\n" and "...isolated_file\n".
-ss
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[PATCH 0/3] mm: page_alloc: Object code reductions and logging fix Joe Perches <joe@perches.com> - 2017-03-16 02:50 +0100
[PATCH 2/3] mm: page_alloc: Fix misordered logging output, reduce code size Joe Perches <joe@perches.com> - 2017-03-16 02:50 +0100
Re: [PATCH 2/3] mm: page_alloc: Fix misordered logging output, reduce code size Michal Hocko <mhocko@kernel.org> - 2017-03-16 12:00 +0100
[PATCH 1/3] mm: page_alloc: Reduce object size by neatening printks Joe Perches <joe@perches.com> - 2017-03-16 02:50 +0100
Re: [PATCH 1/3] mm: page_alloc: Reduce object size by neatening printks Michal Hocko <mhocko@kernel.org> - 2017-03-16 12:00 +0100
Re: [PATCH 1/3] mm: page_alloc: Reduce object size by neatening printks Joe Perches <joe@perches.com> - 2017-03-16 21:40 +0100
Re: [PATCH 1/3] mm: page_alloc: Reduce object size by neatening printks Michal Hocko <mhocko@kernel.org> - 2017-03-17 08:40 +0100
Re: [PATCH 1/3] mm: page_alloc: Reduce object size by neatening printks Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-03-16 12:40 +0100
Re: [PATCH 1/3] mm: page_alloc: Reduce object size by neatening printks Joe Perches <joe@perches.com> - 2017-03-16 19:40 +0100
Re: [PATCH 1/3] mm: page_alloc: Reduce object size by neatening printks Andrew Morton <akpm@linux-foundation.org> - 2017-03-17 00:00 +0100
Re: [PATCH 1/3] mm: page_alloc: Reduce object size by neatening printks Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-03-17 03:10 +0100
Re: [PATCH 1/3] mm: page_alloc: Reduce object size by neatening printks Joe Perches <joe@perches.com> - 2017-03-18 20:40 +0100
Re: [PATCH 1/3] mm: page_alloc: Reduce object size by neatening printks Petr Mladek <pmladek@suse.com> - 2017-03-20 14:30 +0100
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