Re: [PATCH 1/3] mm: page_alloc: Reduce object size by neatening printks

From: Joe Perches
Date: Thu Mar 16 2017 - 14:38:14 EST


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.

> just a notice. up to MM people to decide.