On Mon 13-10-14 14:51:56, Dave Jones wrote: [...] > diff --git a/mm/debug.c b/mm/debug.c > index 5ce45c9a29b5..e04e2ae902a1 100644 > --- a/mm/debug.c > +++ b/mm/debug.c > @@ -164,74 +164,85 @@ void dump_vma(const struct vm_area_struct *vma) > } > EXPORT_SYMBOL(dump_vma); > > +static char dumpmm_buffer[4096]; > + > void dump_mm(const struct mm_struct *mm) > { > - pr_emerg("mm %p mmap %p seqnum %d task_size %lu\n" > -#ifdef CONFIG_MMU > - "get_unmapped_area %p\n" > -#endif > - "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n" > - "pgd %p mm_users %d mm_count %d nr_ptes %lu map_count %d\n" > - "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n" > - "pinned_vm %lx shared_vm %lx exec_vm %lx stack_vm %lx\n" > - "start_code %lx end_code %lx start_data %lx end_data %lx\n" > - "start_brk %lx brk %lx start_stack %lx\n" > - "arg_start %lx arg_end %lx env_start %lx env_end %lx\n" > - "binfmt %p flags %lx core_state %p\n" > -#ifdef CONFIG_AIO > - "ioctx_table %p\n" > -#endif > -#ifdef CONFIG_MEMCG > - "owner %p " > -#endif > - "exe_file %p\n" > -#ifdef CONFIG_MMU_NOTIFIER > - "mmu_notifier_mm %p\n" > -#endif > -#ifdef CONFIG_NUMA_BALANCING > - "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n" > -#endif > -#if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION) > - "tlb_flush_pending %d\n" > -#endif > - "%s", /* This is here to hold the comma */ > + char *p = dumpmm_buffer; > + > + memset(dumpmm_buffer, 0, 4096); I do not see any locking here. Previously we had internal printk log as a natural synchronization. Now two threads are allowed to scribble over their messages leaving an unusable output in a better case. Besides that the %s with "" trick is not really that ugly and handles the situation quite nicely. So do we really want to make it more complicated? -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>