Re: [PATCH v4 -next 08/15] mm: nommu: move sysctl to mm/nommu.c

On 2025/1/2 22:09, Lorenzo Stoakes wrote:
> On Mon, Dec 23, 2024 at 10:15:27PM +0800, Kaixiong Yu wrote:
>> The sysctl_nr_trim_pages belongs to nommu.c, move it to mm/nommu.c
>> from /kernel/sysctl.c. And remove the useless extern variable declaration
>> from include/linux/mm.h
>>
>> Signed-off-by: Kaixiong Yu <[email protected]>
> Looks good to me,
>
> Reviewed-by: Lorenzo Stoakes <[email protected]>
Thanks for your review !

Best ...
>> ---
>> v4:
>>   - const qualify struct ctl_table nommu_table
>> v3:
>>   - change the title
>> v2:
>>   - fix the build error: expected ';' after top level declarator
>>   - fix the build error: call to undeclared function 'register_syscall_init',
>>     use 'register_sysctl_init' to replace it.
>> ---
>> ---
>>   include/linux/mm.h |  2 --
>>   kernel/sysctl.c    | 10 ----------
>>   mm/nommu.c         | 15 ++++++++++++++-
>>   3 files changed, 14 insertions(+), 13 deletions(-)
>>
>> diff --git a/include/linux/mm.h b/include/linux/mm.h
>> index b3b87c1dc1e4..9813b5b9c093 100644
>> --- a/include/linux/mm.h
>> +++ b/include/linux/mm.h
>> @@ -4080,8 +4080,6 @@ unsigned long wp_shared_mapping_range(struct address_space *mapping,
>>   				      pgoff_t first_index, pgoff_t nr);
>>   #endif
>>
>> -extern int sysctl_nr_trim_pages;
>> -
>>   #ifdef CONFIG_PRINTK
>>   void mem_dump_obj(void *object);
>>   #else
>> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
>> index 62a58e417c40..97f9abffff0f 100644
>> --- a/kernel/sysctl.c
>> +++ b/kernel/sysctl.c
>> @@ -2031,16 +2031,6 @@ static struct ctl_table vm_table[] = {
>>   		.extra1		= SYSCTL_ONE,
>>   		.extra2		= SYSCTL_FOUR,
>>   	},
>> -#ifndef CONFIG_MMU
>> -	{
>> -		.procname	= "nr_trim_pages",
>> -		.data		= &sysctl_nr_trim_pages,
>> -		.maxlen		= sizeof(sysctl_nr_trim_pages),
>> -		.mode		= 0644,
>> -		.proc_handler	= proc_dointvec_minmax,
>> -		.extra1		= SYSCTL_ZERO,
>> -	},
>> -#endif
> Of course later on in the series you do what I asked in a previous commit :P Nice.
>
>>   	{
>>   		.procname	= "vfs_cache_pressure",
>>   		.data		= &sysctl_vfs_cache_pressure,
>> diff --git a/mm/nommu.c b/mm/nommu.c
>> index baa79abdaf03..3c32f8b1eb54 100644
>> --- a/mm/nommu.c
>> +++ b/mm/nommu.c
>> @@ -48,7 +48,6 @@ struct page *mem_map;
>>   unsigned long max_mapnr;
>>   EXPORT_SYMBOL(max_mapnr);
>>   unsigned long highest_memmap_pfn;
>> -int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
>>   int heap_stack_gap = 0;
>>
>>   atomic_long_t mmap_pages_allocated;
>> @@ -392,6 +391,19 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
>>   	return mm->brk = brk;
>>   }
>>
>> +static int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
>> +
>> +static const struct ctl_table nommu_table[] = {
>> +	{
>> +		.procname	= "nr_trim_pages",
>> +		.data		= &sysctl_nr_trim_pages,
>> +		.maxlen		= sizeof(sysctl_nr_trim_pages),
>> +		.mode		= 0644,
>> +		.proc_handler	= proc_dointvec_minmax,
>> +		.extra1		= SYSCTL_ZERO,
>> +	},
>> +};
>> +
>>   /*
>>    * initialise the percpu counter for VM and region record slabs
>>    */
>> @@ -402,6 +414,7 @@ void __init mmap_init(void)
>>   	ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
>>   	VM_BUG_ON(ret);
>>   	vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC|SLAB_ACCOUNT);
>> +	register_sysctl_init("vm", nommu_table);
>>   }
>>
>>   /*
>> --
>> 2.34.1
>>
> .
>