linux-kernel - Re: [PATCH] ceph: remove SLAB_MEM

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Date: Mon, 26 Feb 2024 10:42:27 +0800
From: Chengming Zhou <chengming.zhou@...ux.dev>
To: Xiubo Li <xiubli@...hat.com>, idryomov@...il.com, jlayton@...nel.org
Cc: ceph-devel@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-mm@...ck.org, vbabka@...e.cz, roman.gushchin@...ux.dev,
 Xiongwei.Song@...driver.com, Chengming Zhou <zhouchengming@...edance.com>
Subject: Re: [PATCH] ceph: remove SLAB_MEM_SPREAD flag usage

On 2024/2/26 09:43, Xiubo Li wrote:
> Hi Chengming,
> 
> Thanks for your patch.
> 
> BTW, could you share the link of the relevant patches to mark this a no-op ?
Update changelog to make it clearer:

The SLAB_MEM_SPREAD flag used to be implemented in SLAB, which was
removed as of v6.8-rc1, so it became a dead flag. And the series[1]
went on to mark it obsolete to avoid confusion for users. Here we
can just remove all its users, which has no functional change.

[1] https://lore.kernel.org/all/20240223-slab-cleanup-flags-v2-1-02f1753e8303@suse.cz/

Thanks!

> 
> Thanks
> 
> - Xiubo
> 
> On 2/24/24 21:47, chengming.zhou@...ux.dev wrote:
>> From: Chengming Zhou <zhouchengming@...edance.com>
>>
>> The SLAB_MEM_SPREAD flag is already a no-op as of 6.8-rc1, remove
>> its usage so we can delete it from slab. No functional change.
>>
>> Signed-off-by: Chengming Zhou <zhouchengming@...edance.com>
>> ---
>>   fs/ceph/super.c | 18 +++++++++---------
>>   1 file changed, 9 insertions(+), 9 deletions(-)
>>
>> diff --git a/fs/ceph/super.c b/fs/ceph/super.c
>> index 5ec102f6b1ac..4dcbbaa297f6 100644
>> --- a/fs/ceph/super.c
>> +++ b/fs/ceph/super.c
>> @@ -928,36 +928,36 @@ static int __init init_caches(void)
>>       ceph_inode_cachep = kmem_cache_create("ceph_inode_info",
>>                         sizeof(struct ceph_inode_info),
>>                         __alignof__(struct ceph_inode_info),
>> -                      SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
>> -                      SLAB_ACCOUNT, ceph_inode_init_once);
>> +                      SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
>> +                      ceph_inode_init_once);
>>       if (!ceph_inode_cachep)
>>           return -ENOMEM;
>>   -    ceph_cap_cachep = KMEM_CACHE(ceph_cap, SLAB_MEM_SPREAD);
>> +    ceph_cap_cachep = KMEM_CACHE(ceph_cap, 0);
>>       if (!ceph_cap_cachep)
>>           goto bad_cap;
>> -    ceph_cap_snap_cachep = KMEM_CACHE(ceph_cap_snap, SLAB_MEM_SPREAD);
>> +    ceph_cap_snap_cachep = KMEM_CACHE(ceph_cap_snap, 0);
>>       if (!ceph_cap_snap_cachep)
>>           goto bad_cap_snap;
>>       ceph_cap_flush_cachep = KMEM_CACHE(ceph_cap_flush,
>> -                       SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
>> +                       SLAB_RECLAIM_ACCOUNT);
>>       if (!ceph_cap_flush_cachep)
>>           goto bad_cap_flush;
>>         ceph_dentry_cachep = KMEM_CACHE(ceph_dentry_info,
>> -                    SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
>> +                    SLAB_RECLAIM_ACCOUNT);
>>       if (!ceph_dentry_cachep)
>>           goto bad_dentry;
>>   -    ceph_file_cachep = KMEM_CACHE(ceph_file_info, SLAB_MEM_SPREAD);
>> +    ceph_file_cachep = KMEM_CACHE(ceph_file_info, 0);
>>       if (!ceph_file_cachep)
>>           goto bad_file;
>>   -    ceph_dir_file_cachep = KMEM_CACHE(ceph_dir_file_info, SLAB_MEM_SPREAD);
>> +    ceph_dir_file_cachep = KMEM_CACHE(ceph_dir_file_info, 0);
>>       if (!ceph_dir_file_cachep)
>>           goto bad_dir_file;
>>   -    ceph_mds_request_cachep = KMEM_CACHE(ceph_mds_request, SLAB_MEM_SPREAD);
>> +    ceph_mds_request_cachep = KMEM_CACHE(ceph_mds_request, 0);
>>       if (!ceph_mds_request_cachep)
>>           goto bad_mds_req;
>>   
>