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

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Date: Mon, 26 Feb 2024 12:54:10 +0800
From: Xiubo Li <xiubli@...hat.com>
To: Chengming Zhou <chengming.zhou@...ux.dev>, 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 2/26/24 12:30, Chengming Zhou wrote:
> On 2024/2/26 12:23, Xiubo Li wrote:
>> On 2/26/24 10:42, Chengming Zhou wrote:
>>> 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 for your quick feedback.
>>
>> BTW, I couldn't find this change in Linus' tree in the master and even the v6.8-rc1 tag, please see https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/include/linux/slab.h?h=master.
>>
>> Did I miss something ? Or has this patch been merged ?
> You're right, this patch hasn't been merged. But it's already a dead flag as of v6.8-rc1.
>
> 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 since the commit
> 16a1d968358a ("mm/slab: remove mm/slab.c and slab_def.h"). 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/
>
> Does this look clearer to you? I can improve it if there is still confusion.

Yeah, much clearer, thanks!

Maybe we should just wait for the [1] to get merged first ?

Ilya, what do you think ?

Thanks

- Xiubo


> Thanks!
>
>> - Xiubo
>>
>>> 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;
>>>>>