Re: [PATCH] ocfs2: Remove custom swap functions in favor of built-in sort swap

[Heming Zhao <heming.zhao@suse.com>]

On 8/19/24 10:41, Joseph Qi wrote:
> 
> On 8/18/24 7:36 PM, Heming Zhao wrote:
>> On 8/11/24 03:53, Kuan-Wei Chiu wrote:
>>> The custom swap functions used in ocfs2 do not perform any special
>>> operations and can be replaced with the built-in swap function of sort.
>>> This change not only reduces code size but also improves efficiency,
>>> especially in scenarios where CONFIG_RETPOLINE is enabled, as it makes
>>> indirect function calls more expensive.
>>>
>>> By using the built-in swap, we avoid these costly indirect function
>>> calls, leading to better performance.
>>>
>>> Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
>>
>> Looks good to me
>> Signed-off-by: Heming Zhao <heming.zhao@suse.com>

Sorry for my mistake, above tag should be:
Reviewed-by: Heming Zhao <heming.zhao@suse.com>

>>
> 
> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
> 
>>> ---
>>> Note: Build test only.
>>>
>>>    fs/ocfs2/dir.c          | 12 +-----------
>>>    fs/ocfs2/refcounttree.c | 13 +++----------
>>>    fs/ocfs2/xattr.c        | 15 +++------------
>>>    3 files changed, 7 insertions(+), 33 deletions(-)
>>>
>>> diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
>>> index f0beb173dbba..fa5d0819a997 100644
>>> --- a/fs/ocfs2/dir.c
>>> +++ b/fs/ocfs2/dir.c
>>> @@ -3511,16 +3511,6 @@ static int dx_leaf_sort_cmp(const void *a, const void *b)
>>>        return 0;
>>>    }
>>>    -static void dx_leaf_sort_swap(void *a, void *b, int size)
>>> -{
>>> -    struct ocfs2_dx_entry *entry1 = a;
>>> -    struct ocfs2_dx_entry *entry2 = b;
>>> -
>>> -    BUG_ON(size != sizeof(*entry1));
>>> -
>>> -    swap(*entry1, *entry2);
>>> -}
>>> -
>>>    static int ocfs2_dx_leaf_same_major(struct ocfs2_dx_leaf *dx_leaf)
>>>    {
>>>        struct ocfs2_dx_entry_list *dl_list = &dx_leaf->dl_list;
>>> @@ -3781,7 +3771,7 @@ static int ocfs2_dx_dir_rebalance(struct ocfs2_super *osb, struct inode *dir,
>>>         */
>>>        sort(dx_leaf->dl_list.de_entries, num_used,
>>>             sizeof(struct ocfs2_dx_entry), dx_leaf_sort_cmp,
>>> -         dx_leaf_sort_swap);
>>> +         NULL);
>>>          ocfs2_journal_dirty(handle, dx_leaf_bh);
>>>    diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
>>> index 1f303b1adf1a..4f85508538fc 100644
>>> --- a/fs/ocfs2/refcounttree.c
>>> +++ b/fs/ocfs2/refcounttree.c
>>> @@ -1392,13 +1392,6 @@ static int cmp_refcount_rec_by_cpos(const void *a, const void *b)
>>>        return 0;
>>>    }
>>>    -static void swap_refcount_rec(void *a, void *b, int size)
>>> -{
>>> -    struct ocfs2_refcount_rec *l = a, *r = b;
>>> -
>>> -    swap(*l, *r);
>>> -}
>>> -
>>>    /*
>>>     * The refcount cpos are ordered by their 64bit cpos,
>>>     * But we will use the low 32 bit to be the e_cpos in the b-tree.
>>> @@ -1474,7 +1467,7 @@ static int ocfs2_divide_leaf_refcount_block(struct buffer_head *ref_leaf_bh,
>>>         */
>>>        sort(&rl->rl_recs, le16_to_cpu(rl->rl_used),
>>>             sizeof(struct ocfs2_refcount_rec),
>>> -         cmp_refcount_rec_by_low_cpos, swap_refcount_rec);
>>> +         cmp_refcount_rec_by_low_cpos, NULL);
>>>          ret = ocfs2_find_refcount_split_pos(rl, &cpos, &split_index);
>>>        if (ret) {
>>> @@ -1499,11 +1492,11 @@ static int ocfs2_divide_leaf_refcount_block(struct buffer_head *ref_leaf_bh,
>>>          sort(&rl->rl_recs, le16_to_cpu(rl->rl_used),
>>>             sizeof(struct ocfs2_refcount_rec),
>>> -         cmp_refcount_rec_by_cpos, swap_refcount_rec);
>>> +         cmp_refcount_rec_by_cpos, NULL);
>>>          sort(&new_rl->rl_recs, le16_to_cpu(new_rl->rl_used),
>>>             sizeof(struct ocfs2_refcount_rec),
>>> -         cmp_refcount_rec_by_cpos, swap_refcount_rec);
>>> +         cmp_refcount_rec_by_cpos, NULL);
>>>          *split_cpos = cpos;
>>>        return 0;
>>> diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
>>> index 35c0cc2a51af..0e58a5ce539e 100644
>>> --- a/fs/ocfs2/xattr.c
>>> +++ b/fs/ocfs2/xattr.c
>>> @@ -4167,15 +4167,6 @@ static int cmp_xe(const void *a, const void *b)
>>>        return 0;
>>>    }
>>>    -static void swap_xe(void *a, void *b, int size)
>>> -{
>>> -    struct ocfs2_xattr_entry *l = a, *r = b, tmp;
>>> -
>>> -    tmp = *l;
>>> -    memcpy(l, r, sizeof(struct ocfs2_xattr_entry));
>>> -    memcpy(r, &tmp, sizeof(struct ocfs2_xattr_entry));
>>> -}
>>> -
>>>    /*
>>>     * When the ocfs2_xattr_block is filled up, new bucket will be created
>>>     * and all the xattr entries will be moved to the new bucket.
>>> @@ -4241,7 +4232,7 @@ static void ocfs2_cp_xattr_block_to_bucket(struct inode *inode,
>>>        trace_ocfs2_cp_xattr_block_to_bucket_end(offset, size, off_change);
>>>          sort(target + offset, count, sizeof(struct ocfs2_xattr_entry),
>>> -         cmp_xe, swap_xe);
>>> +         cmp_xe, NULL);
>>>    }
>>>      /*
>>> @@ -4436,7 +4427,7 @@ static int ocfs2_defrag_xattr_bucket(struct inode *inode,
>>>         */
>>>        sort(entries, le16_to_cpu(xh->xh_count),
>>>             sizeof(struct ocfs2_xattr_entry),
>>> -         cmp_xe_offset, swap_xe);
>>> +         cmp_xe_offset, NULL);
>>>          /* Move all name/values to the end of the bucket. */
>>>        xe = xh->xh_entries;
>>> @@ -4478,7 +4469,7 @@ static int ocfs2_defrag_xattr_bucket(struct inode *inode,
>>>        /* sort the entries by their name_hash. */
>>>        sort(entries, le16_to_cpu(xh->xh_count),
>>>             sizeof(struct ocfs2_xattr_entry),
>>> -         cmp_xe, swap_xe);
>>> +         cmp_xe, NULL);
>>>          buf = bucket_buf;
>>>        for (i = 0; i < bucket->bu_blocks; i++, buf += blocksize)