On Sun, Oct 28, 2012 at 3:55 PM, Zheng Liu <gnehzuil.liu@xxxxxxxxx> wrote:
> Hi Zhiyong,
>
> On Thu, Oct 25, 2012 at 11:08:55PM +0800, zwu.kernel@xxxxxxxxx wrote:
> [snip]
>> @@ -199,6 +342,54 @@ err:
>> }
>>
>> /*
>> + * Main function to update access frequency from read/writepage(s) hooks
>> + */
>> +inline void hot_update_freqs(struct inode *inode, u64 start,
>> + u64 len, int rw)
>
> This function seems too big. So we really need to inline this function?
As Dave said in his comments, it will add a function call
overhead even when tracking is not enabled. a static inline function
will just result in no extra overhead other than the if
statement....
>
> Regards,
> Zheng
>
>> +{
>> + struct hot_info *root = inode->i_sb->s_hot_root;
>> + struct hot_inode_item *he;
>> + struct hot_range_item *hr;
>> + u32 cur, end;
>> +
>> + if (!root || (len == 0))
>> + return;
>> +
>> + he = hot_inode_item_find(root, inode->i_ino);
>> + if (IS_ERR(he)) {
>> + WARN_ON(1);
>> + return;
>> + }
>> +
>> + spin_lock(&he->hot_inode.lock);
>> + hot_freq_data_update(&he->hot_inode.hot_freq_data, rw);
>> + spin_unlock(&he->hot_inode.lock);
>> +
>> + /*
>> + * Align ranges on RANGE_SIZE boundary
>> + * to prevent proliferation of range structs
>> + */
>> + end = (start + len + RANGE_SIZE - 1) >> RANGE_BITS;
>> + for (cur = (start >> RANGE_BITS); cur < end; cur++) {
>> + hr = hot_range_item_find(he, cur);
>> + if (IS_ERR(hr)) {
>> + WARN_ON(1);
>> + hot_inode_item_put(he);
>> + return;
>> + }
>> +
>> + spin_lock(&hr->hot_range.lock);
>> + hot_freq_data_update(&hr->hot_range.hot_freq_data, rw);
>> + spin_unlock(&hr->hot_range.lock);
>> +
>> + hot_range_item_put(hr);
>> + }
>> +
>> + hot_inode_item_put(he);
>> +}
>> +EXPORT_SYMBOL_GPL(hot_update_freqs);
--
Regards,
Zhi Yong Wu
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