Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> writes:
> On Mon, 20 Oct 2008 20:11:56 +0200 Jens Axboe <jens.axboe@xxxxxxxxxx> wrote:
>
>> +ssize_t generic_file_splice_write_file_nolock(struct pipe_inode_info *pipe,
>> + struct file *out, loff_t *ppos,
>> + size_t len, unsigned int flags)
>> +{
>> + struct address_space *mapping = out->f_mapping;
>> + struct inode *inode = mapping->host;
>> + struct splice_desc sd = {
>> + .total_len = len,
>> + .flags = flags,
>> + .pos = *ppos,
>> + .u.file = out,
>> + };
>> + ssize_t ret;
>> +
>> + mutex_lock(&pipe->inode->i_mutex);
>> + ret = __splice_from_pipe(pipe, &sd, pipe_to_file);
>> + mutex_unlock(&pipe->inode->i_mutex);
>> +
>> + if (ret > 0) {
>> + unsigned long nr_pages;
>> +
>> + *ppos += ret;
>> + nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
>> +
>> + if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) {
>> + int er;
>> +
>> + er = sync_page_range_nolock(inode, mapping, *ppos, ret);
>> + if (er)
>> + ret = er;
>> + }
>> + balance_dirty_pages_ratelimited_nr(mapping, nr_pages);
>> + }
>> +
>> + return ret;
>> +}
>> +EXPORT_SYMBOL(generic_file_splice_write_file_nolock);
>
> I don't think the balance_dirty_pages() is needed if we just did the
> sync_page_range().
I think so too, but I've done it in this way because all other writers
does it.
>
>
> But really it'd be better if the throttling happened down in
> pipe_to_file(), on a per-page basis. As it stands we can dirty an
> arbitrary number of pagecache pages without throttling. I think?
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
