> On Jan 25, 2021, at 8:36 PM, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
>
>
> For Subject: s/readpage/readpages/
>
> On Mon, Jan 25, 2021 at 09:37:29PM +0000, David Howells wrote:
>> +int __nfs_readahead_from_fscache(struct nfs_readdesc *desc,
>> + struct readahead_control *rac)
>
> I thought you wanted it called ractl instead of rac? That's what I've
> been using in new code.
>
>> - dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n",
>> - nfs_i_fscache(inode), npages, inode);
>> + dfprintk(FSCACHE, "NFS: nfs_readahead_from_fscache (0x%p/0x%p)\n",
>> + nfs_i_fscache(inode), inode);
>
> We do have readahead_count() if this is useful information to be logging.
As a sidebar, the Linux NFS community is transitioning to tracepoints.
It would be helpful (but not completely necessary) to use tracepoints
in new code instead of printk.
>> +static inline int nfs_readahead_from_fscache(struct nfs_readdesc *desc,
>> + struct readahead_control *rac)
>> {
>> - if (NFS_I(inode)->fscache)
>> - return __nfs_readpages_from_fscache(ctx, inode, mapping, pages,
>> - nr_pages);
>> + if (NFS_I(rac->mapping->host)->fscache)
>> + return __nfs_readahead_from_fscache(desc, rac);
>> return -ENOBUFS;
>> }
>
> Not entirely sure that it's worth having the two functions separated any more.
>
>> /* attempt to read as many of the pages as possible from the cache
>> * - this returns -ENOBUFS immediately if the cookie is negative
>> */
>> - ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping,
>> - pages, &nr_pages);
>> + ret = nfs_readahead_from_fscache(&desc, rac);
>> if (ret == 0)
>> goto read_complete; /* all pages were read */
>>
>> nfs_pageio_init_read(&desc.pgio, inode, false,
>> &nfs_async_read_completion_ops);
>>
>> - ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
>> + while ((page = readahead_page(rac))) {
>> + ret = readpage_async_filler(&desc, page);
>> + put_page(page);
>> + }
>
> I thought with the new API we didn't need to do this kind of thing
> any more? ie no matter whether fscache is configured in or not, it'll
> submit the I/Os.
--
Chuck Lever
