> On Oct 7, 2021, at 7:32 PM, Dave Wysochanski <dwysocha@xxxxxxxxxx> wrote:
>
> Convert to the new VM readahead() API which is the preferred API
> to read multiple pages, and rename the NFSIOS_* counters and the
> tracepoint as needed.
>
> Signed-off-by: Dave Wysochanski <dwysocha@xxxxxxxxxx>
> ---
> fs/nfs/file.c | 2 +-
> fs/nfs/nfstrace.h | 2 +-
> fs/nfs/read.c | 21 +++++++++++++++------
> include/linux/nfs_fs.h | 3 +--
> include/linux/nfs_iostat.h | 6 +++---
> 5 files changed, 21 insertions(+), 13 deletions(-)
>
> diff --git a/fs/nfs/file.c b/fs/nfs/file.c
> index 209dac208477..cc76d17fa97f 100644
> --- a/fs/nfs/file.c
> +++ b/fs/nfs/file.c
> @@ -519,7 +519,7 @@ static void nfs_swap_deactivate(struct file *file)
>
> const struct address_space_operations nfs_file_aops = {
> .readpage = nfs_readpage,
> - .readpages = nfs_readpages,
> + .readahead = nfs_readahead,
> .set_page_dirty = __set_page_dirty_nobuffers,
> .writepage = nfs_writepage,
> .writepages = nfs_writepages,
> diff --git a/fs/nfs/nfstrace.h b/fs/nfs/nfstrace.h
> index 78b0f649dd09..d2b2080765a6 100644
> --- a/fs/nfs/nfstrace.h
> +++ b/fs/nfs/nfstrace.h
> @@ -915,7 +915,7 @@
> )
> );
>
> -TRACE_EVENT(nfs_aops_readpages,
> +TRACE_EVENT(nfs_aops_readahead,
In v2 and v3 of my patch, this tracepoint has already been
renamed to nfs_aop_readahead.
> TP_PROTO(
> const struct inode *inode,
> unsigned int nr_pages
> diff --git a/fs/nfs/read.c b/fs/nfs/read.c
> index 927504605e0f..5c2aab47cf1d 100644
> --- a/fs/nfs/read.c
> +++ b/fs/nfs/read.c
> @@ -395,15 +395,19 @@ int nfs_readpage(struct file *file, struct page *page)
> return ret;
> }
>
> -int nfs_readpages(struct file *file, struct address_space *mapping,
> - struct list_head *pages, unsigned nr_pages)
> +void nfs_readahead(struct readahead_control *ractl)
> {
> + struct file *file = ractl->file;
> + struct address_space *mapping = ractl->mapping;
> + struct page *page;
> + unsigned int nr_pages = readahead_count(ractl);
> +
> struct nfs_readdesc desc;
> struct inode *inode = mapping->host;
> int ret;
>
> - trace_nfs_aops_readpages(inode, nr_pages);
> - nfs_inc_stats(inode, NFSIOS_VFSREADPAGES);
> + trace_nfs_aops_readahead(inode, nr_pages);
> + nfs_inc_stats(inode, NFSIOS_VFSREADAHEAD);
>
> ret = -ESTALE;
> if (NFS_STALE(inode))
> @@ -420,13 +424,18 @@ int nfs_readpages(struct file *file, struct address_space *mapping,
> nfs_pageio_init_read(&desc.pgio, inode, false,
> &nfs_async_read_completion_ops);
>
> - ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
> + ret = 0;
> + while (!ret && (page = readahead_page(ractl))) {
> + prefetchw(&page->flags);
> + ret = readpage_async_filler(&desc, page);
> + put_page(page);
> + }
>
> nfs_pageio_complete_read(&desc.pgio);
>
> put_nfs_open_context(desc.ctx);
> out:
> - return ret;
> + return;
> }
>
> int __init nfs_init_readpagecache(void)
> diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
> index b9a8b925db43..6cbe3f2c5669 100644
> --- a/include/linux/nfs_fs.h
> +++ b/include/linux/nfs_fs.h
> @@ -580,8 +580,7 @@ extern int nfs_access_get_cached(struct inode *inode, const struct cred *cred, s
> * linux/fs/nfs/read.c
> */
> extern int nfs_readpage(struct file *, struct page *);
> -extern int nfs_readpages(struct file *, struct address_space *,
> - struct list_head *, unsigned);
> +extern void nfs_readahead(struct readahead_control *);
>
> /*
> * inline functions
> diff --git a/include/linux/nfs_iostat.h b/include/linux/nfs_iostat.h
> index 027874c36c88..418145f23700 100644
> --- a/include/linux/nfs_iostat.h
> +++ b/include/linux/nfs_iostat.h
> @@ -22,7 +22,7 @@
> #ifndef _LINUX_NFS_IOSTAT
> #define _LINUX_NFS_IOSTAT
>
> -#define NFS_IOSTAT_VERS "1.1"
> +#define NFS_IOSTAT_VERS "1.2"
>
> /*
> * NFS byte counters
> @@ -53,7 +53,7 @@
> * NFS page counters
> *
> * These count the number of pages read or written via nfs_readpage(),
> - * nfs_readpages(), or their write equivalents.
> + * nfs_readahead(), or their write equivalents.
> *
> * NB: When adding new byte counters, please include the measured
> * units in the name of each byte counter to help users of this
> @@ -98,7 +98,7 @@ enum nfs_stat_eventcounters {
> NFSIOS_VFSACCESS,
> NFSIOS_VFSUPDATEPAGE,
> NFSIOS_VFSREADPAGE,
> - NFSIOS_VFSREADPAGES,
> + NFSIOS_VFSREADAHEAD,
I'm wondering if you should add NFSIOS_VFSREADAHEAD
but leave NFSIOS_VFSREADPAGES? I don't remember exactly
how the mountstats API versioning is supposed to work.
> NFSIOS_VFSWRITEPAGE,
> NFSIOS_VFSWRITEPAGES,
> NFSIOS_VFSGETDENTS,
> --
> 1.8.3.1
>
--
Chuck Lever
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