Commit 11d03d0a authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Trace effects of the readdirplus heuristic 



Enable tracking of when the readdirplus heuristic causes a page cache
invalidation.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent eace45a1

fs/nfs/dir.c

+10 −1
Original line number Diff line number Diff line
@@ -1000,6 +1000,8 @@ static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc) 
			if (res == -EBADCOOKIE || res == -ENOTSYNC) {

				invalidate_inode_pages2(desc->file->f_mapping);

				desc->page_index = 0;

				trace_nfs_readdir_invalidate_cache_range(

					inode, 0, MAX_LFS_FILESIZE);

				return -EAGAIN;

			}

			return res;
@@ -1014,6 +1016,9 @@ static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc) 
			invalidate_inode_pages2_range(desc->file->f_mapping,

						      desc->page_index_max + 1,

						      -1);

			trace_nfs_readdir_invalidate_cache_range(

				inode, desc->page_index_max + 1,

				MAX_LFS_FILESIZE);

		}

	}

	res = nfs_readdir_search_array(desc);
@@ -1163,7 +1168,11 @@ static void nfs_readdir_handle_cache_misses(struct inode *inode, 
	if (desc->ctx->pos == 0 ||

	    cache_misses <= NFS_READDIR_CACHE_MISS_THRESHOLD)

		return;

	invalidate_mapping_pages(inode->i_mapping, page_index + 1, -1);

	if (invalidate_mapping_pages(inode->i_mapping, page_index + 1, -1) == 0)

		return;

	trace_nfs_readdir_invalidate_cache_range(

		inode, (loff_t)(page_index + 1) << PAGE_SHIFT,

		MAX_LFS_FILESIZE);

}



/* The file offset position represents the dirent entry number.  A

fs/nfs/nfstrace.h

+50 −0
Original line number Diff line number Diff line
@@ -273,6 +273,56 @@ DEFINE_NFS_UPDATE_SIZE_EVENT(wcc); 
DEFINE_NFS_UPDATE_SIZE_EVENT(update);

DEFINE_NFS_UPDATE_SIZE_EVENT(grow);



DECLARE_EVENT_CLASS(nfs_inode_range_event,

		TP_PROTO(

			const struct inode *inode,

			loff_t range_start,

			loff_t range_end

		),



		TP_ARGS(inode, range_start, range_end),



		TP_STRUCT__entry(

			__field(dev_t, dev)

			__field(u32, fhandle)

			__field(u64, fileid)

			__field(u64, version)

			__field(loff_t, range_start)

			__field(loff_t, range_end)

		),



		TP_fast_assign(

			const struct nfs_inode *nfsi = NFS_I(inode);



			__entry->dev = inode->i_sb->s_dev;

			__entry->fhandle = nfs_fhandle_hash(&nfsi->fh);

			__entry->fileid = nfsi->fileid;

			__entry->version = inode_peek_iversion_raw(inode);

			__entry->range_start = range_start;

			__entry->range_end = range_end;

		),



		TP_printk(

			"fileid=%02x:%02x:%llu fhandle=0x%08x version=%llu "

			"range=[%lld, %lld]",

			MAJOR(__entry->dev), MINOR(__entry->dev),

			(unsigned long long)__entry->fileid,

			__entry->fhandle, __entry->version,

			__entry->range_start, __entry->range_end

		)

);



#define DEFINE_NFS_INODE_RANGE_EVENT(name) \

	DEFINE_EVENT(nfs_inode_range_event, name, \

			TP_PROTO( \

				const struct inode *inode, \

				loff_t range_start, \

				loff_t range_end \

			), \

			TP_ARGS(inode, range_start, range_end))



DEFINE_NFS_INODE_RANGE_EVENT(nfs_readdir_invalidate_cache_range);



DECLARE_EVENT_CLASS(nfs_readdir_event,

		TP_PROTO(

			const struct file *file,