From 11d03d0a1ed8dbdabab1b5ab21861ad5cad4aef2 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Sat, 19 Feb 2022 19:09:21 -0500 Subject: [PATCH] NFS: Trace effects of the readdirplus heuristic Enable tracking of when the readdirplus heuristic causes a page cache invalidation. Signed-off-by: Trond Myklebust --- fs/nfs/dir.c | 11 ++++++++++- fs/nfs/nfstrace.h | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 60 insertions(+), 1 deletion(-) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 8b25a39..8a246df 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -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 diff --git a/fs/nfs/nfstrace.h b/fs/nfs/nfstrace.h index 7c1102b..ec2645d 100644 --- a/fs/nfs/nfstrace.h +++ b/fs/nfs/nfstrace.h @@ -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, -- 2.7.4