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NFS: Trace effects of the readdirplus heuristic

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

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Trond Myklebust 2022-02-19 19:09:21 -05:00
parent eace45a18c
commit 11d03d0a1e
2 changed files with 60 additions and 1 deletions

11
fs/nfs/dir.c
View File

@ -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

50
fs/nfs/nfstrace.h
View File

@ -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,