nfs/localio: add tracepoints for misaligned DIO READ and WRITE support

Add nfs_local_dio_class and use it to create nfs_local_dio_read,
nfs_local_dio_write and nfs_local_dio_misaligned trace events.

These trace events show how NFS LOCALIO splits a given misaligned
IO into a mix of misaligned head and/or tail extents and a DIO-aligned
middle extent.  The misaligned head and/or tail extents are issued
using buffered IO and the DIO-aligned middle is issued using O_DIRECT.

This combination of trace events is useful for LOCALIO DIO READs:

  echo 1 > /sys/kernel/tracing/events/nfs/nfs_local_dio_read/enable
  echo 1 > /sys/kernel/tracing/events/nfs/nfs_local_dio_misaligned/enable
  echo 1 > /sys/kernel/tracing/events/nfs/nfs_initiate_read/enable
  echo 1 > /sys/kernel/tracing/events/nfs/nfs_readpage_done/enable
  echo 1 > /sys/kernel/tracing/events/xfs/xfs_file_direct_read/enable

This combination of trace events is useful for LOCALIO DIO WRITEs:

  echo 1 > /sys/kernel/tracing/events/nfs/nfs_local_dio_write/enable
  echo 1 > /sys/kernel/tracing/events/nfs/nfs_local_dio_misaligned/enable
  echo 1 > /sys/kernel/tracing/events/nfs/nfs_initiate_write/enable
  echo 1 > /sys/kernel/tracing/events/nfs/nfs_writeback_done/enable
  echo 1 > /sys/kernel/tracing/events/xfs/xfs_file_direct_write/enable

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index c0a44f389f8f42ba5fb9149f0278e566a00542bb..2ecd38e1d17a8053a9134702588d57efc35f49e9 100644 (file)
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -456,6 +456,16 @@ extern int nfs_wait_bit_killable(struct wait_bit_key *key, int mode);
 
 #if IS_ENABLED(CONFIG_NFS_LOCALIO)
 /* localio.c */
+struct nfs_local_dio {
+       u32 mem_align;
+       u32 offset_align;
+       loff_t middle_offset;
+       loff_t end_offset;
+       ssize_t start_len;      /* Length for misaligned first extent */
+       ssize_t middle_len;     /* Length for DIO-aligned middle extent */
+       ssize_t end_len;        /* Length for misaligned last extent */
+};
+
 extern void nfs_local_probe_async(struct nfs_client *);
 extern void nfs_local_probe_async_work(struct work_struct *);
 extern struct nfsd_file *nfs_local_open_fh(struct nfs_client *,

diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c
index 8978e1ad4bc94c5de96ef334450908db7a1db6c5..b575f0e6c7c8e1294946e79ee1614a958bca2c65 100644 (file)
--- a/fs/nfs/localio.c
+++ b/fs/nfs/localio.c
@@ -322,16 +322,6 @@ nfs_local_iocb_alloc(struct nfs_pgio_header *hdr,
        return iocb;
 }
 
-struct nfs_local_dio {
-       u32 mem_align;
-       u32 offset_align;
-       loff_t middle_offset;
-       loff_t end_offset;
-       ssize_t start_len;      /* Length for misaligned first extent */
-       ssize_t middle_len;     /* Length for DIO-aligned middle extent */
-       ssize_t end_len;        /* Length for misaligned last extent */
-};
-
 static bool
 nfs_is_local_dio_possible(struct nfs_local_kiocb *iocb, int rw,
                          size_t len, struct nfs_local_dio *local_dio)
@@ -367,6 +357,10 @@ nfs_is_local_dio_possible(struct nfs_local_kiocb *iocb, int rw,
        local_dio->middle_len = middle_end - start_end;
        local_dio->end_len = orig_end - middle_end;
 
+       if (rw == ITER_DEST)
+               trace_nfs_local_dio_read(hdr->inode, offset, len, local_dio);
+       else
+               trace_nfs_local_dio_write(hdr->inode, offset, len, local_dio);
        return true;
 }
 
@@ -446,8 +440,11 @@ nfs_local_iters_setup_dio(struct nfs_local_kiocb *iocb, int rw,
                nfs_iov_iter_aligned_bvec(&iters[n_iters],
                        local_dio->mem_align-1, local_dio->offset_align-1);
 
-       if (unlikely(!iocb->iter_is_dio_aligned[n_iters]))
+       if (unlikely(!iocb->iter_is_dio_aligned[n_iters])) {
+               trace_nfs_local_dio_misaligned(iocb->hdr->inode,
+                       iocb->hdr->args.offset, len, local_dio);
                return 0; /* no DIO-aligned IO possible */
+       }
        ++n_iters;
 
        iocb->n_iters = n_iters;

diff --git a/fs/nfs/nfs2xdr.c b/fs/nfs/nfs2xdr.c
index 6e75c6c2d2347ef8ebd0353de9960c7ef7bcecc2..9eff091585181fbbdc67a57ceb669abebf381f63 100644 (file)
--- a/fs/nfs/nfs2xdr.c
+++ b/fs/nfs/nfs2xdr.c
@@ -23,8 +23,8 @@
 #include <linux/nfs2.h>
 #include <linux/nfs_fs.h>
 #include <linux/nfs_common.h>
-#include "nfstrace.h"
 #include "internal.h"
+#include "nfstrace.h"
 
 #define NFSDBG_FACILITY                NFSDBG_XDR
 

diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
index 4ae01c10b7e284fff1fe5fc05452cfba7e9dcc8e..e17d7290841256613c422ee2b6c4b545f7e7092b 100644 (file)
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -23,8 +23,8 @@
 #include <linux/nfsacl.h>
 #include <linux/nfs_common.h>
 
-#include "nfstrace.h"
 #include "internal.h"
+#include "nfstrace.h"
 
 #define NFSDBG_FACILITY                NFSDBG_XDR
 

diff --git a/fs/nfs/nfstrace.h b/fs/nfs/nfstrace.h
index b51f0fa9e9afebac9a2d7497264e86a87f35982f..6ce55e8e6b67c0cc31f30a6b7d334133178fb818 100644 (file)
--- a/fs/nfs/nfstrace.h
+++ b/fs/nfs/nfstrace.h
@@ -1732,6 +1732,76 @@ DEFINE_NFS_DIRECT_REQ_EVENT(nfs_direct_write_completion);
 DEFINE_NFS_DIRECT_REQ_EVENT(nfs_direct_write_schedule_iovec);
 DEFINE_NFS_DIRECT_REQ_EVENT(nfs_direct_write_reschedule_io);
 
+#if IS_ENABLED(CONFIG_NFS_LOCALIO)
+
+DECLARE_EVENT_CLASS(nfs_local_dio_class,
+       TP_PROTO(
+               const struct inode *inode,
+               loff_t offset,
+               ssize_t count,
+               const struct nfs_local_dio *local_dio
+       ),
+       TP_ARGS(inode, offset, count, local_dio),
+       TP_STRUCT__entry(
+               __field(dev_t, dev)
+               __field(u64, fileid)
+               __field(u32, fhandle)
+               __field(loff_t, offset)
+               __field(ssize_t, count)
+               __field(u32, mem_align)
+               __field(u32, offset_align)
+               __field(loff_t, start)
+               __field(ssize_t, start_len)
+               __field(loff_t, middle)
+               __field(ssize_t, middle_len)
+               __field(loff_t, end)
+               __field(ssize_t, end_len)
+       ),
+       TP_fast_assign(
+               const struct nfs_inode *nfsi = NFS_I(inode);
+               const struct nfs_fh *fh = &nfsi->fh;
+
+               __entry->dev = inode->i_sb->s_dev;
+               __entry->fileid = nfsi->fileid;
+               __entry->fhandle = nfs_fhandle_hash(fh);
+               __entry->offset = offset;
+               __entry->count = count;
+               __entry->mem_align = local_dio->mem_align;
+               __entry->offset_align = local_dio->offset_align;
+               __entry->start = offset;
+               __entry->start_len = local_dio->start_len;
+               __entry->middle = local_dio->middle_offset;
+               __entry->middle_len = local_dio->middle_len;
+               __entry->end = local_dio->end_offset;
+               __entry->end_len = local_dio->end_len;
+       ),
+       TP_printk("fileid=%02x:%02x:%llu fhandle=0x%08x "
+                 "offset=%lld count=%zd "
+                 "mem_align=%u offset_align=%u "
+                 "start=%llu+%zd middle=%llu+%zd end=%llu+%zd",
+                 MAJOR(__entry->dev), MINOR(__entry->dev),
+                 (unsigned long long)__entry->fileid,
+                 __entry->fhandle, __entry->offset, __entry->count,
+                 __entry->mem_align, __entry->offset_align,
+                 __entry->start, __entry->start_len,
+                 __entry->middle, __entry->middle_len,
+                 __entry->end, __entry->end_len)
+)
+
+#define DEFINE_NFS_LOCAL_DIO_EVENT(name)               \
+DEFINE_EVENT(nfs_local_dio_class, nfs_local_dio_##name,        \
+       TP_PROTO(const struct inode *inode,             \
+                loff_t offset,                         \
+                ssize_t count,                         \
+                const struct nfs_local_dio *local_dio),\
+       TP_ARGS(inode, offset, count, local_dio))
+
+DEFINE_NFS_LOCAL_DIO_EVENT(read);
+DEFINE_NFS_LOCAL_DIO_EVENT(write);
+DEFINE_NFS_LOCAL_DIO_EVENT(misaligned);
+
+#endif /* CONFIG_NFS_LOCALIO */
+
 TRACE_EVENT(nfs_fh_to_dentry,
                TP_PROTO(
                        const struct super_block *sb,