On 2/5/21 1:33 PM, Kalesh Singh wrote: > And 'inode_no' field to /proc/<pid>/fdinfo/<FD> and > /proc/<pid>/task/<tid>/fdinfo/<FD>. > > The inode numbers can be used to uniquely identify DMA buffers > in user space and avoids a dependency on /proc/<pid>/fd/* when > accounting per-process DMA buffer sizes. > > Signed-off-by: Kalesh Singh <[email protected]> > --- > Changes in v4: > - Add inode number as common field in fdinfo, per Christian > Changes in v3: > - Add documentation in proc.rst, per Randy > Changes in v2: > - Update patch description > > Documentation/filesystems/proc.rst | 37 +++++++++++++++++++++++++----- > fs/proc/fd.c | 5 ++-- > 2 files changed, 34 insertions(+), 8 deletions(-) > > diff --git a/Documentation/filesystems/proc.rst > b/Documentation/filesystems/proc.rst > index 2fa69f710e2a..db46da32230c 100644 > --- a/Documentation/filesystems/proc.rst > +++ b/Documentation/filesystems/proc.rst > @@ -1902,18 +1902,20 @@ if precise results are needed. > 3.8 /proc/<pid>/fdinfo/<fd> - Information about opened file > --------------------------------------------------------------- > This file provides information associated with an opened file. The regular > -files have at least three fields -- 'pos', 'flags' and 'mnt_id'. The 'pos' > -represents the current offset of the opened file in decimal form [see > lseek(2) > -for details], 'flags' denotes the octal O_xxx mask the file has been > -created with [see open(2) for details] and 'mnt_id' represents mount ID of > -the file system containing the opened file [see 3.5 /proc/<pid>/mountinfo > -for details]. > +files have at least four fields -- 'pos', 'flags', 'mnt_id' and 'inode_no'. > +The 'pos' represents the current offset of the opened file in decimal > +form [see lseek(2) for details], 'flags' denotes the octal O_xxx mask the > +file has been created with [see open(2) for details] and 'mnt_id' represents > +mount ID of the file system containing the opened file [see 3.5 > +/proc/<pid>/mountinfo for details]. 'inode_no' represents the inode number > +of the file. > > A typical output is:: > > pos: 0 > flags: 0100002 > mnt_id: 19 > + inode_no: 63107 > > All locks associated with a file descriptor are shown in its fdinfo too:: > > @@ -1930,6 +1932,7 @@ Eventfd files > pos: 0 > flags: 04002 > mnt_id: 9 > + inode_no: 63107 > eventfd-count: 5a > > where 'eventfd-count' is hex value of a counter. > @@ -1942,6 +1945,7 @@ Signalfd files > pos: 0 > flags: 04002 > mnt_id: 9 > + inode_no: 63107 > sigmask: 0000000000000200 > > where 'sigmask' is hex value of the signal mask associated > @@ -1955,6 +1959,7 @@ Epoll files > pos: 0 > flags: 02 > mnt_id: 9 > + inode_no: 63107 > tfd: 5 events: 1d data: ffffffffffffffff pos:0 ino:61af > sdev:7 > > where 'tfd' is a target file descriptor number in decimal form, > @@ -1971,6 +1976,8 @@ For inotify files the format is the following:: > > pos: 0 > flags: 02000000 > + mnt_id: 9 > + inode_no: 63107 > inotify wd:3 ino:9e7e sdev:800013 mask:800afce ignored_mask:0 > fhandle-bytes:8 fhandle-type:1 f_handle:7e9e0000640d1b6d > > where 'wd' is a watch descriptor in decimal form, i.e. a target file > @@ -1993,6 +2000,7 @@ For fanotify files the format is:: > pos: 0 > flags: 02 > mnt_id: 9 > + inode_no: 63107 > fanotify flags:10 event-flags:0 > fanotify mnt_id:12 mflags:40 mask:38 ignored_mask:40000003 > fanotify ino:4f969 sdev:800013 mflags:0 mask:3b ignored_mask:40000000 > fhandle-bytes:8 fhandle-type:1 f_handle:69f90400c275b5b4 > @@ -2017,6 +2025,7 @@ Timerfd files > pos: 0 > flags: 02 > mnt_id: 9 > + inode_no: 63107 > clockid: 0 > ticks: 0 > settime flags: 01 > @@ -2031,6 +2040,22 @@ details]. 'it_value' is remaining time until the timer > expiration. > with TIMER_ABSTIME option which will be shown in 'settime flags', but > 'it_value' > still exhibits timer's remaining time. > > +DMA Buffer files > +~~~~~~~~~~~~~~~~ > + > +:: > + > + pos: 0 > + flags: 04002 > + mnt_id: 9 > + inode_no: 63107
Hi, Why do all of the examples have so many spaces between inode_no: and the number? Ah, it's a \t in the output along with the length of the "inode_no:" string. OK. Next question: why are there spaces instead of a tab between "inode_no": and the number? All of the other fields that are preceded by a \t in the seq_printf() call have tabs in the output. Except for the tabs vs. spaces, the Documentation change is: Acked-by: Randy Dunlap <[email protected]> > + size: 32768 > + count: 2 > + exp_name: system-heap > + > +where 'size' is the size of the DMA buffer in bytes. 'count' is the file > count of > +the DMA buffer file. 'exp_name' is the name of the DMA buffer exporter. > + > 3.9 /proc/<pid>/map_files - Information about memory mapped files > --------------------------------------------------------------------- > This directory contains symbolic links which represent memory mapped files > diff --git a/fs/proc/fd.c b/fs/proc/fd.c > index 585e213301f9..2c25909bf9d1 100644 > --- a/fs/proc/fd.c > +++ b/fs/proc/fd.c > @@ -54,9 +54,10 @@ static int seq_show(struct seq_file *m, void *v) > if (ret) > return ret; > > - seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\n", > + seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\ninode_no:\t%lu\n", > (long long)file->f_pos, f_flags, > - real_mount(file->f_path.mnt)->mnt_id); > + real_mount(file->f_path.mnt)->mnt_id, > + file_inode(file)->i_ino); > > /* show_fd_locks() never deferences files so a stale value is safe */ > show_fd_locks(m, file, files); > thanks. -- ~Randy
