On Tue, Jun 28, 2022 at 4:54 AM Brian Foster <bfoster@xxxxxxxxxx> wrote: > > On Thu, Jun 23, 2022 at 03:06:06PM -0700, Kalesh Singh wrote: > > To be able to account the amount of memory a process is keeping pinned > > by open file descriptors add a 'size' field to fdinfo output. > > > > dmabufs fds already expose a 'size' field for this reason, remove this > > and make it a common field for all fds. This allows tracking of > > other types of memory (e.g. memfd and ashmem in Android). > > > > Signed-off-by: Kalesh Singh <kaleshsingh@xxxxxxxxxx> > > Reviewed-by: Christian König <christian.koenig@xxxxxxx> > > --- > > > > Changes in v2: > > - Add Christian's Reviewed-by > > > > Changes from rfc: > > - Split adding 'size' and 'path' into a separate patches, per Christian > > - Split fdinfo seq_printf into separate lines, per Christian > > - Fix indentation (use tabs) in documentaion, per Randy > > > > Documentation/filesystems/proc.rst | 12 ++++++++++-- > > drivers/dma-buf/dma-buf.c | 1 - > > fs/proc/fd.c | 9 +++++---- > > 3 files changed, 15 insertions(+), 7 deletions(-) > > > ... > > diff --git a/fs/proc/fd.c b/fs/proc/fd.c > > index 913bef0d2a36..464bc3f55759 100644 > > --- a/fs/proc/fd.c > > +++ b/fs/proc/fd.c > > @@ -54,10 +54,11 @@ 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\nino:\t%lu\n", > > - (long long)file->f_pos, f_flags, > > - real_mount(file->f_path.mnt)->mnt_id, > > - file_inode(file)->i_ino); > > + seq_printf(m, "pos:\t%lli\n", (long long)file->f_pos); > > + seq_printf(m, "flags:\t0%o\n", f_flags); > > + seq_printf(m, "mnt_id:\t%i\n", real_mount(file->f_path.mnt)->mnt_id); > > + seq_printf(m, "ino:\t%lu\n", file_inode(file)->i_ino); > > + seq_printf(m, "size:\t%lli\n", (long long)file_inode(file)->i_size); > > Hi Kalesh, > > Any reason not to use i_size_read() here? Hi Brian. Thanks for pointing this out. You are right, we should use i_size_read() here. I'll update in the next version. > > Also not sure if it matters that much for your use case, but something > worth noting at least with shmem is that one can do something like: > > # cat /proc/meminfo | grep Shmem: > Shmem: 764 kB > # xfs_io -fc "falloc -k 0 10m" ./file > # ls -alh file > -rw-------. 1 root root 0 Jun 28 07:22 file > # stat file > File: file > Size: 0 Blocks: 20480 IO Block: 4096 regular empty file > # cat /proc/meminfo | grep Shmem: > Shmem: 11004 kB > > ... where the resulting memory usage isn't reflected in i_size (but is > is in i_blocks/bytes). I tried a similar experiment a few times, but I don't see the same results. In my case, there is not any change in shmem. IIUC the fallocate is allocating the disk space not shared memory. cat /proc/meminfo > meminfo.start xfs_io -fc "falloc -k 0 50m" ./xfs_file cat /proc/meminfo > meminfo.stop tail -n +1 meminfo.st* | grep -i '==\|Shmem:' ==> meminfo.start <== Shmem: 484 kB ==> meminfo.stop <== Shmem: 484 kB ls -lh xfs_file -rw------- 1 root root 0 Jun 28 15:12 xfs_file stat xfs_file File: xfs_file Size: 0 Blocks: 102400 IO Block: 4096 regular empty file Thanks, Kalesh > > Brian > > > > > /* show_fd_locks() never deferences files so a stale value is safe */ > > show_fd_locks(m, file, files); > > -- > > 2.37.0.rc0.161.g10f37bed90-goog > > >
