diff options
| author | Jin Qian <jinqian@google.com> | 2017-02-28 15:09:42 -0800 |
|---|---|---|
| committer | Mister Oyster <oysterized@gmail.com> | 2017-05-23 13:00:33 +0200 |
| commit | 61597b1634e85b2e7c6d4f83bddeb0692c14b87c (patch) | |
| tree | 9625a5004196dbc7b0710424036c1603f89ad68f /drivers/misc/uid_sys_stats.c | |
| parent | a571c7301b1ea6433176320185b670e1b26034d9 (diff) | |
ANDROID: uid_sys_stats: fix negative write bytes.
A task can cancel writes made by other tasks. In rare cases,
cancelled_write_bytes is larger than write_bytes if the task
itself didn't make any write. This doesn't affect total size
but may cause confusion when looking at IO usage on individual
tasks.
Bug: 35851986
Change-Id: If6cb549aeef9e248e18d804293401bb2b91918ca
Signed-off-by: Jin Qian <jinqian@google.com>
Diffstat (limited to 'drivers/misc/uid_sys_stats.c')
| -rw-r--r-- | drivers/misc/uid_sys_stats.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/drivers/misc/uid_sys_stats.c b/drivers/misc/uid_sys_stats.c index 5d7d16dfd..356826946 100644 --- a/drivers/misc/uid_sys_stats.c +++ b/drivers/misc/uid_sys_stats.c @@ -233,14 +233,21 @@ static const struct file_operations uid_remove_fops = { .write = uid_remove_write, }; +static u64 compute_write_bytes(struct task_struct *task) +{ + if (task->ioac.write_bytes <= task->ioac.cancelled_write_bytes) + return 0; + + return task->ioac.write_bytes - task->ioac.cancelled_write_bytes; +} + static void add_uid_io_curr_stats(struct uid_entry *uid_entry, struct task_struct *task) { struct io_stats *io_curr = &uid_entry->io[UID_STATE_TOTAL_CURR]; io_curr->read_bytes += task->ioac.read_bytes; - io_curr->write_bytes += - task->ioac.write_bytes - task->ioac.cancelled_write_bytes; + io_curr->write_bytes += compute_write_bytes(task); io_curr->rchar += task->ioac.rchar; io_curr->wchar += task->ioac.wchar; } @@ -251,8 +258,7 @@ static void clean_uid_io_last_stats(struct uid_entry *uid_entry, struct io_stats *io_last = &uid_entry->io[UID_STATE_TOTAL_LAST]; io_last->read_bytes -= task->ioac.read_bytes; - io_last->write_bytes -= - task->ioac.write_bytes - task->ioac.cancelled_write_bytes; + io_last->write_bytes -= compute_write_bytes(task); io_last->rchar -= task->ioac.rchar; io_last->wchar -= task->ioac.wchar; } |