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| author | Alexey Dobriyan <adobriyan@gmail.com> | 2020-04-07 06:09:05 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-04-07 20:43:42 +0300 |
| commit | 5c5ab9714c2225d50119e397c537ad5e568f268b (patch) | |
| tree | 9a68b7a199b7b287098b3197850fbff446bdcfb5 /fs/proc/array.c | |
| parent | d919b33dafb3e222d23671b2bb06d119aede625f (diff) | |
| download | linux-5c5ab9714c2225d50119e397c537ad5e568f268b.tar.xz | |
proc: speed up /proc/*/statm
top(1) reads all /proc/*/statm files but kernel threads will always have
zeros. Print those zeroes directly without going through
seq_put_decimal_ull().
Speed up reading /proc/2/statm (which is kthreadd) is like 3%.
My system has more kernel threads than normal processes after booting KDE.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200307154435.GA2788@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc/array.c')
| -rw-r--r-- | fs/proc/array.c | 39 |
1 files changed, 23 insertions, 16 deletions
diff --git a/fs/proc/array.c b/fs/proc/array.c index 5efaf3708ec6..8e16f14bb05a 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -635,28 +635,35 @@ int proc_tgid_stat(struct seq_file *m, struct pid_namespace *ns, int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *task) { - unsigned long size = 0, resident = 0, shared = 0, text = 0, data = 0; struct mm_struct *mm = get_task_mm(task); if (mm) { + unsigned long size; + unsigned long resident = 0; + unsigned long shared = 0; + unsigned long text = 0; + unsigned long data = 0; + size = task_statm(mm, &shared, &text, &data, &resident); mmput(mm); - } - /* - * For quick read, open code by putting numbers directly - * expected format is - * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n", - * size, resident, shared, text, data); - */ - seq_put_decimal_ull(m, "", size); - seq_put_decimal_ull(m, " ", resident); - seq_put_decimal_ull(m, " ", shared); - seq_put_decimal_ull(m, " ", text); - seq_put_decimal_ull(m, " ", 0); - seq_put_decimal_ull(m, " ", data); - seq_put_decimal_ull(m, " ", 0); - seq_putc(m, '\n'); + /* + * For quick read, open code by putting numbers directly + * expected format is + * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n", + * size, resident, shared, text, data); + */ + seq_put_decimal_ull(m, "", size); + seq_put_decimal_ull(m, " ", resident); + seq_put_decimal_ull(m, " ", shared); + seq_put_decimal_ull(m, " ", text); + seq_put_decimal_ull(m, " ", 0); + seq_put_decimal_ull(m, " ", data); + seq_put_decimal_ull(m, " ", 0); + seq_putc(m, '\n'); + } else { + seq_write(m, "0 0 0 0 0 0 0\n", 14); + } return 0; } |