Re: [Crash-utility] [PATCH] Fix "ps/vm" commands to display correct memory usage

Kernel commit eca56ff906bd ("mm, shmem: add internal shmem resident memory accounting"), which adds internal shmem resident memory accounting, and tallies into the mm_rss_stat counter. As a result, the "ps/vm" commands fail to show correct memory usage when a process uses an anonymous shared memory region. Without the patch: crash> ps 2150 PID PPID CPU TASK ST %MEM VSZ RSS COMM 2150 2105 14 ffff8fba86d74d40 IN 0.0 10488392 444 mmap_test ^^^

Currently, the "ps/vm" commands missed the shmem pages count, let's count the shmem pages together with regular files and anonymous pages. With the patch: crash> ps 2150 PID PPID CPU TASK ST %MEM VSZ RSS COMM 2150 2105 14 ffff8fba86d74d40 IN 20.8 10488392 3659008 mmap_test Reported-by: Buland Kumar Singh <bsingh(a)redhat.com&gt; Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com&gt; --- defs.h | 1 + memory.c | 59 ++++++++++++++++++++++++++++++++++++++++++-------------- task.c | 1 + 3 files changed, 46 insertions(+), 15 deletions(-) diff --git a/defs.h b/defs.h index 5ee60f1eb3a5..f784d40c0b17 100644 --- a/defs.h +++ b/defs.h @@ -887,6 +887,7 @@ struct task_table { /* kernel/local task table data */ int callbacks; struct task_context **context_by_task; /* task_context sorted by task addr */ ulong pid_xarray; + long shmempages; }; #define TASK_INIT_DONE (0x1) diff --git a/memory.c b/memory.c index acbee6389472..df85b69963b6 100644 --- a/memory.c +++ b/memory.c @@ -4466,13 +4466,13 @@ in_user_stack(ulong task, ulong vaddr) } /* - * Set the const value of filepages and anonpages - * according to MM_FILEPAGES and MM_ANONPAGES. + * Set the const value of filepages, anonpages and shmempages + * according to MM_FILEPAGES, MM_ANONPAGES and MM_SHMEMPAGES. */ static void rss_page_types_init(void) { - long anonpages, filepages; + long anonpages, filepages, shmempages; if (VALID_MEMBER(mm_struct_rss)) return; @@ -4487,6 +4487,15 @@ rss_page_types_init(void) } tt->filepages = filepages; tt->anonpages = anonpages; + + /* + * The default value(MM_SHMEMPAGES) is 3, which is introduced + * in linux v4.5-rc1 and later. See commit eca56ff906bd. + */ + if (!enumerator_value("MM_SHMEMPAGES", &shmempages)) + tt->shmempages = -1; + else + tt->shmempages = shmempages; } } @@ -4812,10 +4821,11 @@ get_task_mem_usage(ulong task, struct task_mem_usage *tm) * Latest kernels have mm_struct.mm_rss_stat[]. */ if (VALID_MEMBER(mm_struct_rss_stat) && VALID_MEMBER(mm_rss_stat_count)) { - long anonpages, filepages, count; + long anonpages, filepages, shmempages, count; anonpages = tt->anonpages; filepages = tt->filepages; + shmempages = tt->shmempages; count = LONG(tt->mm_struct + OFFSET(mm_struct_rss_stat) + OFFSET(mm_rss_stat_count) + @@ -4836,6 +4846,15 @@ get_task_mem_usage(ulong task, struct task_mem_usage *tm) if (count > 0) rss += count; + if (shmempages > 0) {