From: Yixuan Cao caoyixuan2019@email.szu.edu.cn
mainline inclusion from mainline-v5.18-rc1 commit bf215eab785a30756ea1e53b62a5638d1177a795 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I9GSSR
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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In a single-threaded process, the pid in kernel task_struct is the same as the tgid, which can mark the process of page allocation. But in a multithreaded process, only the task_struct of the thread leader has the same pid as tgid, and the pids of other threads are different from tgid. Therefore, tgid is recorded to provide effective information for debugging and data statistics of multithreaded programs.
This can also be achieved by observing the task name (executable file name) for a specific process. However, when the same program is started multiple times, the task name is the same and the tgid is different. Therefore, in the debugging of multi-threaded programs, combined with the task name and tgid, more accurate runtime information of a certain run of the program can be obtained.
Link: https://lkml.kernel.org/r/20220219180450.2399-1-caoyixuan2019@email.szu.edu.... Signed-off-by: Yixuan Cao caoyixuan2019@email.szu.edu.cn Cc: Waiman Long longman@redhat.com Cc: Rafael Aquini aquini@redhat.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org
Conflicts: mm/page_owner.c [context conflicts] Signed-off-by: Jinjiang Tu tujinjiang@huawei.com --- mm/page_owner.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/mm/page_owner.c b/mm/page_owner.c index 0b4b5b204257..ce44df1d603a 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -31,6 +31,7 @@ struct page_owner { u64 free_ts_nsec; char comm[TASK_COMM_LEN]; pid_t pid; + pid_t tgid; };
static bool page_owner_enabled = false; @@ -172,6 +173,7 @@ static inline void __set_page_owner_handle(struct page *page, page_owner->gfp_mask = gfp_mask; page_owner->last_migrate_reason = -1; page_owner->pid = current->pid; + page_owner->tgid = current->tgid; page_owner->ts_nsec = local_clock(); strlcpy(page_owner->comm, current->comm, sizeof(page_owner->comm)); @@ -240,6 +242,7 @@ void __copy_page_owner(struct page *oldpage, struct page *newpage) old_page_owner->last_migrate_reason; new_page_owner->handle = old_page_owner->handle; new_page_owner->pid = old_page_owner->pid; + new_page_owner->tgid = old_page_owner->tgid; new_page_owner->ts_nsec = old_page_owner->ts_nsec; new_page_owner->free_ts_nsec = old_page_owner->ts_nsec; strcpy(new_page_owner->comm, old_page_owner->comm); @@ -395,11 +398,11 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, return -ENOMEM;
ret = scnprintf(kbuf, count, - "Page allocated via order %u, mask %#x(%pGg), pid %d (%s), ts %llu ns, free_ts %llu ns\n", + "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu ns, free_ts %llu ns\n", page_owner->order, page_owner->gfp_mask, &page_owner->gfp_mask, page_owner->pid, - page_owner->comm, page_owner->ts_nsec, - page_owner->free_ts_nsec); + page_owner->tgid, page_owner->comm, + page_owner->ts_nsec, page_owner->free_ts_nsec);
/* Print information relevant to grouping pages by mobility */ pageblock_mt = get_pageblock_migratetype(page); @@ -469,10 +472,10 @@ void __dump_page_owner(struct page *page) else pr_alert("page_owner tracks the page as freed\n");
- pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(%pGg), pid %d (%s), ts %llu, free_ts %llu\n", + pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu, free_ts %llu\n", page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask, - page_owner->pid, page_owner->comm, page_owner->ts_nsec, - page_owner->free_ts_nsec); + page_owner->pid, page_owner->tgid, page_owner->comm, + page_owner->ts_nsec, page_owner->free_ts_nsec);
handle = READ_ONCE(page_owner->handle); if (!handle) {