From: "tip-bot2 for Song Liu" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Hechao Li <hechaol@fb.com>, Song Liu <songliubraving@fb.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
<kernel-team@fb.com>, Jie Meng <jmeng@fb.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
linux-kernel@vger.kernel.org
Subject: [tip: perf/urgent] perf/core: Rework memory accounting in perf_mmap()
Date: Wed, 09 Oct 2019 12:59:19 -0000 [thread overview]
Message-ID: <157062595964.9978.13325399994782902718.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20190904214618.3795672-1-songliubraving@fb.com>
The following commit has been merged into the perf/urgent branch of tip:
Commit-ID: d44248a41337731a111374822d7d4451b64e73e4
Gitweb: https://git.kernel.org/tip/d44248a41337731a111374822d7d4451b64e73e4
Author: Song Liu <songliubraving@fb.com>
AuthorDate: Wed, 04 Sep 2019 14:46:18 -07:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 09 Oct 2019 12:44:12 +02:00
perf/core: Rework memory accounting in perf_mmap()
perf_mmap() always increases user->locked_vm. As a result, "extra" could
grow bigger than "user_extra", which doesn't make sense. Here is an
example case:
(Note: Assume "user_lock_limit" is very small.)
| # of perf_mmap calls |vma->vm_mm->pinned_vm|user->locked_vm|
| 0 | 0 | 0 |
| 1 | user_extra | user_extra |
| 2 | 3 * user_extra | 2 * user_extra|
| 3 | 6 * user_extra | 3 * user_extra|
| 4 | 10 * user_extra | 4 * user_extra|
Fix this by maintaining proper user_extra and extra.
Reviewed-By: Hechao Li <hechaol@fb.com>
Reported-by: Hechao Li <hechaol@fb.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <kernel-team@fb.com>
Cc: Jie Meng <jmeng@fb.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190904214618.3795672-1-songliubraving@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/events/core.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index f953dd1..2b8265a 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5668,7 +5668,8 @@ again:
* undo the VM accounting.
*/
- atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
+ atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
+ &mmap_user->locked_vm);
atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
free_uid(mmap_user);
@@ -5812,8 +5813,20 @@ accounting:
user_locked = atomic_long_read(&user->locked_vm) + user_extra;
- if (user_locked > user_lock_limit)
+ if (user_locked <= user_lock_limit) {
+ /* charge all to locked_vm */
+ } else if (atomic_long_read(&user->locked_vm) >= user_lock_limit) {
+ /* charge all to pinned_vm */
+ extra = user_extra;
+ user_extra = 0;
+ } else {
+ /*
+ * charge locked_vm until it hits user_lock_limit;
+ * charge the rest from pinned_vm
+ */
extra = user_locked - user_lock_limit;
+ user_extra -= extra;
+ }
lock_limit = rlimit(RLIMIT_MEMLOCK);
lock_limit >>= PAGE_SHIFT;
prev parent reply other threads:[~2019-10-09 12:59 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-04 21:46 [PATCH] perf: rework memory accounting in perf_mmap() Song Liu
2019-09-16 19:43 ` Song Liu
2019-09-16 20:10 ` Hechao Li
2019-09-30 5:33 ` Song Liu
2019-09-30 9:02 ` Peter Zijlstra
2019-10-07 16:31 ` Song Liu
2019-10-07 16:56 ` Peter Zijlstra
2019-10-09 12:59 ` tip-bot2 for Song Liu [this message]
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