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Date: Tue, 3 Jul 2018 09:36:45 +0200
From: Vlastimil Babka <vbabka@...e.cz>
To: Thomas Lindroth <thomas.lindroth@...il.com>, dancol@...gle.com,
Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-api@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-mm <linux-mm@...ck.org>
Subject: Re: [REGRESSION] "Locked" and "Pss" in /proc/*/smaps are the same
+CC
On 07/01/2018 08:31 PM, Thomas Lindroth wrote:
> While looking around in /proc on my v4.14.52 system I noticed that
> all processes got a lot of "Locked" memory in /proc/*/smaps. A lot
> more memory than a regular user can usually lock with mlock().
>
> commit 493b0e9d945fa9dfe96be93ae41b4ca4b6fdb317 (v4.14-rc1) seems
> to have changed the behavior of "Locked".
>
> commit 493b0e9d945fa9dfe96be93ae41b4ca4b6fdb317
> Author: Daniel Colascione <dancol@...gle.com>
> Date: Wed Sep 6 16:25:08 2017 -0700
>
> mm: add /proc/pid/smaps_rollup
>
> Before that commit the code was like this. Notice the VM_LOCKED
> check.
>
> seq_printf(m,
> "Size: %8lu kB\n"
> "Rss: %8lu kB\n"
> "Pss: %8lu kB\n"
> "Shared_Clean: %8lu kB\n"
> "Shared_Dirty: %8lu kB\n"
> "Private_Clean: %8lu kB\n"
> "Private_Dirty: %8lu kB\n"
> "Referenced: %8lu kB\n"
> "Anonymous: %8lu kB\n"
> "LazyFree: %8lu kB\n"
> "AnonHugePages: %8lu kB\n"
> "ShmemPmdMapped: %8lu kB\n"
> "Shared_Hugetlb: %8lu kB\n"
> "Private_Hugetlb: %7lu kB\n"
> "Swap: %8lu kB\n"
> "SwapPss: %8lu kB\n"
> "KernelPageSize: %8lu kB\n"
> "MMUPageSize: %8lu kB\n"
> "Locked: %8lu kB\n",
> (vma->vm_end - vma->vm_start) >> 10,
> mss.resident >> 10,
> (unsigned long)(mss.pss >> (10 + PSS_SHIFT)),
> mss.shared_clean >> 10,
> mss.shared_dirty >> 10,
> mss.private_clean >> 10,
> mss.private_dirty >> 10,
> mss.referenced >> 10,
> mss.anonymous >> 10,
> mss.lazyfree >> 10,
> mss.anonymous_thp >> 10,
> mss.shmem_thp >> 10,
> mss.shared_hugetlb >> 10,
> mss.private_hugetlb >> 10,
> mss.swap >> 10,
> (unsigned long)(mss.swap_pss >> (10 + PSS_SHIFT)),
> vma_kernel_pagesize(vma) >> 10,
> vma_mmu_pagesize(vma) >> 10,
> (vma->vm_flags & VM_LOCKED) ?
> (unsigned long)(mss.pss >> (10 + PSS_SHIFT)) : 0);
>
> After that commit Locked is now the same as Pss. This looks like a
> mistake.
>
> seq_printf(m,
> "Rss: %8lu kB\n"
> "Pss: %8lu kB\n"
> "Shared_Clean: %8lu kB\n"
> "Shared_Dirty: %8lu kB\n"
> "Private_Clean: %8lu kB\n"
> "Private_Dirty: %8lu kB\n"
> "Referenced: %8lu kB\n"
> "Anonymous: %8lu kB\n"
> "LazyFree: %8lu kB\n"
> "AnonHugePages: %8lu kB\n"
> "ShmemPmdMapped: %8lu kB\n"
> "Shared_Hugetlb: %8lu kB\n"
> "Private_Hugetlb: %7lu kB\n"
> "Swap: %8lu kB\n"
> "SwapPss: %8lu kB\n"
> "Locked: %8lu kB\n",
> mss->resident >> 10,
> (unsigned long)(mss->pss >> (10 + PSS_SHIFT)),
> mss->shared_clean >> 10,
> mss->shared_dirty >> 10,
> mss->private_clean >> 10,
> mss->private_dirty >> 10,
> mss->referenced >> 10,
> mss->anonymous >> 10,
> mss->lazyfree >> 10,
> mss->anonymous_thp >> 10,
> mss->shmem_thp >> 10,
> mss->shared_hugetlb >> 10,
> mss->private_hugetlb >> 10,
> mss->swap >> 10,
> (unsigned long)(mss->swap_pss >> (10 + PSS_SHIFT)),
> (unsigned long)(mss->pss >> (10 + PSS_SHIFT)));
>
> The latest git has changed a bit but the functionality is the
> same.
----8<----
>From fa721521c981167c24ac8f4be446443d293d741e Mon Sep 17 00:00:00 2001
From: Vlastimil Babka <vbabka@...e.cz>
Date: Tue, 3 Jul 2018 09:24:27 +0200
Subject: [PATCH] mm: fix Locked field in /proc/pid/smaps*
Thomas reports:
: While looking around in /proc on my v4.14.52 system I noticed that
: all processes got a lot of "Locked" memory in /proc/*/smaps. A lot
: more memory than a regular user can usually lock with mlock().
:
: commit 493b0e9d945fa9dfe96be93ae41b4ca4b6fdb317 (v4.14-rc1) seems
: to have changed the behavior of "Locked".
:
: Before that commit the code was like this. Notice the VM_LOCKED
: check.
:
: (vma->vm_flags & VM_LOCKED) ?
: (unsigned long)(mss.pss >> (10 + PSS_SHIFT)) : 0);
:
: After that commit Locked is now the same as Pss. This looks like a
: mistake.
:
: (unsigned long)(mss->pss >> (10 + PSS_SHIFT)));
Indeed, the commit has added mss->pss_locked with the correct value that
depends on VM_LOCKED, but forgot to actually use it. Fix it.
Fixes: 493b0e9d945f ("mm: add /proc/pid/smaps_rollup")
Reported-by: Thomas Lindroth <thomas.lindroth@...il.com>
Signed-off-by: Vlastimil Babka <vbabka@...e.cz>
Cc: stable@...r.kernel.org
---
fs/proc/task_mmu.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index e9679016271f..dfd73a4616ce 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -831,7 +831,8 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
SEQ_PUT_DEC(" kB\nSwap: ", mss->swap);
SEQ_PUT_DEC(" kB\nSwapPss: ",
mss->swap_pss >> PSS_SHIFT);
- SEQ_PUT_DEC(" kB\nLocked: ", mss->pss >> PSS_SHIFT);
+ SEQ_PUT_DEC(" kB\nLocked: ",
+ mss->pss_locked >> PSS_SHIFT);
seq_puts(m, " kB\n");
}
if (!rollup_mode) {
--
2.18.0
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