From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Yang Yingliang <yangyingliang@huawei.com>,
akpm@linux-foundation.org, ljs@kernel.org,
Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org,
surenb@google.com, mhocko@suse.com
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
hucool.lihua@huawei.com
Subject: Re: [PATCH -next] mm: make sure freeram is smaller than totalram
Date: Mon, 20 Apr 2026 21:03:04 +0200 [thread overview]
Message-ID: <5bebc75d-19e7-4d06-a5c1-d3f0bb5f4e05@kernel.org> (raw)
In-Reply-To: <20260413115736.1237680-1-yangyingliang@huawei.com>
On 4/13/26 13:57, Yang Yingliang wrote:
> The memory stat is not done in real time, it have some gap with
> real value. In CPU-less NUMA node, the values of MemTotal and
> MemFree can be nearly equal, the gap may cause MemFree bigger
> than MemTotal, it leads MemUsed is negative which print as a large
> positive number.
How does this interact with CPU-less NUMA node? Some concurrent memory
hotunplug, or how could be possible get MemFree that is larger than
MemTotal?
>
> cat /sys/devices/system/node/node17/meminfo
> Node 17 MemTotal: 4194304 kB
> Node 17 MemFree: 4195552 kB
> Node 17 MemUsed: 18446744073709550368 kB
> Node 17 Active: 52 kB
> Node 17 Inactive: 320 kB
> Node 17 Active(anon): 0 kB
> Node 17 Inactive(anon): 0 kB
> Node 17 Active(file): 52 kB
> Node 17 Inactive(file): 320 kB
> Node 17 Unevictable: 0 kB
> Node 17 Mlocked: 0 kB
> Node 17 Dirty: 0 kB
> Node 17 Writeback: 0 kB
> Node 17 FilePages: 372 kB
> Node 17 Mapped: 320 kB
> Node 17 AnonPages: 0 kB
> Node 17 Shmem: 0 kB
> Node 17 KernelStack: 0 kB
> Node 17 PageTables: 0 kB
> Node 17 NFS_Unstable: 0 kB
> Node 17 Bounce: 0 kB
> Node 17 WritebackTmp: 0 kB
> Node 17 KReclaimable: 0 kB
> Node 17 Slab: 0 kB
> Node 17 SReclaimable: 0 kB
> Node 17 SUnreclaim: 0 kB
> Node 17 AnonHugePages: 79872 kB
> Node 17 ShmemHugePages: 0 kB
> Node 17 ShmemPmdMapped: 0 kB
> Node 17 FileHugePages: 0 kB
> Node 17 FilePmdMapped: 0 kB
> Node 17 HugePages_Total: 0
> Node 17 HugePages_Free: 0
> Node 17 HugePages_Surp: 0
>
> To avoid this exception by refreshing vm_stat, when MemFree
> is bigger than MemTotal.
>
--
Cheers,
David
prev parent reply other threads:[~2026-04-20 19:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-13 11:57 [PATCH -next] mm: make sure freeram is smaller than totalram Yang Yingliang
2026-04-15 11:20 ` kernel test robot
2026-04-20 19:03 ` David Hildenbrand (Arm) [this message]
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