From: Yang Shi <yang.shi@linux.alibaba.com>
To: rientjes@google.com, kirill.shutemov@linux.intel.com,
mhocko@suse.com, hannes@cmpxchg.org, akpm@linux-foundation.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2 -mm] mm: account lazy free pages into available memory
Date: Mon, 8 Jul 2019 15:53:05 -0700 [thread overview]
Message-ID: <18a6c461-5300-34ec-3a0f-266c72a2733b@linux.alibaba.com> (raw)
In-Reply-To: <1561655524-89276-2-git-send-email-yang.shi@linux.alibaba.com>
And how about this one?
On 6/27/19 10:12 AM, Yang Shi wrote:
> Available memory is one of the most important metrics for memory
> pressure. Currently, lazy free pages are not accounted into available
> memory, but they are reclaimable actually, like reclaimable slabs.
>
> Accounting lazy free pages into available memory should reflect the real
> memory pressure status, and also would help administrators and/or other
> high level scheduling tools make better decision.
>
> The /proc/meminfo would show more available memory with test which
> creates ~1GB deferred split THP.
>
> Before:
> MemAvailable: 43544272 kB
> ...
> AnonHugePages: 10240 kB
> ShmemHugePages: 0 kB
> ShmemPmdMapped: 0 kB
> LazyFreePages: 1046528 kB
>
> After:
> MemAvailable: 44415124 kB
> ...
> AnonHugePages: 6144 kB
> ShmemHugePages: 0 kB
> ShmemPmdMapped: 0 kB
> LazyFreePages: 1046528 kB
>
> MADV_FREE pages are not accounted for NR_LAZYFREE since they have been
> put on inactive file LRU and accounted into available memory.
> Accounting here would double account them.
>
> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
> ---
> mm/page_alloc.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index cab50e8..58ceca5 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5005,6 +5005,7 @@ long si_mem_available(void)
> unsigned long wmark_low = 0;
> unsigned long pages[NR_LRU_LISTS];
> unsigned long reclaimable;
> + unsigned long lazyfree;
> struct zone *zone;
> int lru;
>
> @@ -5038,6 +5039,10 @@ long si_mem_available(void)
> global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE);
> available += reclaimable - min(reclaimable / 2, wmark_low);
>
> + /* Lazyfree pages are reclaimable when memory pressure is hit */
> + lazyfree = global_node_page_state(NR_LAZYFREE);
> + available += lazyfree - min(lazyfree / 2, wmark_low);
> +
> if (available < 0)
> available = 0;
> return available;
next prev parent reply other threads:[~2019-07-08 22:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-27 17:12 [PATCH 1/2 -mm] mm: account lazy free pages separately Yang Shi
2019-06-27 17:12 ` [PATCH 2/2 -mm] mm: account lazy free pages into available memory Yang Shi
2019-07-08 22:53 ` Yang Shi [this message]
2019-07-08 22:52 ` [PATCH 1/2 -mm] mm: account lazy free pages separately Yang Shi
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