From: Michal Hocko <mhocko@suse.com>
To: liuhailong@oppo.com
Cc: akpm@linux-foundation.org, nathan@kernel.org,
ndesaulniers@google.com, trix@redhat.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
surenb@google.com, zhaoyang.huang@unisoc.com,
quic_charante@quicinc.com, yuzhao@google.com
Subject: Re: [PATCH v2] Revert "mm: skip CMA pages when they are not available"
Date: Tue, 19 Mar 2024 09:55:37 +0100 [thread overview]
Message-ID: <ZflTCY-Oaxm0U70u@tiehlicka> (raw)
In-Reply-To: <20240315081803.2223-1-liuhailong@oppo.com>
On Fri 15-03-24 16:18:03, liuhailong@oppo.com wrote:
> From: "Hailong.Liu" <liuhailong@oppo.com>
>
> This reverts
> commit b7108d66318a ("Multi-gen LRU: skip CMA pages when they are not eligible")
> commit 5da226dbfce3 ("mm: skip CMA pages when they are not available")
>
> skip_cma may cause system not responding. if cma pages is large in lru_list
> and system is in lowmemory, many tasks would direct reclaim and waste
> cpu time to isolate_lru_pages and return.
>
> Test this patch on android-5.15 8G device
> reproducer:
> - cma_declare_contiguous 3G pages
> - set /proc/sys/vm/swappiness 0 to enable direct_reclaim reclaim file
> only.
> - run a memleak process in userspace
Does this represent a sane configuration? CMA memory is unusable for
kernel allocations and memleak process is also hard to reclaim due to
swap suppression. Isn't such a system doomed to struggle to reclaim any
memory? Btw. how does the same setup behave with the regular LRU
implementation? My guess would be that it would struggle as well.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2024-03-19 8:55 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-14 14:15 [PATCH] Revert "mm: skip CMA pages when they are not available" liuhailong
2024-03-14 17:47 ` Yu Zhao
2024-03-15 7:41 ` reply: " 黄朝阳 (Zhaoyang Huang)
2024-03-15 10:36 ` 刘海龙(LaoLiu)
2024-03-15 8:18 ` [PATCH v2] " liuhailong
2024-03-15 8:46 ` Barry Song
2024-03-15 10:43 ` 刘海龙(LaoLiu)
2024-03-17 5:47 ` Barry Song
2024-03-19 8:55 ` Michal Hocko [this message]
2024-03-19 11:09 ` Barry Song
2024-03-19 12:27 ` 刘海龙(LaoLiu)
2024-03-22 1:25 ` Barry Song
2024-03-19 13:40 ` Michal Hocko
2024-03-22 1:28 ` Barry Song
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