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Date:   Fri, 9 Jun 2023 15:35:19 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     "zhaoyang.huang" <zhaoyang.huang@unisoc.com>
Cc:     Matthew Wilcox <willy@infradead.org>,
        Suren Baghdasaryan <surenb@google.com>,
        Minchan Kim <minchan@kernel.org>, <linux-mm@kvack.org>,
        <linux-kernel@vger.kernel.org>,
        Zhaoyang Huang <huangzhaoyang@gmail.com>, <ke.wang@unisoc.com>
Subject: Re: [PATCHv5] mm: skip CMA pages when they are not available
Message-Id: <20230609153519.ff01046ef0faff00a74bd5b0@linux-foundation.org>
In-Reply-To: <1685501461-19290-1-git-send-email-zhaoyang.huang@unisoc.com>
References: <1685501461-19290-1-git-send-email-zhaoyang.huang@unisoc.com>
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On Wed, 31 May 2023 10:51:01 +0800 "zhaoyang.huang" <zhaoyang.huang@unisoc.com> wrote:

> From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
> 
> This patch fixes unproductive reclaiming of CMA pages by skipping them when they
> are not available for current context. It is arise from bellowing OOM issue, which
> caused by large proportion of MIGRATE_CMA pages among free pages.
> 
> [   36.172486] [03-19 10:05:52.172] ActivityManager: page allocation failure: order:0, mode:0xc00(GFP_NOIO), nodemask=(null),cpuset=foreground,mems_allowed=0
> [   36.189447] [03-19 10:05:52.189] DMA32: 0*4kB 447*8kB (C) 217*16kB (C) 124*32kB (C) 136*64kB (C) 70*128kB (C) 22*256kB (C) 3*512kB (C) 0*1024kB 0*2048kB 0*4096kB = 35848kB
> [   36.193125] [03-19 10:05:52.193] Normal: 231*4kB (UMEH) 49*8kB (MEH) 14*16kB (H) 13*32kB (H) 8*64kB (H) 2*128kB (H) 0*256kB 1*512kB (H) 0*1024kB 0*2048kB 0*4096kB = 3236kB
> ...
> [   36.234447] [03-19 10:05:52.234] SLUB: Unable to allocate memory on node -1, gfp=0xa20(GFP_ATOMIC)
> [   36.234455] [03-19 10:05:52.234] cache: ext4_io_end, object size: 64, buffer size: 64, default order: 0, min order: 0
> [   36.234459] [03-19 10:05:52.234] node 0: slabs: 53,objs: 3392, free: 0
> 

We saw plenty of feedback for earlier versions, but now silence.  Does
this mean we're all OK with v5?