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t=1777016466; bh=3rB/wWr7rqw/j1uEBolZQokNV4lOe0WlNZrmBF3V1u8=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=YV3Tm15xoAmLGQ5bSLY4D5TJxsgXWooz/RG1cwy8Mu542xdrgJGNcZhHvlGnRPwZe MRI3aIQmUCwNiBcr4eDYjtW4I3/GSZi0GXFonATgTBgpVbu93jkMybCexcLCk7cQzJ kaSHLcvscf860Nvfg026aw29iz/1NL2KmlsB5UFp5nf+mzZ+sP0YBHHH+ZFjB5NIBI DlW5CC3pBJYXWDyGFjB/RAx3rS3PQFtDXUBjn/GuN3caJE3PPYshhmuVDoJh4OAatC y6FYrt8dNO/2mU3HYblY8k6nXTDWiJ/jhvaL1dqf0bDeb1oqT71JcuwWkyoDdVhe4O SaEt+0UY2z6nA== Message-ID: Date: Fri, 24 Apr 2026 09:41:01 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC 0/3] mm: process_mrelease: expedited reclaim and auto-kill support To: Suren Baghdasaryan Cc: Michal Hocko , Minchan Kim , akpm@linux-foundation.org, brauner@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, timmurray@google.com, Johannes Weiner References: <20260413223948.556351-1-minchan@kernel.org> <28c3ae9f-c974-454c-b8ed-ba0ba0a5706d@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: F29DDC0012 X-Stat-Signature: ngw1iqiy4zk7q73usghcufz9ywzfsmem X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1777016466-70143 X-HE-Meta: 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 /XJOyBum Mcm0neCRyAU5glpnqiwimjvWP12z29D/Gt7sV0qctamEMMqhVMV5vcdRJ3Zoyx3nbhdf5KHLVIFnhrzNDUTEO46oNiNeo5rmy++k+6OUGW8Tq+DZTQkbRqAB20LV4VsdnTps0aPNWHuXiSGxx1VkRwQsl+9aCc7gnalJZ4+duYEhF1f5oOotQbFboS1IfnsVF1FqO0KxqqH4RyA6oPPF1y55N9kDCDuxY09kkFwJ0LYVQkqpb5V+u1AN0AhaBZlqPXWajIXMSI1zy4A7jplVGTEcOD9DN03fRMfq3YIKouVArrf8i7Dl9eHBrQca9Vhx8F4CkVIoyX2BreLVe3/o2B+WQidjDdFAmG+t0 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/24/26 00:36, Suren Baghdasaryan wrote: > On Thu, Apr 23, 2026 at 2:50 AM David Hildenbrand (Arm) > wrote: >> >> On 4/23/26 09:50, Michal Hocko wrote: >>> [...] >>> >>> This is a very creative/disruptive way to do a memory reclaim. From a >>> user POV I would much rather see clean page cache reclaimed before my >>> apps start to disappear. But this is obviously your call and your users >>> that will care. >>> >>> Anyway, I still maintain my position. I do not think it is a good >>> idea to drop clean page cache as you do not know whether there are other >>> users. > > I'm very much familiar with these issues in Android and really want to > find a good solution for them. IIUC, this RFC tries to address 2 > things at once: > 1. handling clean private page cache when reaping memory of a kill victim; > 2. addressing a race between kill() and process_release() when > process_release() can't happen before the kill() but if it happens too > late after the victim passed its exit_mm() then process_release() > fails to find the mm to reap. This defeats the purpose of > process_release() call because the actual memory (released by > exit_mmap()) might not yet be free and a successful process_release() > would be very beneficial. > > I see these two as separate issues and I'm not sure combining them > into a single discussion is a good idea. > >> >> IIRC, Johannes raised in the past the we cannot predict the future. >> >> For example, if an app gets OOM-killed, wouldn't we usually try restarting it, >> re-consuming the clean pagecache pages we would be evicting here? > > Sure, we can't predict which app the user will use next, so when > killing we usually kill the least recently used one. That's a > reasonable strategy in most cases. That makes sense. As long as other apps you open next won't need the same libraries etc that you just evicted. -- Cheers, David