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b=rq46MTa6E0BZ7P6nDMGVHEIbqrT6a/+4vxnV3EWD+gk1kkiul2VBJcj2srNAhI2cM BW10h4l1E1kHdzFRlLa2Ltn3kO9sPFHN5kHpR5qkNCox7dCislZrvCIUfaSMwsErPm MpPwSzA5zgropOxblSm5gTHS6+dUOpzIZqDtgWXI= Date: Thu, 30 Nov 2023 13:33:40 -0800 From: Andrew Morton To: Dan Schatzberg Cc: Johannes Weiner , Roman Gushchin , Yosry Ahmed , Huan Yang , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, Michal Hocko , Shakeel Butt , Muchun Song , David Hildenbrand , Matthew Wilcox , Huang Ying , Kefeng Wang , Peter Xu , "Vishal Moola (Oracle)" , Yue Zhao , Hugh Dickins Subject: Re: [PATCH 1/1] mm: add swapiness= arg to memory.reclaim Message-Id: <20231130133340.36140526608289898acb3ac5@linux-foundation.org> In-Reply-To: <20231130153658.527556-2-schatzberg.dan@gmail.com> References: <20231130153658.527556-1-schatzberg.dan@gmail.com> <20231130153658.527556-2-schatzberg.dan@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 3878DC001F X-Rspam-User: X-Stat-Signature: jnsob9s5bo5dbudur6u33rofca1jdbww X-Rspamd-Server: rspam01 X-HE-Tag: 1701380025-84637 X-HE-Meta: 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 gZVbdrf8 3Eu/mOvrXWx/W5mTZBGILh3o8bfQw3FRqrLoszyZbf2yChbQXrLej2+Kv/F+12B2ynXguSRarMdpNfBmo4/UYV1qcKVNZr1c67AU/W/J6uCqvUCHG9+R98/0pxpMXh0vGUGXdaj0+ym1sFTzt0PEYdkW9qNR1H1GE1Ty0vlhUog8F7q0cWe/+jPUiV/EUNMD0Q+2ahzb4hHVqCWG26KvQNEJldQGo2dB7z2JuxUIsLRRew/0SKDWLQ67OunfgR+UIvNC13wgqyzcFvFdZrs6E0GeGYwHgC2lEGOsGZ1meTsYlO52+zDMLsuxRBCgAz2NLMpwUgg3R/gfgtj0TndsgQnZ5114l0w8J+VDfK9cHNB7/YqeeTgsDs/F7tg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 30 Nov 2023 07:36:54 -0800 Dan Schatzberg wrote: > Allow proactive reclaimers to submit an additional swappiness= > argument to memory.reclaim. This overrides the global or per-memcg > swappiness setting for that reclaim attempt. > > For example: > > echo "2M swappiness=0" > /sys/fs/cgroup/memory.reclaim > > will perform reclaim on the rootcg with a swappiness setting of 0 (no > swap) regardless of the vm.swappiness sysctl setting. > > Signed-off-by: Dan Schatzberg > --- > include/linux/swap.h | 3 ++- > mm/memcontrol.c | 55 +++++++++++++++++++++++++++++++++++--------- > mm/vmscan.c | 13 +++++++++-- Documentation/admin-guide/cgroup-v2.rst is feeling unloved! Please check whether this interface change can lead to non-backward-compatible userspace. If someone's script does the above echo command, will it break on older kernels? If so, does it matter?