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AJvYcCXY7Fcni2ET3t4SWeVNPV/hb+M6tL/ViVWiXe2YNqskXb0ZWGma2dk3W6FGoJY93IaywMs0+j18kQ==@kvack.org X-Gm-Message-State: AOJu0YxguDEF2Zu3BeaTUbNfWZGA1avwkb1eEr+7L9JUNb+QkuPTck7V 74ZGUMH6uv7u2A/8QiQ2OvqbwS+Zp0+RMTMpn9wKdzno8ivREcGLS1WOt/qwa4lcSrXKxQfK8BZ 2JrwDK8WvS7DQpFLfIaoHQCMiF6WF/xrZnDRx X-Google-Smtp-Source: AGHT+IEpkyUPILcopb9spEmmNOJKOwpaXky/Jpzd8/ecb/9jPe0K0empPeLKdt9L4CjKeVSqvN+DMqH6lUtSvDsHlUw= X-Received: by 2002:a17:907:7e84:b0:a77:b784:deba with SMTP id a640c23a62f3a-a83928a416cmr886060466b.6.1724116040985; Mon, 19 Aug 2024 18:07:20 -0700 (PDT) MIME-Version: 1.0 References: <20240814171800.23558-1-me@yhndnzj.com> <20240815150819.9873910fa73a3f9f5e37ef4d@linux-foundation.org> <20240819180131.27b0ea66dd50b83c85102540@linux-foundation.org> In-Reply-To: <20240819180131.27b0ea66dd50b83c85102540@linux-foundation.org> From: Yosry Ahmed Date: Mon, 19 Aug 2024 18:06:43 -0700 Message-ID: Subject: Re: [PATCH] mm/memcontrol: respect zswap.writeback setting from parent cg too To: Andrew Morton Cc: Nhat Pham , Mike Yuan , linux-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, Muchun Song , Shakeel Butt , Roman Gushchin , Michal Hocko , Johannes Weiner Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 5F2321A0005 X-Stat-Signature: xw416u8bnhzk6et6pb6apc8gqzzf7ibj X-Rspamd-Server: rspam09 X-Rspam-User: X-HE-Tag: 1724116043-672696 X-HE-Meta: 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 DjlolcQ5 iJ8Ck3Mo9GbXilw8H21pTxXms19M/YchiDQnRYWnf7BDeHLAZOOxGZN9WNUNEnVKfQZWFaS0u4QpRZKUmk/zYzA1MtehyTXrG47lXrenCbvKnvtCk8xmBQTPtO6LR3cqY1Sx6hKm+INXJJtmOlnML4MGm05jtC0VxoETHCcFYYwLOsx2ePWy0S6vAwUAZk/5xlRU4Jijna2LVPr+Ufbe7FHPBp/B0OqwHtE/Eseen7+o/CeubKFImJZ8KwZ/xjtmrzfJ9 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 Mon, Aug 19, 2024 at 6:01=E2=80=AFPM Andrew Morton wrote: > > On Mon, 19 Aug 2024 12:05:44 -0700 Yosry Ahmed wr= ote: > > > > Ah yeah, I was thinking this could be done in a follow-up patch. > > > > > > But yes, please - documentation. Preferably everything together as v2= . > > > > > > > > > > > Also, do we want a Fixes tag and to backport this so that current > > > > users get the new behavior ASAP? > > > > > > Hmm, I wonder if it's more confusing for users to change the behavior > > > in older kernels. > > > > > > (OTOH, if this already is what people expect, then yeah it's a good > > > idea to backport). > > > > My rationale is that if people will inevitably get the behavior change > > when they upgrade their kernel, I'd rather they get it sooner rather > > than later, before more users start depending on the old behavior. > > > > I am guessing there is a chance this is not what backports are meant > > for. Andrew, any thoughts on this? > > I agree. It does depend on how long the old behavior has been out in > the field, and on our assessment of how many people are likely to > inconvenienced. So... yes please, what is that Fixes:? > It's commit 501a06fe8e4c ("zswap: memcontrol: implement zswap writeback disabling"). It landed in v6.8. I suspect there aren't many users that depend on the old behavior so far, so I would prefer to get this backported so that it's less likely that more (or any) users start depending on the old behavior.