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Szmigiero" Cc: Andrew Morton , Nhat Pham , Chengming Zhou , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Johannes Weiner Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: E7928A000D X-Stat-Signature: f3xdmdok4sb16nyu37kmkfttx5kxzn7i X-HE-Tag: 1711996202-90525 X-HE-Meta: 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 jlw1H1bp 3Bp5mxkRnlZGyZP2vxenloueD0yVCim1dRkV8tlI2PSC1bRHbgJFxuiFthglhHqNvi1yhyGVf2aFJzm+FClMXbuPNMn3PGbuh/ApG/lwH3qPbcCfkkjRkK5sJmrZwKOibSvIthMiW41JQ2m1+FHfmuZDO9w2vIX0BeIotPt6p237C3AB5CPFzMoqVPjS6T2emqNz0uGRCLGGyBfXWpzxvtxMYftEoqitm+9x9wWelyn6/x5Lx2qAh1Ym3Hehal71NTiAx3W4WbiCuZX0qCjgad3OraXi3BSu2hrhVlQqYmacHewAjni9jjLY+l3winV4Y1QuYx+LdcYLs9DLUrixN+AlxY8ygPgX1X4ZOb6x813KSv7hzpis7t+68Q3K+Uu4ZnGl8g/avY9qHeli2IMHYpW+KNMrc91/sAHIV3DgFG+RfJcTiEdoDqEygJQ== 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, Apr 1, 2024 at 3:38=E2=80=AFAM Maciej S. Szmigiero wrote: > > On 29.03.2024 19:22, Yosry Ahmed wrote: > > On Fri, Mar 29, 2024 at 10:45=E2=80=AFAM Johannes Weiner wrote: > >> > >> On Fri, Mar 29, 2024 at 03:02:10PM +0100, Maciej S. Szmigiero wrote: > >>> On 29.03.2024 03:14, Yosry Ahmed wrote: > >>>> On Thu, Mar 28, 2024 at 1:06=E2=80=AFPM Yosry Ahmed wrote: > >>>>> > >>>>> On Thu, Mar 28, 2024 at 12:11=E2=80=AFPM Johannes Weiner wrote: > >>>>>> > >>>>>> On Mon, Mar 25, 2024 at 11:50:13PM +0000, Yosry Ahmed wrote: > >>>>>>> There is no logical reason to refuse storing same-filled pages mo= re > >>>>>>> efficiently and opt for compression. Remove the userspace knob. > >>>>>>> > >>>>>>> Signed-off-by: Yosry Ahmed > >>>>>> > >>>>>> Acked-by: Johannes Weiner > >>>>>> > >>>>>> I also think the non_same_filled_pages_enabled option should go > >>>>>> away. Both of these tunables are pretty bizarre. > >>>>> > >>>>> Happy to remove both in the next version :) > >>>> > >>>> I thought non_same_filled_pages_enabled was introduced with the > >>>> initial support for same-filled pages, but it was introduced > >>>> separately (and much more recently): > >>>> https://lore.kernel.org/all/7dbafa963e8bab43608189abbe2067f4b9287831= .1641247624.git.maciej.szmigiero@oracle.com/ > >>>> > >>>> I am CCing Maciej to hear more about the use case for this. > >>> > >>> Thanks for CCing me. > >>> > >>> I introduced "non_same_filled_pages_enabled" a few years ago to > >>> enable using zswap in a lightweight mode where it is only used for > >>> its ability to store same-filled pages effectively. > >> > >> But all the pages it rejects go to disk swap instead, which is much > >> slower than compression... > >> > >>> As far as I remember, there were some interactions between full > >>> zswap and the cgroup memory controller - like, it made it easier > >>> for an aggressive workload to exceed its cgroup memory.high limits. > >> > >> Ok, that makes sense! A container fairness measure, rather than a > >> performance optimization. > >> > >> Fair enough, but that's moot then with cgroup accounting of the > >> backing memory, f4840ccfca25 ("zswap: memcg accounting"). > > > > Right, this should no longer be needed with the zswap charging. > > > > Maciej, is this still being used on kernels with f4840ccfca25 (5.19+)? > > Any objections to removing it now? > > I don't object to its removal as long as stable kernel trees aren't > affected. Yeah this isn't something that would be backported to stable kernels. Thanks for confirming.