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AJvYcCUI72xEdoQMTljhZJWSAYDP59XNS0VUdObB9NYj/4WPNztaUJayt/uODLSzuisaRq3LpDnn6Zk9wQ==@kvack.org X-Gm-Message-State: AOJu0Yy3xvytYjnHu+eW6fnLCHVkqPIvDER6ElRscmTnUrR1ZJXBxjza B9H7NLIMxcR0NZF1kr1R16Ce2EkVi25wsERv585/nKqrpCwsZ+Eu6CLQM0/cVtWVGTVSOwwLx0f A3njLMw0kfLu7N4vMzfO2Fbi37N5bSDL10Dmc6/xc1A== X-Gm-Gg: ASbGncs4ypA9U4beq1cwUHG2HR77dkq1RGjaXCseHD8v4uo7t4yZV9LmO3GjseUWVSw t0XA72H1Rbz7umCxuzA+RI4owgS2Ft3vPXfLe03GjCLYOZea6iwKQ/qZo5r4Tjldt8r7ROvzGdi ZRlWAJqrZRs+0cXlJvKtKrymAmP33Wi9NGDtBKM7IWF+HiiDGk7lY/xtMSnRcVaLnJ+m39zOhOX 00SZYLgTVzBGg5QW/ZsCB7Azl0SuEwVOH2NZn6v+xRym44HwvEBU+hFKg== X-Google-Smtp-Source: AGHT+IE6NyLe9C9FZki5iqhbn7SPAhloGhmZAVL7TcGQzvAGxu+qhhe6/PYG3PIh8YJQedsoxrgsfW8jKdq98CqxiHg= X-Received: by 2002:a05:6402:21d2:b0:641:7a6b:c84b with SMTP id 4fb4d7f45d1cf-64350eaa120mr2487306a12.27.1763129617993; Fri, 14 Nov 2025 06:13:37 -0800 (PST) MIME-Version: 1.0 References: <20251110180715.602807-1-pasha.tatashin@soleen.com> In-Reply-To: From: Pasha Tatashin Date: Fri, 14 Nov 2025 09:13:01 -0500 X-Gm-Features: AWmQ_bn2JTVcrMalLvDrtUy-789mrdL8UQfu0H53fSt1tKQevbBhJ-8H6gadkbQ Message-ID: Subject: Re: [PATCH] liveupdate: kho: Enable KHO by default To: Mike Rapoport Cc: akpm@linux-foundation.org, graf@amazon.com, pratyush@kernel.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 021FC1C0013 X-Stat-Signature: 1mpgctt6ks1ujxdzdr6y77yqbafqq7rk X-HE-Tag: 1763129619-795712 X-HE-Meta: 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 CVmlZa4t zumLNdjYeCCu/ds1we0Cq5Xm47sq7alyd993suo5uqrPw8XFcLoyosAP9T0mGl1xg6eGE4PyCGDXxmVjBnbzDuRLmyXIqKNUhYhugHsGUs+KkxAE6P+QI7fxPFWc58Juj44MgZ5FCWtegI/wLUX9U/Ah6Vvkgf/Bze/iwncR9oyWxXXHYgAe4w6KEEjMJBtUEL78dNG3iYbC6lUpa3BnbmAL8/sbjYytdJ6S2v73wXOA00lCu5H1ZnOt1Vb+/WmZy/EIQKXo9tAnnOLQ= 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 Fri, Nov 14, 2025 at 2:30=E2=80=AFAM Mike Rapoport wro= te: > > On Mon, Nov 10, 2025 at 01:07:15PM -0500, Pasha Tatashin wrote: > > Upcoming LUO requires KHO for its operations, the requirement to place > > both KHO=3Don and liveupdate=3Don becomes redundant. Set KHO to be enab= led > > by default. > > I though more about this and it seems too much of a change. kho=3D1 enabl= es > scratch areas and that significantly changes how free pages are distribut= ed > in the free lists. > > Let's go with a Kconfig option we discussed of-list: > (this is on top of the current mmotm/mm-nonmm-unstable) I will include this into the KHO simplification series > > From 823299d80aa4f7c16ef6cfd798a19e1dfe1a91ab Mon Sep 17 00:00:00 2001 > From: Pasha Tatashin > Date: Fri, 14 Nov 2025 09:27:47 +0200 > Subject: [PATCH] kho: Allow KHO to be enabled by default > > Upcoming LUO requires KHO for its operations, the requirement to place > both KHO=3Don and liveupdate=3Don becomes reduntant. Let's allow KHO to b= e > enabled by default, and CONFIG_LIVEUPDATE can select this CONFIG. > > Signed-off-by: Pasha Tatashin > Signed-off-by: Mike Rapoport (Microsoft) > --- > kernel/liveupdate/Kconfig | 8 ++++++++ > kernel/liveupdate/kexec_handover.c | 2 +- > 2 files changed, 9 insertions(+), 1 deletion(-) > > diff --git a/kernel/liveupdate/Kconfig b/kernel/liveupdate/Kconfig > index d7344d347f69..25c9a4d7781f 100644 > --- a/kernel/liveupdate/Kconfig > +++ b/kernel/liveupdate/Kconfig > @@ -63,4 +63,12 @@ config KEXEC_HANDOVER_DEBUGFS > Also, enables inspecting the KHO fdt trees with the debugfs bin= ary > blobs. > > +config KEXEC_HANDOVER_ENABLE_DEFAULT > + bool "Enable kexec handover by default" > + depends on KEXEC_HANDOVER > + help > + Enable the kexec handover by default. It is equivalent of passi= ng > + kho=3Don via kernel parameter, and can be overwritten to off vi= a > + kho=3Doff. > + > endmenu > diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec= _handover.c > index 568cd9fe9aca..23a3df297bb3 100644 > --- a/kernel/liveupdate/kexec_handover.c > +++ b/kernel/liveupdate/kexec_handover.c > @@ -51,7 +51,7 @@ union kho_page_info { > > static_assert(sizeof(union kho_page_info) =3D=3D sizeof(((struct page *)= 0)->private)); > > -static bool kho_enable __ro_after_init =3D true; > +static bool kho_enable __ro_after_init =3D IS_ENABLED(CONFIG_KEXEC_HANDO= VER_ENABLE_DEFAULT); > > bool kho_is_enabled(void) > { > -- > 2.50.1 > > > > -- > Sincerely yours, > Mike.