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From: Muchun Song In-Reply-To: <20230825111836.1715308-4-usama.arif@bytedance.com> Date: Mon, 28 Aug 2023 15:26:17 +0800 Cc: Linux-MM , Mike Kravetz , Mike Rapoport , linux-kernel@vger.kernel.org, Muchun Song , fam.zheng@bytedance.com, liangma@liangbit.com, punit.agrawal@bytedance.com Content-Transfer-Encoding: quoted-printable Message-Id: <357EEE41-1898-4430-BCC7-73F591CE8749@linux.dev> References: <20230825111836.1715308-1-usama.arif@bytedance.com> <20230825111836.1715308-4-usama.arif@bytedance.com> To: Usama Arif X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: D43DF160008 X-Stat-Signature: 8t4poec6fw4c67owbrn335nkssn1cmj9 X-Rspam-User: X-HE-Tag: 1693207624-874022 X-HE-Meta: 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 FmxmGJyA zVfjMwfdX+kBi+2GRij20wBGPMG6XZnUbB8UnsRA2PY4B+00azNlJGi7M97zJqWOe0LDmgfe23ThntlTU584/7ohWkYnknjugr81udAW/V9+J3GivaX3tO/VyqmnfcAGWI4G2YSXpAJBEUaghu1IVHK37TRszPxfKIxBhuvSZzndFK+McNZRW7P1+GWEFpzCrXcuZRaa+muDEgzUQP//nf5xYaOM38RKqWIErKeEeJ+lSAGNk6cy8MXRsvcNbBOVsI3H8 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: > On Aug 25, 2023, at 19:18, Usama Arif = wrote: >=20 > For reserved memory regions marked with this flag, > reserve_bootmem_region is not called during = memmap_init_reserved_pages. > This can be used to avoid struct page initialization for > regions which won't need them, for e.g. hugepages with > HVO enabled. >=20 > Signed-off-by: Usama Arif Reviewed-by: Muchun Song One nit below. > --- > include/linux/memblock.h | 10 ++++++++++ > mm/memblock.c | 32 +++++++++++++++++++++++++++----- > 2 files changed, 37 insertions(+), 5 deletions(-) >=20 > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > index f71ff9f0ec81..6d681d053880 100644 > --- a/include/linux/memblock.h > +++ b/include/linux/memblock.h > @@ -40,6 +40,8 @@ extern unsigned long long max_possible_pfn; > * via a driver, and never indicated in the firmware-provided memory = map as > * system RAM. This corresponds to IORESOURCE_SYSRAM_DRIVER_MANAGED in = the > * kernel resource tree. > + * @MEMBLOCK_RSRV_NOINIT_VMEMMAP: memory region for which struct = pages are > + * not initialized (only for reserved regions). We have a more detailed explanation here. > */ > enum memblock_flags { > MEMBLOCK_NONE =3D 0x0, /* No special request */ > @@ -47,6 +49,8 @@ enum memblock_flags { > MEMBLOCK_MIRROR =3D 0x2, /* mirrored region */ > MEMBLOCK_NOMAP =3D 0x4, /* don't add to kernel direct mapping */ > MEMBLOCK_DRIVER_MANAGED =3D 0x8, /* always detected via a driver = */ > + /* don't initialize struct pages associated with this reserver = memory block */ Those comments right after the macros here seem like a brief = explanation. To keep the consistent with others, maybe "don't initialize struct = pages" is enough? At least, a detailed one is redundant and repetitive compared with the above one. > + MEMBLOCK_RSRV_NOINIT_VMEMMAP =3D 0x10, > };