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c=relaxed/simple; d=kernel.org; s=k20201202; t=1694001753; bh=q+ygTF8Sz49mjT86dwdndFEl1wHyqfAEeqoYnTLNyGk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Z4gSYhhWb41sEFzjBM4Wa0QAmG9tJCgHQyQwwJDbQ90H9pFR8n88pnukSZjfn3u3y fIH3EuX15fHKYDtmPPkQ3sVPSz9/yWvOMVZcWpdmGwfUP0Pu59lK6QnQpPXiA4Zn83 /D7NlBucE73BK5jVzcygsJzUUT0ZJZQ07Xlfi6WhgxE/WON7h+VjeKXIoyXW1KSdz5 7rInuyy5Cp29Q2JHf/Gi+jX/3onWjHnyP4t5RQVoGHKfTFGsq/u7kUdHLIYDDwU2ON ooUqPBi0XuPMlPDEiZyEdgCrEJRyL28dtd8YNV7wjoDxjtyQLg0zybLNJE8vwH/+j6 mvwh4l84d+/ZA== Date: Wed, 6 Sep 2023 15:01:48 +0300 From: Mike Rapoport To: Usama Arif Cc: linux-mm@kvack.org, muchun.song@linux.dev, mike.kravetz@oracle.com, linux-kernel@vger.kernel.org, songmuchun@bytedance.com, fam.zheng@bytedance.com, liangma@liangbit.com, punit.agrawal@bytedance.com Subject: Re: [v4 3/4] memblock: introduce MEMBLOCK_RSRV_NOINIT flag Message-ID: <20230906120148.GJ3223@kernel.org> References: <20230906112605.2286994-1-usama.arif@bytedance.com> <20230906112605.2286994-4-usama.arif@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230906112605.2286994-4-usama.arif@bytedance.com> X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 4B26540014 X-Stat-Signature: 7da7neqa1pkbdnjq64jscaongeis9uau X-Rspam-User: X-HE-Tag: 1694001758-166105 X-HE-Meta: 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 v1od6FJp +LNDKw8zGxCH1SK9Ze5u+u4RmrwYkZs+81jA18qAXtsu8vYWoaFz7DKriaJdd9W46l2g5THiTVqx7AJgJatKlu+lLWI2G71Iid8Nrr93ewl7LTks0G7s2LuyyFes1WWl32NVAEYKeO4f6TcV/vUPP0kzvqKSY7uovNLYXyprtwzNplHaG0cxBThPa87Tu0m1ZpCf5xhn+O8z8X3ocEZDaCEM1xEvSoz/1FPycPTQRaDth7gtEz+hTvlJj/OGwewboWDsUvQgtcCcDLL0B2hbE/jMDfJN5FEnpNx9cqbYVS877NZSii8V8UGJG4DtXegdkwWI3WVwvrW0I+/GYmWBgj4ULtG8yfBVUniSJx0emcaARugVuuS1QOEIo16B13PXMCoJrcIAoyhiTWLYxjZf/3NgD7EsJWB2A+WjUnHv7KXFiSvxkN497/rwObYx2Z2o8N4s0KV9sarijz+Q= 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 Wed, Sep 06, 2023 at 12:26:04PM +0100, Usama Arif wrote: > 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. Nit: please spell out HVO, otherwise > Signed-off-by: Usama Arif Reviewed-by: Mike Rapoport (IBM) > --- > include/linux/memblock.h | 9 +++++++++ > mm/memblock.c | 33 ++++++++++++++++++++++++++++----- > 2 files changed, 37 insertions(+), 5 deletions(-) > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > index 1c1072e3ca06..ae3bde302f70 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: memory region for which struct pages are > + * not initialized (only for reserved regions). > */ > enum memblock_flags { > MEMBLOCK_NONE = 0x0, /* No special request */ > @@ -47,6 +49,7 @@ enum memblock_flags { > MEMBLOCK_MIRROR = 0x2, /* mirrored region */ > MEMBLOCK_NOMAP = 0x4, /* don't add to kernel direct mapping */ > MEMBLOCK_DRIVER_MANAGED = 0x8, /* always detected via a driver */ > + MEMBLOCK_RSRV_NOINIT = 0x10, /* don't initialize struct pages */ > }; > > /** > @@ -125,6 +128,7 @@ int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size); > int memblock_mark_mirror(phys_addr_t base, phys_addr_t size); > int memblock_mark_nomap(phys_addr_t base, phys_addr_t size); > int memblock_clear_nomap(phys_addr_t base, phys_addr_t size); > +int memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t size); > > void memblock_free_all(void); > void memblock_free(void *ptr, size_t size); > @@ -259,6 +263,11 @@ static inline bool memblock_is_nomap(struct memblock_region *m) > return m->flags & MEMBLOCK_NOMAP; > } > > +static inline bool memblock_is_reserved_noinit(struct memblock_region *m) > +{ > + return m->flags & MEMBLOCK_RSRV_NOINIT; > +} > + > static inline bool memblock_is_driver_managed(struct memblock_region *m) > { > return m->flags & MEMBLOCK_DRIVER_MANAGED; > diff --git a/mm/memblock.c b/mm/memblock.c > index a49efbaee7e0..8f7a0cb668d4 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -996,6 +996,24 @@ int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size) > return memblock_setclr_flag(&memblock.memory, base, size, 0, MEMBLOCK_NOMAP); > } > > +/** > + * memblock_reserved_mark_noinit - Mark a reserved memory region with flag > + * MEMBLOCK_RSRV_NOINIT which results in the struct pages not being initialized > + * for this region. > + * @base: the base phys addr of the region > + * @size: the size of the region > + * > + * struct pages will not be initialized for reserved memory regions marked with > + * %MEMBLOCK_RSRV_NOINIT. > + * > + * Return: 0 on success, -errno on failure. > + */ > +int __init_memblock memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t size) > +{ > + return memblock_setclr_flag(&memblock.reserved, base, size, 1, > + MEMBLOCK_RSRV_NOINIT); > +} > + > static bool should_skip_region(struct memblock_type *type, > struct memblock_region *m, > int nid, int flags) > @@ -2112,13 +2130,18 @@ static void __init memmap_init_reserved_pages(void) > memblock_set_node(start, end, &memblock.reserved, nid); > } > > - /* initialize struct pages for the reserved regions */ > + /* > + * initialize struct pages for reserved regions that don't have > + * the MEMBLOCK_RSRV_NOINIT flag set > + */ > for_each_reserved_mem_region(region) { > - nid = memblock_get_region_node(region); > - start = region->base; > - end = start + region->size; > + if (!memblock_is_reserved_noinit(region)) { > + nid = memblock_get_region_node(region); > + start = region->base; > + end = start + region->size; > > - reserve_bootmem_region(start, end, nid); > + reserve_bootmem_region(start, end, nid); > + } > } > } > > -- > 2.25.1 > -- Sincerely yours, Mike.