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h=Date:From:To:Cc:Subject:References:In-Reply-To; b=F4W1bQei0WbJqW4r8EVplbGGhiwx7NXzD9fjTAJz1nnroqL5YVOgqQUiArkdtmHyr W9CUxLppulp2QWgWTUWbd/dAehRrSW/lkzZ8oqUe3f2GoaBZ9mxErL6fLMqXM7hUoW pflbnHmqkcZuRmlsQGGEHcLyopvAXc13ZfvUKI6JKD4iUk+a26j861qNbyRs7NwWAe 5rxSiPFeIPanXD5TpncL4/J1QB4XlrZSZXGeFurkupyx3dvKksXmU0uWgTWfiWByEt kIY5KOkGCC+OaHU6gMgpAmJdMdOpQb8sI62v9yK0E5VZLKYJBnSZK7nFcRXx41rwCe CYxurd2l460hw== Date: Sat, 19 Sep 2026 10:11:24 +0300 From: Mike Rapoport To: Baoquan He Cc: Wandun Chen , catalin.marinas@arm.com, will@kernel.org, chenhuacai@kernel.org, pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, robh@kernel.org, saravanak@kernel.org, akpm@linux-foundation.org, pasha.tatashin@soleen.com, pratyush@kernel.org, m.szyprowski@samsung.com, mark.rutland@arm.com, kernel@xen0n.name, alex@ghiti.fr, hpa@zytor.com, ruirui.yang@linux.dev, robin.murphy@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, kexec@lists.infradead.org, linux-mm@kvack.org, iommu@lists.linux.dev Subject: Re: [PATCH v6 06/10] memblock: introduce MEMBLOCK_NODUMP flag Message-ID: References: <20260902073116.802752-1-chenwandun1@gmail.com> <20260902073116.802752-7-chenwandun1@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 84FF5C0005 X-Rspam-User: X-Stat-Signature: kdir7mmksuuiudpssedjpuj4y5fhy9hc X-HE-Tag: 1789801896-649572 X-HE-Meta: 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 sbB3PU8N rARqYYWDXxTE460FvZKawY3hQixCjTYIXelYlTVGgfp3uZf8Gb94E6yNZxNnpemKpDYEfcDRxaEyOejAFENkSoNvm0kR02pagv85eUtFt+4SfOXSD4ccul/F7ko5JKePjcTnEKiIjPf/nhIsXGNjq5pVPuvrBBvGht0M5u0zIuZ7igbl5s70chSQnHmg4bA8+/ieQ7izBCq/XFlgd6ykqLVidovWt8qrc5aqnFww5Mlb/pBPt1AIvxklpSoEsIxgnwADICrUVUIoV5BLqyPoELhWBsREnysmNiCJaDP4EauQhtkoSwcN915E/4/GTh/jUrcvShfAoNKYhBpHRJnZpjfoJcFXAGx3NJ7lgUpyTBg6uAWMhQF0gyOf3D9T1zD5iTPMQ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Sep 18, 2026 at 04:08:10PM +0800, Baoquan He wrote: > On 09/02/26 at 03:31pm, Wandun Chen wrote: > > From: Wandun Chen > > > > Add MEMBLOCK_NODUMP to mark regions that should be excluded from > > kdump vmcores. > > > > The flag is meant for reserved memory that carries no data useful for > > crash analysis. Reusable reserved regions such as CMA may hold useful > > data, so these regions must not be marked MEMBLOCK_NODUMP. Subsequent > > patches wire this up for /reserved-memory and /memreserve/ entries. > > > > Suggested-by: Rob Herring > > Signed-off-by: Wandun Chen > > Tested-by: Meijing Zhao > > --- > > include/linux/memblock.h | 9 +++++++++ > > mm/memblock.c | 16 ++++++++++++++++ > > 2 files changed, 25 insertions(+) > > > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > > index d62db9e776cf..b2fcf11fba2b 100644 > > --- a/include/linux/memblock.h > > +++ b/include/linux/memblock.h > > @@ -52,6 +52,8 @@ extern unsigned long long max_possible_pfn; > > * kernel that we know is good to use. It is the only memory that > > * allocations may happen from in this phase. > > * @MEMBLOCK_RSRV_HUGETLB: memory is reserved for hugetlb pages > > + * @MEMBLOCK_NODUMP: exclude from kdump vmcore. It carries no data useful > > + * for crash analysis (e.g. firmware carveouts). > > */ > > enum memblock_flags { > > MEMBLOCK_NONE = 0x0, /* No special request */ > > @@ -63,6 +65,7 @@ enum memblock_flags { > > MEMBLOCK_RSRV_KERN = 0x20, /* memory reserved for kernel use */ > > MEMBLOCK_KHO_SCRATCH = 0x40, /* scratch memory for kexec handover */ > > MEMBLOCK_RSRV_HUGETLB = 0x80, /* memory reserved for hugetlb pages */ > > + MEMBLOCK_NODUMP = 0x100,/* exclude from kdump vmcore */ > > }; > > > > /** > > @@ -160,6 +163,7 @@ int memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t size); > > int memblock_reserved_mark_kern(phys_addr_t base, phys_addr_t size); > > int memblock_mark_kho_scratch(phys_addr_t base, phys_addr_t size); > > int memblock_clear_kho_scratch(phys_addr_t base, phys_addr_t size); > > +int memblock_mark_nodump(phys_addr_t base, phys_addr_t size); > > > > void memblock_free(void *ptr, size_t size); > > void reset_all_zones_managed_pages(void); > > @@ -306,6 +310,11 @@ static inline bool memblock_is_kho_scratch(struct memblock_region *m) > > return m->flags & MEMBLOCK_KHO_SCRATCH; > > } > > > > +static inline bool memblock_is_nodump(struct memblock_region *m) > > +{ > > + return m->flags & MEMBLOCK_NODUMP; > > +} > > + > > int memblock_search_pfn_nid(unsigned long pfn, unsigned long *start_pfn, > > unsigned long *end_pfn); > > void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn, > > diff --git a/mm/memblock.c b/mm/memblock.c > > index f2952d725c10..2e87f39826dd 100644 > > --- a/mm/memblock.c > > +++ b/mm/memblock.c > > @@ -1204,6 +1204,21 @@ __init int memblock_clear_kho_scratch(phys_addr_t base, phys_addr_t size) > > MEMBLOCK_KHO_SCRATCH); > > } > > > > +/** > > + * memblock_mark_nodump - Mark a memory region with flag MEMBLOCK_NODUMP. > > + * @base: the base phys addr of the region > > + * @size: the size of the region > > + * > > + * Mark the region as not to be included in crash dumps. > > + * > > + * Return: 0 on success, -errno on failure. > > + */ > > +int __init_memblock memblock_mark_nodump(phys_addr_t base, phys_addr_t size) > ~~~~~~~~~~~~~~^ > Is it impossible to use at runtime even thought it claims to be generic? This should only happen at boot. Allowing modifications of memblock properties in runtime is a can of worms I don't want to open. > > +{ > > + return memblock_setclr_flag(&memblock.memory, base, size, 1, > > + MEMBLOCK_NODUMP); > > +} > > + > > static bool should_skip_region(struct memblock_type *type, > > struct memblock_region *m, > > int nid, int flags) > > @@ -2887,6 +2902,7 @@ static const char * const flagname[] = { > > [ilog2(MEMBLOCK_RSRV_KERN)] = "RSV_KERN", > > [ilog2(MEMBLOCK_KHO_SCRATCH)] = "KHO_SCRATCH", > > [ilog2(MEMBLOCK_RSRV_HUGETLB)] = "RSV_HUGETLB", > > + [ilog2(MEMBLOCK_NODUMP)] = "NODUMP", > > }; > > > > static int memblock_debug_show(struct seq_file *m, void *private) > > -- > > 2.43.0 > > -- Sincerely yours, Mike.