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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690898767; bh=cvHKNKef6GqmvaPlIs3cdxkwamcOD0XFqYJ3aWGoc6s=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=G9yyB3W84kuB9lMse2ogfGeBJ+xCGvAdOmzfDsfDo5zQEplsjwnFxP2ERGPAQ9AOV D62ZfC/fj1pKLSkUmFvcxa29DEeD41iuoBnNWBcl4zk16ZmCwkFarzeKantXfRzPSB kpqHwXrjDYyZrpwWiU/gFljgyFcGYUcqAl15e6KD9Qr5QjvecO7BXWuQKAE8PUFFiJ Rn+4lz1cBVHao6pHVObCXxKWbQurwrxQmiNRINWVdMrXYOUvnifOGjTt49gbM4bcHU KVbSVSNoZj8rYKSgptAwT0bpWlgaSnHgkyaTaduQv0lZGckI8MCIMPxOe+8rG5mOxc 6iFCufstc46nw== Date: Tue, 1 Aug 2023 17:05:25 +0300 From: Mike Rapoport To: Kefeng Wang Cc: Wupeng Ma , akpm@linux-foundation.org, linux-mm@kvack.org Subject: Re: [PATCH] mm: disable kernelcore=mirror when no mirror memory Message-ID: <20230801140525.GK1901145@kernel.org> References: <20230728040124.4093229-1-mawupeng1@huawei.com> <20230729081218.GH1901145@kernel.org> <20230730065353.GJ1901145@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: 7tgbnx3crs5bg5jttf6jsh4yomdia6jg X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 132874129B X-Rspam-User: X-HE-Tag: 1690909803-277325 X-HE-Meta: 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 NcEn0bVp bMpOxY/bD68I3FPXgfmLth9iDV6e/o7axxiO/QrrXhY7nHmWsNy5LnXW8dvKJV7pJyYLadESBYO0MKz/rlz14O1L0DCK/k70G2zCn6JbdnEJzNauywTgJE/d/v4bLI3Z36j/7STXqVeQLMsKhONJU2kKUJptyBOc07O/RsbzUqpTYTT70wsXI5XH3T/CDL+Th0MXr94SFdlMblTZ0BA7OHwVz3Kk8ZRbuyvP/4S8olKQsDR0y5BRuDxWxjrfyBk5oApf3/A328RBWVyx5coymN/CI41zbVUEgc3rlw35+hJgjYsxpntyNhZjdeA== 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 Mon, Jul 31, 2023 at 09:39:37AM +0800, Kefeng Wang wrote: > > On 2023/7/30 14:53, Mike Rapoport wrote: > > On Sat, Jul 29, 2023 at 04:57:17PM +0800, Kefeng Wang wrote: > > > > > > > > > On 2023/7/29 16:12, Mike Rapoport wrote: > > > > On Fri, Jul 28, 2023 at 12:01:24PM +0800, Wupeng Ma wrote: > > > > > From: Ma Wupeng > > > > > > > > > > For system with kernelcore=mirror enabled while no mirrored memory is > > > > > reported by efi. This could lead to kernel OOM during startup since > > > > > all memory beside zone DMA are in the movable zone and this prevents > > > > > the kernel to use it. > > > > > > > > > > Zone DMA/DMA32 initialization is independent of mirrored memory and > > > > > their max pfn is set in zone_sizes_init(). Since kernel can fallback > > > > > to zone DMA/DMA32 if there is no memory in zone Normal, these zones > > > > > are seen as mirrored memory no mather their memory attributes are. > > > > > > > > Using kernelcore= and movablecore= always come with the risk there will be > > > > to little memory for the kernel to use. Even if EFI reports mirrored memory > > > > it's possible to have OOM with kernelcore=mirror because there could be > > > > just not enough mirrored memory. > > > > > > > > > Only x86/arm64 support kernelcore=mirror, system_has_some_mirror is > > > false by default, so it should no issue for now, but it is better to > > > move this check into find_zone_movable_pfns_for_nodes(). > > > > Sorry, I meant that system_has_some_mirror is false by default, and both > > x86/arm64 parse early parameters before they set up memblock, so > > system_has_some_mirror will be always false at this point. > > Clear, so let's move check into find_zone_movable_pfns_for_nodes()(no test), > is this ok? This looks fine to me, just one nit below. > diff --git a/mm/internal.h b/mm/internal.h > index a7d9e980429a..1599becc9079 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -1005,6 +1005,7 @@ static inline bool gup_must_unshare(struct > vm_area_struct *vma, > } > > extern bool mirrored_kernelcore; > +extern bool system_has_some_mirror; I prefer keeping system_has_some_mirror static and adding, say, memblock_has_mirror(). > static inline bool vma_soft_dirty_enabled(struct vm_area_struct *vma) > { > diff --git a/mm/memblock.c b/mm/memblock.c > index f9e61e565a53..e7a7a65415fb 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -156,10 +156,10 @@ static __refdata struct memblock_type *memblock_memory > = &memblock.memory; > } while (0) > > static int memblock_debug __initdata_memblock; > -static bool system_has_some_mirror __initdata_memblock; > static int memblock_can_resize __initdata_memblock; > static int memblock_memory_in_slab __initdata_memblock; > static int memblock_reserved_in_slab __initdata_memblock; > +bool system_has_some_mirror __initdata_memblock; > > static enum memblock_flags __init_memblock choose_memblock_flags(void) > { > diff --git a/mm/mm_init.c b/mm/mm_init.c > index a1963c3322af..c444da6065a6 100644 > --- a/mm/mm_init.c > +++ b/mm/mm_init.c > @@ -377,6 +377,11 @@ static void __init > find_zone_movable_pfns_for_nodes(void) > if (mirrored_kernelcore) { > bool mem_below_4gb_not_mirrored = false; > > + if (!system_has_some_mirror) { > + pr_warn("The system has no mirror memory, ignore kernelcore=mirror.\n"); > + goto out; > + } > + > for_each_mem_region(r) { > if (memblock_is_mirror(r)) > continue; > -- Sincerely yours, Mike.