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Message-ID: <20130905133027.GA23038@hacker.(null)> Reply-To: Wanpeng Li References: <1377596268-31552-1-git-send-email-tangchen@cn.fujitsu.com> <1377596268-31552-11-git-send-email-tangchen@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1377596268-31552-11-git-send-email-tangchen@cn.fujitsu.com> Sender: owner-linux-mm@kvack.org List-ID: To: Tang Chen Cc: rjw@sisk.pl, lenb@kernel.org, tglx@linutronix.de, mingo@elte.hu, hpa@zytor.com, akpm@linux-foundation.org, tj@kernel.org, trenn@suse.de, yinghai@kernel.org, jiang.liu@huawei.com, wency@cn.fujitsu.com, laijs@cn.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, izumi.taku@jp.fujitsu.com, mgorman@suse.de, minchan@kernel.org, mina86@mina86.com, gong.chen@linux.intel.com, vasilis.liaskovitis@profitbricks.com, lwoodman@redhat.com, riel@redhat.com, jweiner@redhat.com, prarit@redhat.com, zhangyanfei@cn.fujitsu.com, x86@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-acpi@vger.kernel.org Hi Tang, On Tue, Aug 27, 2013 at 05:37:47PM +0800, Tang Chen wrote: >init_mem_mapping() is called before SRAT is parsed. And memblock will allocate >memory for page tables. To prevent page tables being allocated within hotpluggable >memory, we will allocate page tables from the end of kernel image to the higher >memory. > >The order of page tables allocation is controled by movablenode boot option. >Since the default behavior of page tables initialization procedure is allocate >page tables from top of the memory downwards, if users don't specify movablenode >boot option, the kernel will behave as before. > >Signed-off-by: Tang Chen >Reviewed-by: Zhang Yanfei >--- > arch/x86/mm/init.c | 119 +++++++++++++++++++++++++++++++++++++++------------ > 1 files changed, 91 insertions(+), 28 deletions(-) > >diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c >index 793204b..f004d8e 100644 >--- a/arch/x86/mm/init.c >+++ b/arch/x86/mm/init.c >@@ -407,13 +407,77 @@ static unsigned long __init init_range_memory_mapping( > > /* (PUD_SHIFT-PMD_SHIFT)/2 */ > #define STEP_SIZE_SHIFT 5 >-void __init init_mem_mapping(void) >+ >+#ifdef CONFIG_MOVABLE_NODE >+/** >+ * memory_map_from_low - Map [start, end) from low to high >+ * @start: start address of the target memory range >+ * @end: end address of the target memory range >+ * >+ * This function will setup direct mapping for memory range [start, end) in a >+ * heuristic way. In the beginning, step_size is small. The more memory we map >+ * memory in the next loop. >+ */ >+static void __init memory_map_from_low(unsigned long start, unsigned long end) >+{ >+ unsigned long next, new_mapped_ram_size; >+ unsigned long mapped_ram_size = 0; >+ /* step_size need to be small so pgt_buf from BRK could cover it */ >+ unsigned long step_size = PMD_SIZE; >+ >+ while (start < end) { >+ if (end - start > step_size) { >+ next = round_up(start + 1, step_size); >+ if (next > end) >+ next = end; >+ } else >+ next = end; >+ >+ new_mapped_ram_size = init_range_memory_mapping(start, next); >+ start = next; >+ >+ if (new_mapped_ram_size > mapped_ram_size) >+ step_size <<= STEP_SIZE_SHIFT; >+ mapped_ram_size += new_mapped_ram_size; >+ } >+} >+#endif /* CONFIG_MOVABLE_NODE */ >+ >+/** >+ * memory_map_from_high - Map [start, end) from high to low >+ * @start: start address of the target memory range >+ * @end: end address of the target memory range >+ * >+ * This function is similar to memory_map_from_low() except it maps memory >+ * from high to low. >+ */ >+static void __init memory_map_from_high(unsigned long start, unsigned long end) > { >- unsigned long end, real_end, start, last_start; >- unsigned long step_size; >- unsigned long addr; >+ unsigned long prev, new_mapped_ram_size; > unsigned long mapped_ram_size = 0; >- unsigned long new_mapped_ram_size; >+ /* step_size need to be small so pgt_buf from BRK could cover it */ >+ unsigned long step_size = PMD_SIZE; >+ >+ while (start < end) { >+ if (end > step_size) { >+ prev = round_down(end - 1, step_size); >+ if (prev < start) >+ prev = start; >+ } else >+ prev = start; >+ >+ new_mapped_ram_size = init_range_memory_mapping(prev, end); >+ end = prev; >+ >+ if (new_mapped_ram_size > mapped_ram_size) >+ step_size <<= STEP_SIZE_SHIFT; >+ mapped_ram_size += new_mapped_ram_size; >+ } >+} >+ >+void __init init_mem_mapping(void) >+{ >+ unsigned long end; > > probe_page_size_mask(); > >@@ -423,44 +487,43 @@ void __init init_mem_mapping(void) > end = max_low_pfn << PAGE_SHIFT; > #endif > >- /* the ISA range is always mapped regardless of memory holes */ >- init_memory_mapping(0, ISA_END_ADDRESS); >+ max_pfn_mapped = 0; /* will get exact value next */ >+ min_pfn_mapped = end >> PAGE_SHIFT; >+ >+#ifdef CONFIG_MOVABLE_NODE >+ unsigned long kernel_end; >+ >+ if (movablenode_enable_srat && >+ memblock.current_order == MEMBLOCK_ORDER_LOW_TO_HIGH) { I think memblock.current_order == MEMBLOCK_ORDER_LOW_TO_HIGH is always true if config MOVABLE_NODE and movablenode_enable_srat == true if PATCH 11/11 is applied. >+ kernel_end = round_up(__pa_symbol(_end), PMD_SIZE); >+ >+ memory_map_from_low(kernel_end, end); >+ memory_map_from_low(ISA_END_ADDRESS, kernel_end); Why split ISA_END_ADDRESS ~ end? >+ goto out; >+ } >+#endif /* CONFIG_MOVABLE_NODE */ >+ >+ unsigned long addr, real_end; > > /* xen has big range in reserved near end of ram, skip it at first.*/ > addr = memblock_find_in_range(ISA_END_ADDRESS, end, PMD_SIZE, PMD_SIZE); > real_end = addr + PMD_SIZE; > >- /* step_size need to be small so pgt_buf from BRK could cover it */ >- step_size = PMD_SIZE; >- max_pfn_mapped = 0; /* will get exact value next */ >- min_pfn_mapped = real_end >> PAGE_SHIFT; >- last_start = start = real_end; >- > /* > * We start from the top (end of memory) and go to the bottom. > * The memblock_find_in_range() gets us a block of RAM from the > * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages > * for page table. > */ >- while (last_start > ISA_END_ADDRESS) { >- if (last_start > step_size) { >- start = round_down(last_start - 1, step_size); >- if (start < ISA_END_ADDRESS) >- start = ISA_END_ADDRESS; >- } else >- start = ISA_END_ADDRESS; >- new_mapped_ram_size = init_range_memory_mapping(start, >- last_start); >- last_start = start; >- /* only increase step_size after big range get mapped */ >- if (new_mapped_ram_size > mapped_ram_size) >- step_size <<= STEP_SIZE_SHIFT; >- mapped_ram_size += new_mapped_ram_size; >- } I think the variables sorted by address is: ISA_END_ADDRESS -> _end -> real_end -> end >+ memory_map_from_high(ISA_END_ADDRESS, real_end); If this is overlap with work done between #ifdef CONFIG_MOVABLE_NODE and #endif? Regards, Wanpeng LI > > if (real_end < end) > init_range_memory_mapping(real_end, end); > >+out: >+ /* the ISA range is always mapped regardless of memory holes */ >+ init_memory_mapping(0, ISA_END_ADDRESS); >+ > #ifdef CONFIG_X86_64 > if (max_pfn > max_low_pfn) { > /* can we preseve max_low_pfn ?*/ >-- >1.7.1 > >-- >To unsubscribe, send a message with 'unsubscribe linux-mm' in >the body to majordomo@kvack.org. For more info on Linux MM, >see: http://www.linux-mm.org/ . >Don't email: email@kvack.org -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org