| Message ID | 20230529144022.42927-1-wangkefeng.wang@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [-next] mm: page_alloc: simplify has_managed_dma() | expand |
On Mon, May 29, 2023 at 10:40:22PM +0800, Kefeng Wang wrote: > The ZONE_DMA should only exists on Node 0, only check NODE_DATA(0) > is enough, so simplify has_managed_dma() and make it inline. That's true on x86, but is it true on all architectures?
On 2023/5/29 22:26, Matthew Wilcox wrote: > On Mon, May 29, 2023 at 10:40:22PM +0800, Kefeng Wang wrote: >> The ZONE_DMA should only exists on Node 0, only check NODE_DATA(0) >> is enough, so simplify has_managed_dma() and make it inline. > > That's true on x86, but is it true on all architectures? There is no document about numa node info for the DMA_ZONE, + Mike I used 'git grep -w ZONE_DMA arch/' 1) the following archs without NUMA support, so it's true for them, arch/alpha/mm/init.c: max_zone_pfn[ZONE_DMA] = dma_pfn; arch/arm/mm/init.c: max_zone_pfn[ZONE_DMA] = min(arm_dma_pfn_limit, max_low); arch/m68k/mm/init.c: max_zone_pfn[ZONE_DMA] = end_mem >> PAGE_SHIFT; arch/m68k/mm/mcfmmu.c: max_zone_pfn[ZONE_DMA] = PFN_DOWN(_ramend); arch/m68k/mm/motorola.c: max_zone_pfn[ZONE_DMA] = memblock_end_of_DRAM(); arch/m68k/mm/sun3mmu.c: max_zone_pfn[ZONE_DMA] = ((unsigned long)high_memory) >> PAGE_SHIFT; arch/microblaze/mm/init.c: zones_size[ZONE_DMA] = max_low_pfn; arch/microblaze/mm/init.c: zones_size[ZONE_DMA] = max_pfn; 2) Simple check following archs, it seems that it is yes to them too. arch/mips/mm/init.c: max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN; arch/powerpc/mm/mem.c: max_zone_pfns[ZONE_DMA] = min(max_low_pfn, arch/s390/mm/init.c: max_zone_pfns[ZONE_DMA] = PFN_DOWN(MAX_DMA_ADDRESS); arch/sparc/mm/srmmu.c: max_zone_pfn[ZONE_DMA] = max_low_pfn; arch/x86/mm/init.c: max_zone_pfns[ZONE_DMA] = min(MAX_DMA_PFN, max_low_pfn); arch/arm64/mm/init.c: max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit); arch/loongarch/mm/init.c: max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
On 05/30/23 at 10:10am, Kefeng Wang wrote: > > > On 2023/5/29 22:26, Matthew Wilcox wrote: > > On Mon, May 29, 2023 at 10:40:22PM +0800, Kefeng Wang wrote: > > > The ZONE_DMA should only exists on Node 0, only check NODE_DATA(0) > > > is enough, so simplify has_managed_dma() and make it inline. > > > > That's true on x86, but is it true on all architectures? > > There is no document about numa node info for the DMA_ZONE, + Mike > > I used 'git grep -w ZONE_DMA arch/' willy is right. max_zone_pfn can only limit the range of zone, but can't decide which zone is put on which node. The memory layout is decided by firmware. I searched commit log to get below commit which can give a good example. commit c1d0da83358a2316d9be7f229f26126dbaa07468 Author: Laurent Dufour <ldufour@linux.ibm.com> Date: Fri Sep 25 21:19:28 2020 -0700 mm: replace memmap_context by meminit_context Patch series "mm: fix memory to node bad links in sysfs", v3. Sometimes, firmware may expose interleaved memory layout like this: Early memory node ranges node 1: [mem 0x0000000000000000-0x000000011fffffff] node 2: [mem 0x0000000120000000-0x000000014fffffff] node 1: [mem 0x0000000150000000-0x00000001ffffffff] node 0: [mem 0x0000000200000000-0x000000048fffffff] node 2: [mem 0x0000000490000000-0x00000007ffffffff] > > 1) the following archs without NUMA support, so it's true for them, > > arch/alpha/mm/init.c: max_zone_pfn[ZONE_DMA] = dma_pfn; > arch/arm/mm/init.c: max_zone_pfn[ZONE_DMA] = min(arm_dma_pfn_limit, > max_low); > arch/m68k/mm/init.c: max_zone_pfn[ZONE_DMA] = end_mem >> PAGE_SHIFT; > arch/m68k/mm/mcfmmu.c: max_zone_pfn[ZONE_DMA] = PFN_DOWN(_ramend); > arch/m68k/mm/motorola.c: max_zone_pfn[ZONE_DMA] = memblock_end_of_DRAM(); > arch/m68k/mm/sun3mmu.c: max_zone_pfn[ZONE_DMA] = ((unsigned > long)high_memory) >> PAGE_SHIFT; > arch/microblaze/mm/init.c: zones_size[ZONE_DMA] = max_low_pfn; > arch/microblaze/mm/init.c: zones_size[ZONE_DMA] = max_pfn; > > > 2) Simple check following archs, it seems that it is yes to them too. > > arch/mips/mm/init.c: max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN; > arch/powerpc/mm/mem.c: max_zone_pfns[ZONE_DMA] = min(max_low_pfn, > arch/s390/mm/init.c: max_zone_pfns[ZONE_DMA] = PFN_DOWN(MAX_DMA_ADDRESS); > arch/sparc/mm/srmmu.c: max_zone_pfn[ZONE_DMA] = max_low_pfn; > arch/x86/mm/init.c: max_zone_pfns[ZONE_DMA] = min(MAX_DMA_PFN, > max_low_pfn); > arch/arm64/mm/init.c: max_zone_pfns[ZONE_DMA] = > PFN_DOWN(arm64_dma_phys_limit); > arch/loongarch/mm/init.c: max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN; >
On 2023/5/30 12:18, Baoquan He wrote: > On 05/30/23 at 10:10am, Kefeng Wang wrote: >> >> >> On 2023/5/29 22:26, Matthew Wilcox wrote: >>> On Mon, May 29, 2023 at 10:40:22PM +0800, Kefeng Wang wrote: >>>> The ZONE_DMA should only exists on Node 0, only check NODE_DATA(0) >>>> is enough, so simplify has_managed_dma() and make it inline. >>> >>> That's true on x86, but is it true on all architectures? >> >> There is no document about numa node info for the DMA_ZONE, + Mike >> >> I used 'git grep -w ZONE_DMA arch/' > > willy is right. max_zone_pfn can only limit the range of zone, but > can't decide which zone is put on which node. The memory layout is > decided by firmware. I searched commit log to get below commit which > can give a good example. > > commit c1d0da83358a2316d9be7f229f26126dbaa07468 > Author: Laurent Dufour <ldufour@linux.ibm.com> > Date: Fri Sep 25 21:19:28 2020 -0700 > > mm: replace memmap_context by meminit_context > > Patch series "mm: fix memory to node bad links in sysfs", v3. > > Sometimes, firmware may expose interleaved memory layout like this: > > Early memory node ranges > node 1: [mem 0x0000000000000000-0x000000011fffffff] > node 2: [mem 0x0000000120000000-0x000000014fffffff] > node 1: [mem 0x0000000150000000-0x00000001ffffffff] > node 0: [mem 0x0000000200000000-0x000000048fffffff] > node 2: [mem 0x0000000490000000-0x00000007ffffffff] Oh, it looks strange, but it do occur if firmware report as this way. Thanks Willy and Baoquan, please ignore the patch.
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 5a7ada0413da..48e9fd8eccb4 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1503,16 +1503,6 @@ static inline int is_highmem(struct zone *zone) return is_highmem_idx(zone_idx(zone)); } -#ifdef CONFIG_ZONE_DMA -bool has_managed_dma(void); -#else -static inline bool has_managed_dma(void) -{ - return false; -} -#endif - - #ifndef CONFIG_NUMA extern struct pglist_data contig_page_data; @@ -1527,6 +1517,17 @@ static inline struct pglist_data *NODE_DATA(int nid) #endif /* !CONFIG_NUMA */ +static inline bool has_managed_dma(void) +{ +#ifdef CONFIG_ZONE_DMA + struct zone *zone = NODE_DATA(0)->node_zones + ZONE_DMA; + + if (managed_zone(zone)) + return true; +#endif + return false; +} + extern struct pglist_data *first_online_pgdat(void); extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat); extern struct zone *next_zone(struct zone *zone); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index e671c747892f..e847b39939b8 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6613,18 +6613,3 @@ bool put_page_back_buddy(struct page *page) return ret; } #endif - -#ifdef CONFIG_ZONE_DMA -bool has_managed_dma(void) -{ - struct pglist_data *pgdat; - - for_each_online_pgdat(pgdat) { - struct zone *zone = &pgdat->node_zones[ZONE_DMA]; - - if (managed_zone(zone)) - return true; - } - return false; -} -#endif /* CONFIG_ZONE_DMA */
The ZONE_DMA should only exists on Node 0, only check NODE_DATA(0) is enough, so simplify has_managed_dma() and make it inline. Cc: Baoquan He <bhe@redhat.com> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> --- include/linux/mmzone.h | 21 +++++++++++---------- mm/page_alloc.c | 15 --------------- 2 files changed, 11 insertions(+), 25 deletions(-)