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b=D0c1jH74lsUlDSMa3ELkDTKijMkqveJm6LsL81Sx0ma+ccTrHUXrcHMegPgew044d iHcoNpWTVW9Tkb+KjBc+wjuiql254mwWnFH+IEE6JTyzWP69iALX4w2WXu9arsnVTX KLPiskp39LfseoJhfHX/TJ3W859qKlr3qWYamIyVEjiKoUBrmM0vO3DjzURvmv4lC/ darEIMfVk+HuS/rcSTqIB05xbymnlelCexgKHmoWGf3MdT5O3cnggk6ZVmRONOtf7q CCF9JLf4pC40PBjg7pRxuCL2lYk5TdfyaluGh4yRCT3oEwBfvalvFyyEdDZE2VBrWK 7ornIKdTuapAw== Date: Tue, 26 Mar 2024 08:44:11 +0200 From: Mike Rapoport To: Baoquan He Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, akpm@linux-foundation.org Subject: Re: [PATCH v2 1/6] x86: remove unneeded memblock_find_dma_reserve() Message-ID: References: <20240325145646.1044760-1-bhe@redhat.com> <20240325145646.1044760-2-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240325145646.1044760-2-bhe@redhat.com> X-Stat-Signature: j15q1g9qo7au4sdxaqoghy69sz5z4ek5 X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: EC58C12001A X-Rspam-User: X-HE-Tag: 1711435497-750448 X-HE-Meta: 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 VGmXaWBo 21a+ZoGvj1tb50FAAJV1BZdgGNdisNyZ/IQ3gJ6iJ8ij5KP2sH2JITF+nUevjx1NgpNpLj61QRZVOyZYM7VjZugx2AIr7GqEtbBj9rIdAviRg7LQGHH8RlXFpi09O+3pXUxt64ZP2zWqM9Dp0Fm7bYkBoDo7AOawDiQ6O4p8AAppXapS9FPnH52pTSkOzJlsYYDjA8kzYXUtLA6lPntvW6F9nFSDqiF0IAgL27YJINRaVzDgpM99xlRI0xjLEHjRoPkMOhrZknph4cJfw5Xeh4cTmF+iF5kMsB//aqRLLZvKxjWNTGdX0nmgx26hXL32XjFRp 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: List-Subscribe: List-Unsubscribe: On Mon, Mar 25, 2024 at 10:56:41PM +0800, Baoquan He wrote: > Variable dma_reserve and its usage was introduced in commit 0e0b864e069c > ("[PATCH] Account for memmap and optionally the kernel image as holes"). > Its original purpose was to accounting for the reserved pages in DMA > zone to make DMA zone's watermarks calculation more accurate on x86. > > However, currently there's zone->managed_pages to account for all > available pages for buddy, zone->present_pages to account for all > present physical pages in zone. What is more important, on x86, > calculating and setting the zone->managed_pages is a temporary move, > all zone's managed_pages will be zeroed out and reset to the actual > value according to how many pages are added to buddy allocator in > mem_init(). Before mem_init(), no buddy alloction is requested. And > zone's pcp and watermark setting are all done after mem_init(). So, > no need to worry about the DMA zone's setting accuracy during > free_area_init(). > > Hence, remove memblock_find_dma_reserve() to stop calculating and > setting dma_reserve. > > Signed-off-by: Baoquan He Reviewed-by: Mike Rapoport (IBM) > --- > arch/x86/include/asm/pgtable.h | 1 - > arch/x86/kernel/setup.c | 2 -- > arch/x86/mm/init.c | 47 ---------------------------------- > 3 files changed, 50 deletions(-) > > diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h > index 315535ffb258..cefc7a84f7a4 100644 > --- a/arch/x86/include/asm/pgtable.h > +++ b/arch/x86/include/asm/pgtable.h > @@ -1200,7 +1200,6 @@ static inline int pgd_none(pgd_t pgd) > extern int direct_gbpages; > void init_mem_mapping(void); > void early_alloc_pgt_buf(void); > -extern void memblock_find_dma_reserve(void); > void __init poking_init(void); > unsigned long init_memory_mapping(unsigned long start, > unsigned long end, pgprot_t prot); > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c > index ef206500ed6f..74873bd04ad1 100644 > --- a/arch/x86/kernel/setup.c > +++ b/arch/x86/kernel/setup.c > @@ -1106,8 +1106,6 @@ void __init setup_arch(char **cmdline_p) > */ > arch_reserve_crashkernel(); > > - memblock_find_dma_reserve(); > - > if (!early_xdbc_setup_hardware()) > early_xdbc_register_console(); > > diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c > index 679893ea5e68..615f0bf4bda6 100644 > --- a/arch/x86/mm/init.c > +++ b/arch/x86/mm/init.c > @@ -990,53 +990,6 @@ void __init free_initrd_mem(unsigned long start, unsigned long end) > } > #endif > > -/* > - * Calculate the precise size of the DMA zone (first 16 MB of RAM), > - * and pass it to the MM layer - to help it set zone watermarks more > - * accurately. > - * > - * Done on 64-bit systems only for the time being, although 32-bit systems > - * might benefit from this as well. > - */ > -void __init memblock_find_dma_reserve(void) > -{ > -#ifdef CONFIG_X86_64 > - u64 nr_pages = 0, nr_free_pages = 0; > - unsigned long start_pfn, end_pfn; > - phys_addr_t start_addr, end_addr; > - int i; > - u64 u; > - > - /* > - * Iterate over all memory ranges (free and reserved ones alike), > - * to calculate the total number of pages in the first 16 MB of RAM: > - */ > - nr_pages = 0; > - for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) { > - start_pfn = min(start_pfn, MAX_DMA_PFN); > - end_pfn = min(end_pfn, MAX_DMA_PFN); > - > - nr_pages += end_pfn - start_pfn; > - } > - > - /* > - * Iterate over free memory ranges to calculate the number of free > - * pages in the DMA zone, while not counting potential partial > - * pages at the beginning or the end of the range: > - */ > - nr_free_pages = 0; > - for_each_free_mem_range(u, NUMA_NO_NODE, MEMBLOCK_NONE, &start_addr, &end_addr, NULL) { > - start_pfn = min_t(unsigned long, PFN_UP(start_addr), MAX_DMA_PFN); > - end_pfn = min_t(unsigned long, PFN_DOWN(end_addr), MAX_DMA_PFN); > - > - if (start_pfn < end_pfn) > - nr_free_pages += end_pfn - start_pfn; > - } > - > - set_dma_reserve(nr_pages - nr_free_pages); > -#endif > -} > - > void __init zone_sizes_init(void) > { > unsigned long max_zone_pfns[MAX_NR_ZONES]; > -- > 2.41.0 > -- Sincerely yours, Mike.