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https://gitee.com/bianbu-linux/linux-6.6
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e16faf2678
Patch series "mm: enforce pageblock_order < MAX_ORDER". Having pageblock_order >= MAX_ORDER seems to be able to happen in corner cases and some parts of the kernel are not prepared for it. For example, Aneesh has shown [1] that such kernels can be compiled on ppc64 with 64k base pages by setting FORCE_MAX_ZONEORDER=8, which will run into a WARN_ON_ONCE(order >= MAX_ORDER) in comapction code right during boot. We can get pageblock_order >= MAX_ORDER when the default hugetlb size is bigger than the maximum allocation granularity of the buddy, in which case we are no longer talking about huge pages but instead gigantic pages. Having pageblock_order >= MAX_ORDER can only make alloc_contig_range() of such gigantic pages more likely to succeed. Reliable use of gigantic pages either requires boot time allcoation or CMA, no need to overcomplicate some places in the kernel to optimize for corner cases that are broken in other areas of the kernel. This patch (of 2): Let's enforce pageblock_order < MAX_ORDER and simplify. Especially patch #1 can be regarded a cleanup before: [PATCH v5 0/6] Use pageblock_order for cma and alloc_contig_range alignment. [2] [1] https://lkml.kernel.org/r/87r189a2ks.fsf@linux.ibm.com [2] https://lkml.kernel.org/r/20220211164135.1803616-1-zi.yan@sent.com Link: https://lkml.kernel.org/r/20220214174132.219303-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Acked-by: Rob Herring <robh@kernel.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Frank Rowand <frowand.list@gmail.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: John Garry via iommu <iommu@lists.linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
62 lines
2 KiB
C
62 lines
2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __CMA_H__
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#define __CMA_H__
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#include <linux/init.h>
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#include <linux/types.h>
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#include <linux/numa.h>
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/*
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* There is always at least global CMA area and a few optional
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* areas configured in kernel .config.
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*/
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#ifdef CONFIG_CMA_AREAS
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#define MAX_CMA_AREAS (1 + CONFIG_CMA_AREAS)
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#else
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#define MAX_CMA_AREAS (0)
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#endif
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#define CMA_MAX_NAME 64
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/*
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* TODO: once the buddy -- especially pageblock merging and alloc_contig_range()
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* -- can deal with only some pageblocks of a higher-order page being
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* MIGRATE_CMA, we can use pageblock_nr_pages.
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*/
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#define CMA_MIN_ALIGNMENT_PAGES max_t(phys_addr_t, MAX_ORDER_NR_PAGES, \
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pageblock_nr_pages)
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#define CMA_MIN_ALIGNMENT_BYTES (PAGE_SIZE * CMA_MIN_ALIGNMENT_PAGES)
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struct cma;
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extern unsigned long totalcma_pages;
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extern phys_addr_t cma_get_base(const struct cma *cma);
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extern unsigned long cma_get_size(const struct cma *cma);
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extern const char *cma_get_name(const struct cma *cma);
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extern int __init cma_declare_contiguous_nid(phys_addr_t base,
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phys_addr_t size, phys_addr_t limit,
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phys_addr_t alignment, unsigned int order_per_bit,
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bool fixed, const char *name, struct cma **res_cma,
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int nid);
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static inline int __init cma_declare_contiguous(phys_addr_t base,
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phys_addr_t size, phys_addr_t limit,
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phys_addr_t alignment, unsigned int order_per_bit,
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bool fixed, const char *name, struct cma **res_cma)
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{
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return cma_declare_contiguous_nid(base, size, limit, alignment,
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order_per_bit, fixed, name, res_cma, NUMA_NO_NODE);
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}
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extern int cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
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unsigned int order_per_bit,
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const char *name,
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struct cma **res_cma);
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extern struct page *cma_alloc(struct cma *cma, unsigned long count, unsigned int align,
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bool no_warn);
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extern bool cma_pages_valid(struct cma *cma, const struct page *pages, unsigned long count);
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extern bool cma_release(struct cma *cma, const struct page *pages, unsigned long count);
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extern int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data);
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#endif
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