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mm/cma: provide option to opt out from exposing pages on activation failure

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Patch series "powerpc/fadump: handle CMA activation failure appropriately", v3.

Commit 072355c1cf ("mm/cma: expose all pages to the buddy if
activation of an area fails") started exposing all pages to buddy
allocator on CMA activation failure.  But there can be CMA users that
want to handle the reserved memory differently on CMA allocation
failure.

Provide an option to opt out from exposing pages to buddy for such
cases.

Link: https://lkml.kernel.org/r/20220117075246.36072-1-hbathini@linux.ibm.com
Link: https://lkml.kernel.org/r/20220117075246.36072-2-hbathini@linux.ibm.com
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Cc: Sourabh Jain <sourabhjain@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Hari Bathini 2022-03-22 14:46:14 -07:00 committed by Linus Torvalds
parent 9d84604b84
commit 27d121d0ec
3 changed files with 12 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/cma.h
View File

@ -58,4 +58,6 @@ extern bool cma_pages_valid(struct cma *cma, const struct page *pages, unsigned
extern bool cma_release(struct cma *cma, const struct page *pages, unsigned long count);
extern int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data);
extern void cma_reserve_pages_on_error(struct cma *cma);
#endif

11
mm/cma.c
View File

@ -131,8 +131,10 @@ static void __init cma_activate_area(struct cma *cma)
bitmap_free(cma->bitmap);
out_error:
/* Expose all pages to the buddy, they are useless for CMA. */
for (pfn = base_pfn; pfn < base_pfn + cma->count; pfn++)
free_reserved_page(pfn_to_page(pfn));
if (!cma->reserve_pages_on_error) {
for (pfn = base_pfn; pfn < base_pfn + cma->count; pfn++)
free_reserved_page(pfn_to_page(pfn));
}
totalcma_pages -= cma->count;
cma->count = 0;
pr_err("CMA area %s could not be activated\n", cma->name);
@ -150,6 +152,11 @@ static int __init cma_init_reserved_areas(void)
}
core_initcall(cma_init_reserved_areas);
void __init cma_reserve_pages_on_error(struct cma *cma)
{
cma->reserve_pages_on_error = true;
}
/**
* cma_init_reserved_mem() - create custom contiguous area from reserved memory
* @base: Base address of the reserved area

1
mm/cma.h
View File

@ -30,6 +30,7 @@ struct cma {
/* kobject requires dynamic object */
struct cma_kobject *cma_kobj;
#endif
bool reserve_pages_on_error;
};
extern struct cma cma_areas[MAX_CMA_AREAS];