[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v4 2/6] xen: do not merge reserved pages in free_heap_pages()
The code in free_heap_pages() will try to merge pages with the successor/predecessor if pages are suitably aligned. So if the pages reserved are right next to the pages given to the heap allocator, free_heap_pages() will merge them, and give the reserved pages to heap allocator accidently as a result. So in order to avoid the above scenario, this commit updates free_heap_pages() to check whether the predecessor and/or successor has PGC_reserved set, when trying to merge the about-to-be-freed chunk with the predecessor and/or successor. Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx> Suggested-by: Julien Grall <jgrall@xxxxxxxxxx> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> --- v4 changes: - commit message refinement --- v3 changes: - no changes --- v2 changes: - new commit --- xen/common/page_alloc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c index 5e569a48a2..290526adaf 100644 --- a/xen/common/page_alloc.c +++ b/xen/common/page_alloc.c @@ -1483,6 +1483,7 @@ static void free_heap_pages( /* Merge with predecessor block? */ if ( !mfn_valid(page_to_mfn(predecessor)) || !page_state_is(predecessor, free) || + (predecessor->count_info & PGC_reserved) || (PFN_ORDER(predecessor) != order) || (phys_to_nid(page_to_maddr(predecessor)) != node) ) break; @@ -1506,6 +1507,7 @@ static void free_heap_pages( /* Merge with successor block? */ if ( !mfn_valid(page_to_mfn(successor)) || !page_state_is(successor, free) || + (successor->count_info & PGC_reserved) || (PFN_ORDER(successor) != order) || (phys_to_nid(page_to_maddr(successor)) != node) ) break; -- 2.25.1
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