[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH] xen/page_alloc: Don't hold the heap_lock when clearing PGC_need_scrub
From: Julien Grall <jgrall@xxxxxxxxxx> Currently, the heap_lock is held when clearing PGC_need_scrub in alloc_heap_pages(). However, this is unnecessary because the only caller (mark_page_offline()) that can concurrently modify the count_info is using cmpxchg() in a loop. Therefore, rework the code to avoid holding the heap_lock and use test_and_clear_bit() instead. Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx> --- xen/common/page_alloc.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c index 68e47d963842..70146a00ec8b 100644 --- a/xen/common/page_alloc.c +++ b/xen/common/page_alloc.c @@ -1038,16 +1038,12 @@ static struct page_info *alloc_heap_pages( { for ( i = 0; i < (1U << order); i++ ) { - if ( test_bit(_PGC_need_scrub, &pg[i].count_info) ) + if ( test_and_clear_bit(_PGC_need_scrub, &pg[i].count_info) ) { if ( !(memflags & MEMF_no_scrub) ) scrub_one_page(&pg[i]); dirty_cnt++; - - spin_lock(&heap_lock); - pg[i].count_info &= ~PGC_need_scrub; - spin_unlock(&heap_lock); } else if ( !(memflags & MEMF_no_scrub) ) check_one_page(&pg[i]); -- 2.17.1
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