From 42b54bfe29e05563b5bd17182d4b8c2dd5cb1dc6 Mon Sep 17 00:00:00 2001 From: Keir Fraser Date: Mon, 11 Aug 2008 12:20:11 +0100 Subject: [PATCH] page scrub: Serialise softirq with a new lock. Avoids holding up acquiring page_scrub_lock in free_domheap_pages(). Signed-off-by: Keir Fraser --- xen/common/page_alloc.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c index b202570a0f..d9e0a2946a 100644 --- a/xen/common/page_alloc.c +++ b/xen/common/page_alloc.c @@ -950,9 +950,10 @@ static void page_scrub_softirq(void) void *p; int i; s_time_t start = NOW(); + static spinlock_t serialise_lock = SPIN_LOCK_UNLOCKED; /* free_heap_pages() does not parallelise well. Serialise this function. */ - if ( !spin_trylock(&page_scrub_lock) ) + if ( !spin_trylock(&serialise_lock) ) { set_timer(&this_cpu(page_scrub_timer), NOW() + MILLISECS(1)); return; @@ -960,10 +961,12 @@ static void page_scrub_softirq(void) /* Aim to do 1ms of work every 10ms. */ do { + spin_lock(&page_scrub_lock); + if ( unlikely((ent = page_scrub_list.next) == &page_scrub_list) ) { spin_unlock(&page_scrub_lock); - return; + goto out; } /* Peel up to 16 pages from the list. */ @@ -979,6 +982,8 @@ static void page_scrub_softirq(void) page_scrub_list.next = ent->next; scrub_pages -= (i+1); + spin_unlock(&page_scrub_lock); + /* Working backwards, scrub each page in turn. */ while ( ent != &page_scrub_list ) { @@ -991,9 +996,10 @@ static void page_scrub_softirq(void) } } while ( (NOW() - start) < MILLISECS(1) ); - spin_unlock(&page_scrub_lock); - set_timer(&this_cpu(page_scrub_timer), NOW() + MILLISECS(10)); + + out: + spin_unlock(&serialise_lock); } static void page_scrub_timer_fn(void *unused) -- 2.30.2