| Message ID | 1503952829-11065-5-git-send-email-boris.ostrovsky@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Aug 28, 2017 at 04:40:29PM -0400, Boris Ostrovsky wrote: > Once pages are removed from the heap we don't need to hold the heap > lock. It is especially useful to drop it for an unscrubbed buddy since > we will be scrubbing it. > > Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Wei Liu <wei.liu2@citrix.com>
>>> On 28.08.17 at 22:40, <boris.ostrovsky@oracle.com> wrote: > @@ -943,6 +944,8 @@ static struct page_info *alloc_heap_pages( > > check_low_mem_virq(); > > + spin_unlock(&heap_lock); > + > if ( d != NULL ) > d->last_alloc_node = node; I'm not sure about the placement - as long as there's only a single heap lock it certainly also protects the last_alloc_node updates visible in context here. The consumer of this field also holds the heap lock afaict, so at least for the moment it would feel more safe if you moved the unlock past that update. With that feel free to add Reviewed-by: Jan Beulich <jbeulich@suse.com> Jan
diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c index b93dae9..1ec788e 100644 --- a/xen/common/page_alloc.c +++ b/xen/common/page_alloc.c @@ -858,6 +858,7 @@ static struct page_info *alloc_heap_pages( struct page_info *pg; bool need_tlbflush = false; uint32_t tlbflush_timestamp = 0; + unsigned int dirty_cnt = 0; /* Make sure there are enough bits in memflags for nodeID. */ BUILD_BUG_ON((_MEMF_bits - _MEMF_node) < (8 * sizeof(nodeid_t))); @@ -943,6 +944,8 @@ static struct page_info *alloc_heap_pages( check_low_mem_virq(); + spin_unlock(&heap_lock); + if ( d != NULL ) d->last_alloc_node = node; @@ -955,7 +958,7 @@ static struct page_info *alloc_heap_pages( { if ( !(memflags & MEMF_no_scrub) ) scrub_one_page(&pg[i]); - node_need_scrub[node]--; + dirty_cnt++; } pg[i].count_info = PGC_state_inuse; @@ -977,6 +980,8 @@ static struct page_info *alloc_heap_pages( check_one_page(&pg[i]); } + spin_lock(&heap_lock); + node_need_scrub[node] -= dirty_cnt; spin_unlock(&heap_lock); if ( need_tlbflush )
Once pages are removed from the heap we don't need to hold the heap lock. It is especially useful to drop it for an unscrubbed buddy since we will be scrubbing it. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> --- xen/common/page_alloc.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)