From: Baoquan He Date: Fri, 18 Apr 2025 22:36:51 +0000 (+0800) Subject: mm/vmalloc.c: optimize code in decay_va_pool_node() a little bit X-Git-Tag: v6.16-rc1~92^2~135 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4f05024eba021f1885c044c8515b6a2674b652de;p=thirdparty%2Flinux.git mm/vmalloc.c: optimize code in decay_va_pool_node() a little bit When purge lazily freed vmap areas, VA stored in vn->pool[] will also be taken away into free vmap tree partially or completely accordingly, that is done in decay_va_pool_node(). When doing that, for each pool of node, the whole list is detached from the pool for handling. At this time, that pool is empty. It's not necessary to update the pool size each time when one VA is removed and addded into free vmap tree. Here change code to update the pool size when attaching the pool back. Link: https://lkml.kernel.org/r/20250418223653.243436-4-bhe@redhat.com Signed-off-by: Baoquan He Reviewed-by: Uladzislau Rezki (Sony) Cc: Shivank Garg Cc: Vishal Moola (Oracle) Signed-off-by: Andrew Morton --- diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 26d86ab5e59e1..e58c2ed4bcba7 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2149,7 +2149,7 @@ decay_va_pool_node(struct vmap_node *vn, bool full_decay) LIST_HEAD(decay_list); struct rb_root decay_root = RB_ROOT; struct vmap_area *va, *nva; - unsigned long n_decay; + unsigned long n_decay, pool_len; int i; for (i = 0; i < MAX_VA_SIZE_PAGES; i++) { @@ -2163,22 +2163,20 @@ decay_va_pool_node(struct vmap_node *vn, bool full_decay) list_replace_init(&vn->pool[i].head, &tmp_list); spin_unlock(&vn->pool_lock); - if (full_decay) - WRITE_ONCE(vn->pool[i].len, 0); + pool_len = n_decay = vn->pool[i].len; + WRITE_ONCE(vn->pool[i].len, 0); /* Decay a pool by ~25% out of left objects. */ - n_decay = vn->pool[i].len >> 2; + if (!full_decay) + n_decay >>= 2; + pool_len -= n_decay; list_for_each_entry_safe(va, nva, &tmp_list, list) { + if (!n_decay--) + break; + list_del_init(&va->list); merge_or_add_vmap_area(va, &decay_root, &decay_list); - - if (!full_decay) { - WRITE_ONCE(vn->pool[i].len, vn->pool[i].len - 1); - - if (!--n_decay) - break; - } } /* @@ -2187,9 +2185,10 @@ decay_va_pool_node(struct vmap_node *vn, bool full_decay) * can populate the pool therefore a simple list replace * operation takes place here. */ - if (!full_decay && !list_empty(&tmp_list)) { + if (!list_empty(&tmp_list)) { spin_lock(&vn->pool_lock); list_replace_init(&tmp_list, &vn->pool[i].head); + WRITE_ONCE(vn->pool[i].len, pool_len); spin_unlock(&vn->pool_lock); } }