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[90.233.217.52]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-54d6dfa2e7csm2210e87.190.2025.04.17.09.18.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Apr 2025 09:18:59 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Thu, 17 Apr 2025 18:18:57 +0200 To: Baoquan He Cc: Uladzislau Rezki , linux-mm@kvack.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/5] mm/vmalloc.c: optimize code in decay_va_pool_node() a little bit Message-ID: References: <20250415023952.27850-1-bhe@redhat.com> <20250415023952.27850-4-bhe@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Apr 17, 2025 at 10:51:44AM +0800, Baoquan He wrote: > On 04/16/25 at 03:50pm, Uladzislau Rezki wrote: > > On Tue, Apr 15, 2025 at 10:39:50AM +0800, Baoquan He wrote: > > > 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. > > > > > > Signed-off-by: Baoquan He > > > --- > > > mm/vmalloc.c | 23 +++++++++++------------ > > > 1 file changed, 11 insertions(+), 12 deletions(-) > > > > > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > > > index 488d69b56765..bf735c890878 100644 > > > --- a/mm/vmalloc.c > > > +++ b/mm/vmalloc.c > > > @@ -2150,7 +2150,7 @@ 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, len; > > > int i; > > > > > > for (i = 0; i < MAX_VA_SIZE_PAGES; i++) { > > > @@ -2164,22 +2164,20 @@ 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); > > > + 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; > > > + 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; > > > - } > > > + n_decay--; > > > } > > > > > > /* > > > @@ -2188,9 +2186,10 @@ 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); > > > + vn->pool[i].len = len; > > > spin_unlock(&vn->pool_lock); > > > } > > > } > > > -- > > > 2.41.0 > > > > > Which Linux version this patch is based on? I can not apply it. > > I can apply them on the latest mainline kernel, next/master and > mm-new branch of akpm/mm.git. I checked just now. > Sounds good. -- Uladzislau Rezki