From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id 54B84708AB; Mon, 7 Jun 2021 17:35:56 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 7BFEF12F05; Mon, 7 Jun 2021 17:35:55 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id B21D012D5A; Mon, 7 Jun 2021 17:35:46 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 8132B46169; Mon, 7 Jun 2021 17:35:46 +0200 (CEST) From: Stefan Reiter To: pve-devel@lists.proxmox.com, pbs-devel@lists.proxmox.com Date: Mon, 7 Jun 2021 17:35:31 +0200 Message-Id: <20210607153532.2522267-9-s.reiter@proxmox.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210607153532.2522267-1-s.reiter@proxmox.com> References: <20210607153532.2522267-1-s.reiter@proxmox.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL 0.880 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Subject: [pbs-devel] [PATCH v2 proxmox-backup-qemu 8/9] add shared_cache module X-BeenThere: pbs-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox Backup Server development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 07 Jun 2021 15:35:56 -0000 Provides a shared AsyncLruCache of 256MB (w/ 4MB chunks) that can be used by multiple readers at the same time. It is dropped once no more readers exist, so the memory gets freed if all QEMU block/pbs instances disappear. Signed-off-by: Stefan Reiter --- v2: * adapt to dropping ChunkCache type alias from proxmox-backup * I re-add it here locally only because otherwise the type of SHARED_CACHE ends in 7 '>'s src/lib.rs | 7 ++++++- src/shared_cache.rs | 37 +++++++++++++++++++++++++++++++++++++ 2 files changed, 43 insertions(+), 1 deletion(-) create mode 100644 src/shared_cache.rs diff --git a/src/lib.rs b/src/lib.rs index 05d7b58..aa167f7 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -25,6 +25,7 @@ mod restore; use restore::*; mod tools; +mod shared_cache; pub const PROXMOX_BACKUP_DEFAULT_CHUNK_SIZE: u64 = 1024*1024*4; @@ -804,7 +805,11 @@ pub extern "C" fn proxmox_restore_connect_async( pub extern "C" fn proxmox_restore_disconnect(handle: *mut ProxmoxRestoreHandle) { let restore_task = handle as * mut Arc; - unsafe { Box::from_raw(restore_task) }; //drop(restore_task) + let restore_task = unsafe { Box::from_raw(restore_task) }; + drop(restore_task); + + // after dropping, cache may be unused (if no other handles open) + shared_cache::shared_chunk_cache_cleanup(); } /// Restore an image (sync) diff --git a/src/shared_cache.rs b/src/shared_cache.rs new file mode 100644 index 0000000..32ac430 --- /dev/null +++ b/src/shared_cache.rs @@ -0,0 +1,37 @@ +use once_cell::sync::OnceCell; +use proxmox_backup::tools::async_lru_cache::AsyncLruCache; +use std::sync::{Arc, Mutex}; + +type ChunkCache = AsyncLruCache<[u8; 32], Arc>>; + +const SHARED_CACHE_CAPACITY: usize = 64; // 256 MB +static SHARED_CACHE: OnceCell>>> = OnceCell::new(); + +pub fn get_shared_chunk_cache() -> Arc { + let mut guard = SHARED_CACHE + .get_or_init(|| Mutex::new(None)) + .lock() + .unwrap(); + match &*guard { + Some(cache) => Arc::clone(cache), + None => { + let cache = Arc::new(AsyncLruCache::new(SHARED_CACHE_CAPACITY)); + *guard = Some(Arc::clone(&cache)); + cache + } + } +} + +pub fn shared_chunk_cache_cleanup() { + let mut guard = SHARED_CACHE + .get_or_init(|| Mutex::new(None)) + .lock() + .unwrap(); + if let Some(arc) = guard.as_ref() { + let refcount = Arc::strong_count(arc); + if refcount == 1 { + // no one else is using the cache anymore, drop it + let _drop = guard.take(); + } + } +} -- 2.30.2