From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-132.freemail.mail.aliyun.com (out30-132.freemail.mail.aliyun.com [115.124.30.132]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6799A20B22 for ; Mon, 11 Nov 2024 10:01:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.132 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731319314; cv=none; b=Pd7NKw0wFHhRTnmAJfPcR2eyfxxz6ha6c/Qcv2zTttX9pHERIb4qN1aCuRwXAN5tWImwatyvwP5xUOqAf9feWtACE3FbBdyE450zghpFdVeRN7tVWCz6cMhr15cbf3r5KVOX1WM6ohbgbmG1iAymwH46KV4EeOyXkK/Muovz2Gk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731319314; c=relaxed/simple; bh=SJ+hZNZb9m58g3dzGrbOXQXxyu1Lqs3eU/fb7y+vTYA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=DUe/uXF3dDKu7cxEv2f6FZy2/CqRb0kMY1UamGb9t+4xxdvrszy5b5sc83CCxWisj8XGQUAnH9akxmiGuKvfi7D/flBTolO938jrMwENq5w4TevweAaLvET7qeFSwJOdM4txo1QHJGnaXt56YBzMJ0A42x5hbd+jgrJOGlGb/3s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=JsWFVmfA; arc=none smtp.client-ip=115.124.30.132 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="JsWFVmfA" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1731319303; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=jRfVA9sgf9WkBHQBixhuiejOzqDiOEflWv7+AjLswzE=; b=JsWFVmfA22YIknJlhtixnP5dYTD3dbEokz7OmcPhatHjKrft3PIcw5nuVZXWJg4Hqy4FYMJ767K3fGcvIZppLmp6qvhL9V5K5Sh8cqIIZRY6906mefxhXUuGjALQTXEsLfm5JjKoI2psLr7mRpbsyhkedKmWRWc2CeRYVv1rh/A= Received: from 30.221.130.244(mailfrom:hsiangkao@linux.alibaba.com fp:SMTPD_---0WJ9OMGm_1731319301 cluster:ay36) by smtp.aliyun-inc.com; Mon, 11 Nov 2024 18:01:42 +0800 Message-ID: Date: Mon, 11 Nov 2024 18:01:41 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] erofs: free pclusters if no cached folio attached To: Chunhai Guo , xiang@kernel.org Cc: chao@kernel.org, huyue2@coolpad.com, jefflexu@linux.alibaba.com, dhavale@google.com, linux-erofs@lists.ozlabs.org, linux-kernel@vger.kernel.org References: <20241111082536.441004-1-guochunhai@vivo.com> From: Gao Xiang In-Reply-To: <20241111082536.441004-1-guochunhai@vivo.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi Chunhai, On 2024/11/11 16:25, Chunhai Guo wrote: > Once a pcluster is fully decompressed and there are no attached cached > folios, its corresponding `struct z_erofs_pcluster` will be freed. This > will significantly reduce the frequency of calls to erofs_shrink_scan() > and the memory allocated for `struct z_erofs_pcluster`. > > The tables below show approximately a 96% reduction in the calls to > erofs_shrink_scan() and in the memory allocated for `struct > z_erofs_pcluster` after applying this patch. The results were obtained > by performing a test to copy a 4.1GB partition on ARM64 Android devices > running the 6.6 kernel with an 8-core CPU and 12GB of memory. > > 1. The reduction in calls to erofs_shrink_scan(): > +-----------------+-----------+----------+---------+ > | | w/o patch | w/ patch | diff | > +-----------------+-----------+----------+---------+ > | Average (times) | 11390 | 390 | -96.57% | > +-----------------+-----------+----------+---------+ > > 2. The reduction in memory released by erofs_shrink_scan(): > +-----------------+-----------+----------+---------+ > | | w/o patch | w/ patch | diff | > +-----------------+-----------+----------+---------+ > | Average (Byte) | 133612656 | 4434552 | -96.68% | > +-----------------+-----------+----------+---------+ > > Signed-off-by: Chunhai Guo > --- > v1 -> v2: > - rename erofs_prepare_to_release_pcluster() to __erofs_try_to_release_pcluster() > - use trylock in z_erofs_put_pcluster() instead of erofs_try_to_release_pcluster() > > v1: https://lore.kernel.org/linux-erofs/588351c0-93f9-4a04-a923-15aae8b71d49@linux.alibaba.com/ > change since v1: > - rebase this patch on "sunset z_erofs_workgroup` series > - remove check on pcl->partial and get rid of `be->try_free` > - update test results base on 6.6 kernel > --- > fs/erofs/zdata.c | 56 ++++++++++++++++++++++++++++++++---------------- > 1 file changed, 38 insertions(+), 18 deletions(-) > > diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c > index 6b73a2307460..c1cb08d536c0 100644 > --- a/fs/erofs/zdata.c > +++ b/fs/erofs/zdata.c > @@ -885,14 +885,11 @@ static void z_erofs_rcu_callback(struct rcu_head *head) > struct z_erofs_pcluster, rcu)); > } > > -static bool erofs_try_to_release_pcluster(struct erofs_sb_info *sbi, > +static bool __erofs_try_to_release_pcluster(struct erofs_sb_info *sbi, > struct z_erofs_pcluster *pcl) > { > - int free = false; > - > - spin_lock(&pcl->lockref.lock); > if (pcl->lockref.count) > - goto out; > + return false; > > /* > * Note that all cached folios should be detached before deleted from > @@ -900,7 +897,7 @@ static bool erofs_try_to_release_pcluster(struct erofs_sb_info *sbi, > * orphan old pcluster when the new one is available in the tree. > */ > if (erofs_try_to_free_all_cached_folios(sbi, pcl)) > - goto out; > + return false; > > /* > * It's impossible to fail after the pcluster is freezed, but in order > @@ -909,8 +906,16 @@ static bool erofs_try_to_release_pcluster(struct erofs_sb_info *sbi, > DBG_BUGON(__xa_erase(&sbi->managed_pslots, pcl->index) != pcl); > > lockref_mark_dead(&pcl->lockref); > - free = true; > -out: > + return true; > +} > + > +static bool erofs_try_to_release_pcluster(struct erofs_sb_info *sbi, > + struct z_erofs_pcluster *pcl) > +{ > + bool free = false; Just few nits. bool free; ? > + > + spin_lock(&pcl->lockref.lock); > + free = __erofs_try_to_release_pcluster(sbi, pcl); > spin_unlock(&pcl->lockref.lock); > if (free) { > atomic_long_dec(&erofs_global_shrink_cnt); > @@ -942,16 +947,26 @@ unsigned long z_erofs_shrink_scan(struct erofs_sb_info *sbi, > return freed; > } > > -static void z_erofs_put_pcluster(struct z_erofs_pcluster *pcl) > +static void z_erofs_put_pcluster(struct erofs_sb_info *sbi, > + struct z_erofs_pcluster *pcl, bool try_free) > { > + bool free = false; > + > if (lockref_put_or_lock(&pcl->lockref)) > return; > > DBG_BUGON(__lockref_is_dead(&pcl->lockref)); > - if (pcl->lockref.count == 1) > - atomic_long_inc(&erofs_global_shrink_cnt); > - --pcl->lockref.count; > + if (--pcl->lockref.count == 0) { > + if (try_free && xa_trylock(&sbi->managed_pslots)) { > + free = __erofs_try_to_release_pcluster(sbi, pcl); > + xa_unlock(&sbi->managed_pslots); > + } > + if (!free) atomic_long_add(!free, &erofs_global_shrink_cnt); ? > + atomic_long_inc(&erofs_global_shrink_cnt); > + } > spin_unlock(&pcl->lockref.lock); > + if (free) > + call_rcu(&pcl->rcu, z_erofs_rcu_callback); > } > > static void z_erofs_pcluster_end(struct z_erofs_decompress_frontend *fe) > @@ -972,7 +987,7 @@ static void z_erofs_pcluster_end(struct z_erofs_decompress_frontend *fe) > * any longer if the pcluster isn't hosted by ourselves. > */ > if (fe->mode < Z_EROFS_PCLUSTER_FOLLOWED_NOINPLACE) > - z_erofs_put_pcluster(pcl); > + z_erofs_put_pcluster(EROFS_I_SB(fe->inode), pcl, false); > > fe->pcl = NULL; > } > @@ -1274,6 +1289,7 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be, > int i, j, jtop, err2; > struct page *page; > bool overlapped; > + bool try_free = true; > > mutex_lock(&pcl->lock); > be->nr_pages = PAGE_ALIGN(pcl->length + pcl->pageofs_out) >> PAGE_SHIFT; > @@ -1332,8 +1348,10 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be, > for (i = 0; i < pclusterpages; ++i) { > page = be->compressed_pages[i]; > if (!page || > - erofs_folio_is_managed(sbi, page_folio(page))) > + erofs_folio_is_managed(sbi, page_folio(page))) { > + try_free = false; > continue; > + } > (void)z_erofs_put_shortlivedpage(be->pagepool, page); > WRITE_ONCE(pcl->compressed_bvecs[i].page, NULL); > } > @@ -1379,6 +1397,12 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be, > /* pcluster lock MUST be taken before the following line */ > WRITE_ONCE(pcl->next, Z_EROFS_PCLUSTER_NIL); > mutex_unlock(&pcl->lock); > + > + if (z_erofs_is_inline_pcluster(pcl)) > + z_erofs_free_pcluster(pcl); > + else > + z_erofs_put_pcluster(sbi, pcl, try_free); > + unnecessary blank line. Thanks, Gao Xiang > return err; > }