From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 92D843AFD0D for ; Thu, 27 Aug 2026 12:25:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787833553; cv=none; b=O6rM2ktU+5J7uUpSC+lLPQuTkvCbdiyq+J6AQ10hlLSxrNAA5edXQn7L54ev/Ihb8zeTDmhbCd1inr8OgAjNKvp7Cp2n/jdj9hH+aKaVUJu43PwBZ7p2kpWaefl0mbVqxvhXYk/n5FnlIF0XL5KrO5doK/ULW0saspbcl0MbCg4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787833553; c=relaxed/simple; bh=0LBaZnnh4JyGOEOuESU9905xWAADSobr88/ckgAFtyE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BXPNwdEAjm2Z7Ks/8e6OE3k15CNUsF9RQVtcD/LaSrBVqQOHgRlOvR7imlMsO/N7YpSP6h6jliB0adEnFwjWXvDDxWKXnWLlEMdsD0UBOmajfMQGD6IQwSx+UwFcUBDByyesyJLqZFn8dW2L/FyclMaT6QzEJqboa6o0LrJVTHY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mm8++Yy+; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mm8++Yy+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75A241F00A3D; Thu, 27 Aug 2026 12:25:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787833552; bh=1rDvh5omJ1P80S+w+/I4psAk/R31yuaCneN5y8ReDlg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mm8++Yy+4h/8iCyf2VGfULMfq9r3Asavz3ndiYvkc3uckKxTSGMDdFCDKT4Wy/7jE 7ibN8Xwe450Y6TD/PqFRzsxd1vw4Y5NrdUB8ncAcifnICWt1UUS7HFLfG0brr26KXq oOyLoBlbJnsVasfDhUpZr35lAJexxNgrV0X+OjJUqt89VZIdrkfelxeiUD+4BFRKSz YKCTd7k6BpM6ZDQ1wtLbCJ34Mq+GKvc9IK6FtP5OgZFdtzFMCE/rQfWs+hXF4Nmk9E SRMM6fIAniifHLAJzEGjtW16T/MtzS5+andQ+g3sDo2CzrRjIx/8ZJsMiF6sIMf1tO Qh9yHuShZ3mRA== From: Chao Yu To: jaegeuk@kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu Subject: [PATCH v4 03/12] f2fs: cache: introduce shrinker Date: Thu, 27 Aug 2026 20:25:31 +0800 Message-ID: <20260827122541.19967-4-chao@kernel.org> X-Mailer: git-send-email 2.55.0.887.g758fc8c411-goog In-Reply-To: <20260827122541.19967-1-chao@kernel.org> References: <20260827122541.19967-1-chao@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Chao Yu This patch integrates the metadata cache into the F2FS memory shrinker subsystem to reclaim clean, unreferenced cached blocks under memory pressure. It implements f2fs_shrink_cache() using a 3-phase cache reclamin method: 1. isolate clean entries from lru list 2. truncate from radix tree under lock 3. splice un-reclaimed entries back And hooks the new interface into f2fs_shrink_count() and f2fs_shrink_scan(). Signed-off-by: Chao Yu --- fs/f2fs/cache.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++ fs/f2fs/cache.h | 3 ++ fs/f2fs/shrinker.c | 12 +++++++ 3 files changed, 95 insertions(+) diff --git a/fs/f2fs/cache.c b/fs/f2fs/cache.c index a1a73fa84320..0cb8622ef580 100644 --- a/fs/f2fs/cache.c +++ b/fs/f2fs/cache.c @@ -560,3 +560,83 @@ void f2fs_destroy_cache(struct f2fs_cached_block_list *cache) f2fs_put_cache(entry, true); goto next; } + +static unsigned long f2fs_do_shrink_cache(struct f2fs_cached_block_list *cache, + unsigned long nr_to_scan) +{ + struct f2fs_cached_block *entry, *next; + LIST_HEAD(dispose_list); + LIST_HEAD(keep_list); + unsigned long freed = 0; + + /* Phase 1: Isolate candidate entries from LRU list into dispose_list */ + spin_lock(&cache->list_lock); + list_for_each_entry_safe(entry, next, &cache->lru_list, list) { + if (nr_to_scan-- == 0) + break; + + if (f2fs_cache_test_dirty(entry) || + f2fs_cache_test_writeback(entry) || + f2fs_cache_test_locked(entry)) + continue; + + if (f2fs_cache_refcount(entry) != 1) + continue; + + list_move_tail(&entry->list, &dispose_list); + } + spin_unlock(&cache->list_lock); + + /* Phase 2: Process isolated candidates one by one */ + while (1) { + spin_lock(&cache->list_lock); + entry = list_first_entry_or_null(&dispose_list, + struct f2fs_cached_block, list); + if (!entry) { + spin_unlock(&cache->list_lock); + break; + } + f2fs_cache_get(entry); + list_move_tail(&entry->list, &keep_list); + spin_unlock(&cache->list_lock); + + if (!f2fs_trylock_cache(entry)) { + f2fs_put_cache(entry, false); + continue; + } + + /* the entry has been truncated */ + if (!entry->cache) { + f2fs_put_cache(entry, true); + continue; + } + /* + * at least there are shrinker, radix tree and another user + * has referenced the entry. + */ + if (f2fs_cache_refcount(entry) >= 3) { + f2fs_put_cache(entry, true); + continue; + } + + f2fs_do_truncate_cache(entry, false); + + if (f2fs_put_cache(entry, true)) + freed++; + } + + /* Phase 3: Splice un-reclaimed entries back onto cache->lru_list */ + if (!list_empty(&keep_list)) { + spin_lock(&cache->list_lock); + list_splice_tail(&keep_list, &cache->lru_list); + spin_unlock(&cache->list_lock); + } + + return freed; +} + +unsigned long f2fs_shrink_cache(struct f2fs_sb_info *sbi, + unsigned long nr_to_scan) +{ + return f2fs_do_shrink_cache(META_CACHE(sbi), nr_to_scan); +} diff --git a/fs/f2fs/cache.h b/fs/f2fs/cache.h index cb5a466526fc..5f7e74f0c873 100644 --- a/fs/f2fs/cache.h +++ b/fs/f2fs/cache.h @@ -191,4 +191,7 @@ void f2fs_stop_cache_wb_thread(struct f2fs_sb_info *sbi); #define f2fs_truncate_meta_caches(sbi, start, len) \ f2fs_drop_cache_range(META_CACHE(sbi), start, len, true) +unsigned long f2fs_shrink_cache(struct f2fs_sb_info *sbi, + unsigned long nr_to_scan); + #endif /* _LINUX_F2FS_CACHE_H */ diff --git a/fs/f2fs/shrinker.c b/fs/f2fs/shrinker.c index 4f6bf5926de4..8ef3aa5eb110 100644 --- a/fs/f2fs/shrinker.c +++ b/fs/f2fs/shrinker.c @@ -37,6 +37,11 @@ static unsigned long __count_extent_cache(struct f2fs_sb_info *sbi, atomic_read(&eti->total_ext_node); } +static unsigned long __count_cache(struct f2fs_sb_info *sbi) +{ + return META_CACHE(sbi)->num_entries; +} + unsigned long f2fs_shrink_count(struct shrinker *shrink, struct shrink_control *sc) { @@ -68,6 +73,9 @@ unsigned long f2fs_shrink_count(struct shrinker *shrink, /* count free nids cache entries */ count += __count_free_nids(sbi); + /* count generic cache entries */ + count += __count_cache(sbi); + spin_lock(&f2fs_list_lock); p = p->next; mutex_unlock(&sbi->umount_mutex); @@ -120,6 +128,10 @@ unsigned long f2fs_shrink_scan(struct shrinker *shrink, if (freed < nr) freed += f2fs_try_to_free_nids(sbi, nr - freed); + /* shrink generic cache entries */ + if (freed < nr) + freed += f2fs_shrink_cache(sbi, nr - freed); + spin_lock(&f2fs_list_lock); p = p->next; list_move_tail(&sbi->s_list, &f2fs_list); -- 2.49.0