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 4D9ED1CEADB for ; Thu, 6 Aug 2026 12:34:44 +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=1786019685; cv=none; b=WqUENxjSWkTLfTkuTMgMj/XqU1rOoiQOQFPqFWs0yqMrvV6s4zNjIgZN9M+MtEZJBSerWT24DKEqAbOXg973RpGv67lL730OixKfcum4igfhzfJA32LnAaEyVUsFmR2a/k95bD3jw3YGA8XkeS2cH2/8qeaCcymS030GCSba4hQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786019685; c=relaxed/simple; bh=9dbhaAhGXgeJCObTvIE4OXIth8EDfveyVVDbf44qHYw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=LR8SK+liK3e9eiqbeg9Rdx1CE9rRsXwnYgV6gf5pjEmUOIUh1cIt4dLpZjp4n4450mVfrzx45bnZCw8KtxTpFqtdujlA5p3HOysocB/Gin63KVSA5TuizdeKmiZjhBcqVqOTDE56n83zZsT5B9Fo4KX3GxMNj/c+3TPZuzULVEE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iwFMCzv4; 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="iwFMCzv4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D75E91F000E9; Thu, 6 Aug 2026 12:34:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786019683; bh=kRhKcLQ/QHqM650BruJXkY+BhqZvO7Q7Sx3twySEZj8=; h=From:To:Cc:Subject:Date; b=iwFMCzv4Gpphg1uaeglF1XifLQi78ZGNI7DRR9vyg1S1QbAlBj/xE+NVMj8raxFTg rTFJ75K4vtw8A+2RLtdn5pZdKcQx0gja9O+msujVO0+q976qfqld7HyBzLg7s+/cRn nvjO/kNcKH8bbK6K+8e5o0E5lZ24NhtDvUQT60Xx53CXPFAMZqsw8m4LU41U3Ow0U3 pWK5ihdKnzIEDRfkxgjKsHqYZR+5+kk+3kYpwH2jxG78hGWy1LKwvL/nKfkaMIgQ+f Gmh4F0RXNmv/Q3b6FG0r3oZxy7/BA6Bwo37h96PZT+cmZh58mbsHLJTI8Vk+H4Hk/x Dfm8DI7mlNsAg== From: Chao Yu To: jaegeuk@kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu Subject: [PATCH] f2fs: reduce memory footprint of ino management Date: Thu, 6 Aug 2026 20:34:38 +0800 Message-ID: <20260806123438.1516371-1-chao@kernel.org> X-Mailer: git-send-email 2.55.0.571.g244d577d93-goog Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Currently, ino entries for APPEND_INO, UPDATE_INO, TRANS_DIR_INO, and XATTR_DIR_INO allocate a 'struct ino_entry' slab object and attach it to both a list and a radix tree solely for existence checks via f2fs_exist_written_data(). Since these ino types only track binary existence status, we can embed the information directly into radix tree value entries as a bitmap: - The Linux radix tree/XArray supports in-place value entries via xa_mk_value() / xa_to_value(), which tag the least significant bit to store an unallocated integer value of BITS_PER_XA_VALUE bits (BITS_PER_LONG - 1) directly in the slot pointer. - For each inode, (ino / BITS_PER_XA_VALUE) serves as the radix tree slot index, and (ino % BITS_PER_XA_VALUE) is used as the bit offset within the slot's bitmap. For example, when tracking ino = 7: - Before: Allocate a 'struct ino_entry' ({ .ino = 7 }), insert its pointer into the radix tree at index = 7, and link it to im->ino_list. - After: Compute slot_index = 7 / BITS_PER_XA_VALUE (index 0) and bit_offset = 7 % BITS_PER_XA_VALUE (bit 7), then set bit 7 in the value entry via xa_mk_value(bitmap) at index 0, without allocating a slab object or linking to a list. Additionally: - In-place slot updates are performed via radix_tree_replace_slot(), and slots are deleted with radix_tree_delete() once the bitmap is zeroed. - Reorder the ino list enum so ORPHAN_INO and FLUSH_INO (which still require struct ino_entry and list traversal) remain separated, while bitmap-based trees are torn down using xa_destroy(). This eliminates 'struct ino_entry' slab allocations and linked-list tracking for these ino types, significantly reducing memory consumption. Signed-off-by: Chao Yu --- fs/f2fs/checkpoint.c | 79 +++++++++++++++++++++++++++++++++++++++----- fs/f2fs/f2fs.h | 6 +++- 2 files changed, 76 insertions(+), 9 deletions(-) diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c index 4413eccb5ecb..e2b27fa8941f 100644 --- a/fs/f2fs/checkpoint.c +++ b/fs/f2fs/checkpoint.c @@ -777,26 +777,81 @@ static void f2fs_wait_for_inode_record(struct f2fs_sb_info *sbi, int mode) void f2fs_add_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int type) { - /* add new dirty ino entry into list */ - __add_ino_entry(sbi, ino, 0, type); + struct inode_management *im = &sbi->im[type]; + unsigned long index = INO_SLOT_INDEX(ino); + unsigned int ofs = INO_BIT_OFFSET(ino); + void **slot, *entry; + unsigned long bitmap = 0; + int ret; + + ret = radix_tree_preload(GFP_NOFS | __GFP_NOFAIL); + f2fs_bug_on(sbi, ret); + + spin_lock(&im->ino_lock); + slot = radix_tree_lookup_slot(&im->ino_root, index); + if (slot) { + entry = radix_tree_deref_slot(slot); + bitmap = xa_to_value(entry); + if (!(bitmap & (1UL << ofs))) { + bitmap |= (1UL << ofs); + entry = xa_mk_value(bitmap); + radix_tree_replace_slot(&im->ino_root, slot, entry); + } + } else { + bitmap |= (1UL << ofs); + entry = xa_mk_value(bitmap); + if (unlikely(radix_tree_insert(&im->ino_root, index, entry))) + f2fs_bug_on(sbi, 1); + } + spin_unlock(&im->ino_lock); + radix_tree_preload_end(); } void f2fs_remove_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int type) { - /* remove dirty ino entry from list */ - __remove_ino_entry(sbi, ino, type); + struct inode_management *im = &sbi->im[type]; + unsigned long index = INO_SLOT_INDEX(ino); + unsigned int ofs = INO_BIT_OFFSET(ino); + void **slot, *entry; + unsigned long bitmap; + + spin_lock(&im->ino_lock); + slot = radix_tree_lookup_slot(&im->ino_root, index); + if (slot) { + entry = radix_tree_deref_slot(slot); + bitmap = xa_to_value(entry); + if (bitmap & (1UL << ofs)) + bitmap &= ~(1UL << ofs); + + if (bitmap) { + entry = xa_mk_value(bitmap); + radix_tree_replace_slot(&im->ino_root, slot, entry); + } else { + radix_tree_delete(&im->ino_root, index); + } + } + spin_unlock(&im->ino_lock); } /* mode should be APPEND_INO, UPDATE_INO or TRANS_DIR_INO */ bool f2fs_exist_written_data(struct f2fs_sb_info *sbi, nid_t ino, int mode) { struct inode_management *im = &sbi->im[mode]; - struct ino_entry *e; + unsigned long index = INO_SLOT_INDEX(ino); + unsigned int ofs = INO_BIT_OFFSET(ino); + void *entry; + unsigned long bitmap; spin_lock(&im->ino_lock); - e = radix_tree_lookup(&im->ino_root, ino); + entry = radix_tree_lookup(&im->ino_root, index); + if (!entry) { + spin_unlock(&im->ino_lock); + return false; + } + bitmap = xa_to_value(entry); spin_unlock(&im->ino_lock); - return e ? true : false; + + return bitmap & (1UL << ofs); } void f2fs_release_ino_entry(struct f2fs_sb_info *sbi, bool all) @@ -804,7 +859,7 @@ void f2fs_release_ino_entry(struct f2fs_sb_info *sbi, bool all) struct ino_entry *e, *tmp; int i; - for (i = all ? ORPHAN_INO : APPEND_INO; i < MAX_INO_ENTRY; i++) { + for (i = all ? ORPHAN_INO : FLUSH_INO; i <= FLUSH_INO; i++) { struct inode_management *im = &sbi->im[i]; f2fs_wait_for_inode_record(sbi, i); @@ -818,6 +873,14 @@ void f2fs_release_ino_entry(struct f2fs_sb_info *sbi, bool all) } spin_unlock(&im->ino_lock); } + + for (i = APPEND_INO; i < MAX_INO_ENTRY; i++) { + struct inode_management *im = &sbi->im[i]; + + spin_lock(&im->ino_lock); + xa_destroy(&im->ino_root); + spin_unlock(&im->ino_lock); + } } void f2fs_set_dirty_device(struct f2fs_sb_info *sbi, nid_t ino, diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 54f9d3856b5c..a4c23b577ac9 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -389,14 +389,18 @@ enum { /* for the list of ino */ enum { ORPHAN_INO, /* for orphan ino list */ + FLUSH_INO, /* for multiple device flushing */ APPEND_INO, /* for append ino list */ UPDATE_INO, /* for update ino list */ TRANS_DIR_INO, /* for transactions dir ino list */ XATTR_DIR_INO, /* for xattr updated dir ino list */ - FLUSH_INO, /* for multiple device flushing */ MAX_INO_ENTRY, /* max. list */ }; +#define INO_BITS_PER_SLOT BITS_PER_XA_VALUE +#define INO_SLOT_INDEX(ino) ((ino) / INO_BITS_PER_SLOT) +#define INO_BIT_OFFSET(ino) ((ino) % INO_BITS_PER_SLOT) + struct ino_entry { struct list_head list; /* list head */ nid_t ino; /* inode number */ -- 2.49.0