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 DD19D28C86C for ; Tue, 30 Jun 2026 07:38:03 +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=1782805085; cv=none; b=dJ3TeA5U+40II2dRlZoyi7y0R5Z3dtNN/q05eKUb1OK1RsQZaAQPRS5ib4EVzBIOTOsNYAdR9In20N3VUqbT1PkWdz30DgUSrvAGbE1wzuW12fNHJf6+sFOcy059rRsrEf4kt6UOomi6DPcdJghs2nupp2PMU6tdxiIwpS9frF4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782805085; c=relaxed/simple; bh=rWMC8PvQAQGsOxTjfpjb7qC2fGbLu/mL+cKFJ/mQvwU=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=jfV4sX73o13PBwjs2aOCBw2qVAYS1rm3Eec2rxoNIMqt78bo76WQHmBVWewy50QzONtS8oYxVyB6umQlRXy4GM0PZEbfrWnIeeoXE2F0rcSxdF764GoY2465p0hragdmuFbcOrN5DIadmBeetRjBdMB5TEe9vv9HwbSKhTD0JhY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZaepFvs+; 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="ZaepFvs+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C18021F000E9; Tue, 30 Jun 2026 07:38:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782805083; bh=x1jC54PzF/F4uOMvoowBaR3ySGT8vXIPNFJPlFN4gUQ=; h=Date:Cc:Subject:To:References:From:In-Reply-To; b=ZaepFvs+UVbbEk4YlHhPZ5UiDbHudsXpDC0tHPNqHlLUdR+bHZUDmiUptBA53zom8 QrbYBrWtG5h2diO3ovfK6Faq4FrwRs4GZ/2p3Lz1PZy2eAq7DTwqY5rMYQEaqYNP++ kjmMa4bnqJgFVDh6T/bEp3d/4m/daY35htIoQIUx6KzmPOmAOcDVu0+T2xo9P9Qzuf wND8az0HW+ok+eom3a+Jfs+XTnJffl9N/cyHOIaq3b1x+3aoTN0hkzvftqtlmLG6tc YiVgdp+lUwN0xBGVQMbO1QYEUHoVS/sE9MBx8pvfGHm22hACpPkRHlzLHRHDMMHB3h yNKgTIbGlDuGg== Message-ID: Date: Tue, 30 Jun 2026 15:37:58 +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 Cc: chao@kernel.org, linux-kernel@vger.kernel.org, Barry Song , Ryan Roberts , Juan Yescas , Dev Jain , David Hildenbrand , Pengfei Li , Bo Zhang , Kalesh Singh , Jaegeuk Kim Subject: Re: [f2fs-dev] [RFC PATCH v2 01/10] f2fs: extend folio state for large folio write path To: Nanzhe Zhao , linux-f2fs-devel@lists.sourceforge.net References: <20260622160830.324455-1-zhaonanzhe@xiaomi.com> <20260622160830.324455-2-zhaonanzhe@xiaomi.com> Content-Language: en-US From: Chao Yu In-Reply-To: <20260622160830.324455-2-zhaonanzhe@xiaomi.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/23/26 00:08, Nanzhe Zhao wrote: > Large folio write path needs a subpage status bitmap and write > pages pending counter, while keeping compatible with f2fs private > flags. > > Move struct f2fs_folio_state to f2fs.h, add private_flags and > subpage state bitmap, and change PAGE_PRIVATE functions to be > compatible with f2fs_folio_state. Allocate f2fs_folio_state via kzalloc > instead of kmem_cache, since the state size depends on the folio order. > > Note: Now if a path wants to use f2fs_folio_state, it must call > `folio_has_ffs` instead of `folio_test_large`` to make check. > > Signed-off-by: Nanzhe Zhao > --- > fs/f2fs/compress.c | 2 ++ > fs/f2fs/data.c | 46 ++++++++++++++++---------------- > fs/f2fs/f2fs.h | 66 ++++++++++++++++++++++++++++++++++++++-------- > 3 files changed, 80 insertions(+), 34 deletions(-) > > diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c > index 91855d91bbdd..de1305fcc6c1 100644 > --- a/fs/f2fs/compress.c > +++ b/fs/f2fs/compress.c > @@ -76,6 +76,8 @@ bool f2fs_is_compressed_page(struct folio *folio) > { > if (!folio->private) > return false; > + if (folio_has_ffs(folio)) > + return false; > if (folio_test_f2fs_nonpointer(folio)) > return false; private is a pointer for compressed page, so it will be better to check folio_test_f2fs_nonpointer() first, and then folio_has_ffs(). if (folio_test_f2fs_nonpointer(folio)) return false; if (folio_has_ffs(folio)) return false; > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index ac1cf4de3d62..23758c00758d 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -32,20 +32,13 @@ > > static struct kmem_cache *bio_post_read_ctx_cache; > static struct kmem_cache *bio_entry_slab; > -static struct kmem_cache *ffs_entry_slab; > static mempool_t *bio_post_read_ctx_pool; > static struct bio_set f2fs_bioset; > > -struct f2fs_folio_state { > - spinlock_t state_lock; > - unsigned int read_pages_pending; > -}; > - > struct f2fs_bio { > struct work_struct work; > struct bio bio; > }; > - > #define F2FS_BIO_POOL_SIZE NR_CURSEG_TYPE > > int __init f2fs_init_bioset(void) > @@ -2514,15 +2507,30 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret, > > static struct f2fs_folio_state *ffs_find_or_alloc(struct folio *folio) > { > - struct f2fs_folio_state *ffs = folio->private; > + struct f2fs_folio_state *ffs; > + unsigned int nr_subpages = folio_nr_pages(folio); > + unsigned long private_flags = 0; > > - if (ffs) > - return ffs; > + f2fs_bug_on(F2FS_F_SB(folio), !folio_test_large(folio)); > > - ffs = f2fs_kmem_cache_alloc(ffs_entry_slab, > - GFP_NOIO | __GFP_ZERO, true, NULL); > + if (folio_has_ffs(folio)) > + return (struct f2fs_folio_state *)folio->private; > + > + if (folio_test_private(folio) && folio_test_f2fs_nonpointer(folio)) Why this can happen? allocating large folio from other paths? > + private_flags = (unsigned long)folio->private; > + > + ffs = kzalloc(struct_size(ffs, state, BITS_TO_LONGS(2 * nr_subpages)), > + GFP_NOIO | __GFP_NOFAIL); > > spin_lock_init(&ffs->state_lock); > + ffs->private_flags = private_flags; > + if (folio_test_uptodate(folio)) > + bitmap_set(ffs->state, 0, nr_subpages); > + if (folio_test_dirty(folio)) > + bitmap_set(ffs->state, nr_subpages, nr_subpages); Can you describe ffs->state layout in its definition? > + > + if (folio_test_private(folio)) > + folio_detach_private(folio); > folio_attach_private(folio, ffs); > return ffs; > } > @@ -2531,7 +2539,7 @@ static void ffs_detach_free(struct folio *folio) > { > struct f2fs_folio_state *ffs; > > - if (!folio_test_large(folio)) { > + if (!folio_has_ffs(folio)) { > folio_detach_private(folio); > return; > } > @@ -2541,7 +2549,8 @@ static void ffs_detach_free(struct folio *folio) > return; > > WARN_ON_ONCE(ffs->read_pages_pending != 0); > - kmem_cache_free(ffs_entry_slab, ffs); > + WARN_ON_ONCE(atomic_read(&ffs->write_pages_pending)); > + kfree(ffs); > } > > static int f2fs_read_data_large_folio(struct inode *inode, > @@ -4571,21 +4580,12 @@ int __init f2fs_init_bio_entry_cache(void) > if (!bio_entry_slab) > return -ENOMEM; > > - ffs_entry_slab = f2fs_kmem_cache_create("f2fs_ffs_slab", > - sizeof(struct f2fs_folio_state)); > - > - if (!ffs_entry_slab) { > - kmem_cache_destroy(bio_entry_slab); > - return -ENOMEM; > - } > - > return 0; > } > > void f2fs_destroy_bio_entry_cache(void) > { > kmem_cache_destroy(bio_entry_slab); > - kmem_cache_destroy(ffs_entry_slab); > } > > static int f2fs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index f1774d4e18d2..e4778c17394e 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -1620,6 +1620,15 @@ static inline void f2fs_clear_bit(unsigned int nr, char *addr); > * Layout B: lowest bit should be 0 > * page.private is a wrapped pointer. > */ > + > +struct f2fs_folio_state { > + spinlock_t state_lock; > + unsigned int read_pages_pending; > + atomic_t write_pages_pending; > + unsigned long private_flags; > + unsigned long state[]; > +}; > + > enum { > PAGE_PRIVATE_NOT_POINTER, /* private contains non-pointer data */ > PAGE_PRIVATE_ONGOING_MIGRATION, /* data page which is on-going migrating */ > @@ -1629,6 +1638,14 @@ enum { > PAGE_PRIVATE_MAX > }; > > +static inline bool folio_has_ffs(const struct folio *folio) > +{ > + unsigned long private = (unsigned long)folio->private; > + > + return folio_test_large(folio) && private && > + !(private & BIT(PAGE_PRIVATE_NOT_POINTER)); > +} > + > /* For compression */ > enum compress_algorithm_type { > COMPRESS_LZO, > @@ -2638,9 +2655,15 @@ static inline int inc_valid_block_count(struct f2fs_sb_info *sbi, > #define PAGE_PRIVATE_GET_FUNC(name, flagname) \ > static inline bool folio_test_f2fs_##name(const struct folio *folio) \ Seems there are redundant codes below, let's have a try to wrap them w/ a macro for cleanup? > { \ > - unsigned long priv = (unsigned long)folio->private; \ > + unsigned long priv; \ > unsigned long v = (1UL << PAGE_PRIVATE_NOT_POINTER) | \ > (1UL << PAGE_PRIVATE_##flagname); \ > + if (folio_has_ffs(folio)) { \ > + struct f2fs_folio_state *ffs = folio->private; \ > + priv = ffs->private_flags; \ > + } else { \ > + priv = (unsigned long)folio->private; \ > + } \ > return (priv & v) == v; \ > } \ > static inline bool page_private_##name(struct page *page) \ > @@ -2655,7 +2678,10 @@ static inline void folio_set_f2fs_##name(struct folio *folio) \ > { \ > unsigned long v = (1UL << PAGE_PRIVATE_NOT_POINTER) | \ > (1UL << PAGE_PRIVATE_##flagname); \ > - if (!folio->private) \ > + if (folio_has_ffs(folio)) { \ > + struct f2fs_folio_state *ffs = folio->private; \ > + ffs->private_flags |= v; \ > + } else if (!folio->private) \ > folio_attach_private(folio, (void *)v); \ Ditto? > else { \ > v |= (unsigned long)folio->private; \ > @@ -2673,13 +2699,18 @@ static inline void set_page_private_##name(struct page *page) \ > #define PAGE_PRIVATE_CLEAR_FUNC(name, flagname) \ > static inline void folio_clear_f2fs_##name(struct folio *folio) \ > { \ > - unsigned long v = (unsigned long)folio->private; \ > + if (folio_has_ffs(folio)) { \ > + struct f2fs_folio_state *ffs = folio->private; \ > + ffs->private_flags &= ~(1UL << PAGE_PRIVATE_##flagname); \ > + } else { \ > + unsigned long v = (unsigned long)folio->private; \ > \ > - v &= ~(1UL << PAGE_PRIVATE_##flagname); \ > - if (v == (1UL << PAGE_PRIVATE_NOT_POINTER)) \ > - folio_detach_private(folio); \ > - else \ > - folio->private = (void *)v; \ > + v &= ~(1UL << PAGE_PRIVATE_##flagname); \ > + if (v == (1UL << PAGE_PRIVATE_NOT_POINTER)) \ > + folio_detach_private(folio); \ > + else \ > + folio->private = (void *)v; \ > + } \ > } \ > static inline void clear_page_private_##name(struct page *page) \ > { \ > @@ -2705,7 +2736,15 @@ PAGE_PRIVATE_CLEAR_FUNC(atomic, ATOMIC_WRITE); > > static inline unsigned long folio_get_f2fs_data(struct folio *folio) > { > - unsigned long data = (unsigned long)folio->private; > + unsigned long data; > + > + if (folio_has_ffs(folio)) { > + struct f2fs_folio_state *ffs = folio->private; > + > + data = ffs->private_flags; > + } else { > + data = (unsigned long)folio->private; > + } Ditto? > > if (!test_bit(PAGE_PRIVATE_NOT_POINTER, &data)) > return 0; > @@ -2716,10 +2755,15 @@ static inline void folio_set_f2fs_data(struct folio *folio, unsigned long data) > { > data = (1UL << PAGE_PRIVATE_NOT_POINTER) | (data << PAGE_PRIVATE_MAX); > > - if (!folio_test_private(folio)) > + if (folio_has_ffs(folio)) { > + struct f2fs_folio_state *ffs = folio->private; > + > + ffs->private_flags |= data; > + } else if (!folio_test_private(folio)) { > folio_attach_private(folio, (void *)data); Ditto? Thanks, > - else > + } else { > folio->private = (void *)((unsigned long)folio->private | data); > + } > } > > static inline void dec_valid_block_count(struct f2fs_sb_info *sbi,