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 AEC8E3043BE for ; Mon, 13 Jul 2026 09:32:05 +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=1783935126; cv=none; b=Rg26p36Ys8rRi3WJhW9tWrOSXvhxjUUyEymEFcCTFuDH1zkOb9NRmSe+Ex4MhIaqM6K6PrEV9vpbjR59i7Mf9A0fXEZuOxcya1M/kDNXCcB5wSL2eB7JjNoFm8v3CvdqeOm/oeLOMPBkH95vE/3Er6mU4oGA96DgMulrzW+WjCo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783935126; c=relaxed/simple; bh=nFFwYdItz3gV6J+FQDBAp7K/ohAMq0IGLglECyu5YnA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Pbcu6dcPNHgl8eNiQrGFNslK9dwizGr/CjNk5RWFg6XOGxSIVY/hkYk1zRgxa3y1me3Tj1RjQXMuHWignohR2PgXEXTBwnTYByORE2qUGvKBDN+6E5OyAy9esV28oxLY+f/3agjOBfQ+eA6PqSyX6POu8NCJqnPgWy6tj3MKFA0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=d4pW/fYB; 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="d4pW/fYB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36E911F000E9; Mon, 13 Jul 2026 09:31:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783935125; bh=8lhwsqOR9OYufkP9Jb1Vo4afPwabERH4nWOwiGvWRp8=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=d4pW/fYBkfgMCUljrGQAVHeKqZQBN0BBW6VRizcv2ahprCpKY8bmwK9c1ws/meNO0 yf3fDImFbMOL8rKkO4VQ7nccY/p8J+EWvEBRlkAaouQ/j4zuuiiWrEdiDwy23eofRK 98oU5N71VFEjrW6wbLZfxZFfh18hZqUFkwB22RY20j2K8uVZUsArXyCFtxqJaN6NMY KHaIuSkdQbVoV+8BVS1ccc5MKPknsIVm46iZGEf9IkuZK1TsE4O95aH0J5foydJcDx CIapPev3EIdba+E8RKdrnD1mDLFf3xpGZIfAhXpPyJ+L+FoFh4DhiJG4eB4ZluCdVv 9ugNcRnYc4XDw== Message-ID: Date: Mon, 13 Jul 2026 11:31:47 +0200 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] fs: stable_page_flags(): use folio_test_*() helpers To: Jinjiang Tu , akpm@linux-foundation.org, ziy@nvidia.com, luizcap@redhat.com, willy@infradead.org, linmiaohe@huawei.com, svetly.todorov@memverge.com, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Cc: wangkefeng.wang@huawei.com, sunnanyong@huawei.com References: <20260702110614.2176986-1-tujinjiang@huawei.com> <20260702110614.2176986-3-tujinjiang@huawei.com> <905c7dc9-a0d5-4b28-a899-53798fc4628e@kernel.org> <8b51832b-391d-4497-8135-8a3cdd4e4f57@huawei.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit On 7/13/26 08:58, Jinjiang Tu wrote: > > 在 2026/7/10 19:29, David Hildenbrand (Arm) 写道: >> On 7/2/26 13:06, Jinjiang Tu wrote: >>> stable_page_flags() currently accesses folio->flags.f directly. Since >>> commit 476d87d6a061 ("fs: stable_page_flags(): use snapshot_page()"), we >>> can replace these raw flag accesses with the existing folio_test_*() >>> helpers, thereby cleaning up the open‑coded flag handling. >>> >>> For KPF_IDLE, set_ps_flags() already handles both 64‑bit and 32‑bit >>> cases, so the duplicate code in stable_page_flags() that deals with >>> CONFIG_PAGE_IDLE_FLAG for the 64‑bit case is removed. >>> >>> The flag bits that has no folio_test_*() helpers are left unchanged, >>> including PG_owner_priv_1, PG_arch_*. >>> >>> No functional change is intended. >>> >>> Signed-off-by: Jinjiang Tu >>> --- >>>   fs/proc/page.c | 94 ++++++++++++++++++++++++++------------------------ >>>   1 file changed, 49 insertions(+), 45 deletions(-) >>> >>> diff --git a/fs/proc/page.c b/fs/proc/page.c >>> index 2717dbb0431b..0dbd46fa84ea 100644 >>> --- a/fs/proc/page.c >>> +++ b/fs/proc/page.c >>> @@ -148,8 +148,6 @@ u64 stable_page_flags(const struct page *page) >>>       const struct folio *folio; >>>       struct page_snapshot ps; >>>       unsigned long k; >>> -    unsigned long mapping; >>> -    bool is_anon; >>>       u64 u = 0; >>>         /* >>> @@ -163,17 +161,14 @@ u64 stable_page_flags(const struct page *page) >>>       folio = &ps.folio_snapshot; >>>         k = folio->flags.f; >>> -    mapping = (unsigned long)folio->mapping; >>> -    is_anon = mapping & FOLIO_MAPPING_ANON; >>> - >>>       /* >>>        * pseudo flags for the well known (anonymous) memory mapped pages >>>        */ >>>       if (folio_mapped(folio)) >>>           u |= BIT_ULL(KPF_MMAP); >>> -    if (is_anon) { >>> +    if (folio_test_anon(folio)) { >>>           u |= BIT_ULL(KPF_ANON); >>> -        if ((mapping & FOLIO_MAPPING_FLAGS) == FOLIO_MAPPING_KSM) >>> +        if (folio_test_ksm(folio)) >>>               u |= BIT_ULL(KPF_KSM); >>>       } >> These make sense. >> >>>   @@ -181,10 +176,12 @@ u64 stable_page_flags(const struct page *page) >>>        * compound pages: export both head/tail info >>>        * they together define a compound page's start/end pos and order >>>        */ >>> -    if (ps.idx == 0) >>> -        u |= kpf_copy_bit(k, KPF_COMPOUND_HEAD, PG_head); >>> -    else >>> +    if (ps.idx == 0) { >>> +        if (folio_test_head(folio)) >>> +            u |= BIT_ULL(KPF_COMPOUND_HEAD); >> >> Once we decouple folios from pages, we will have compound pages that are not >> folios. PG_head is not folio specific. >> >> But then, some of the flags below are used in other context outside of folios. >> >> I would focus here only on converting things to use folios that will actually be >> folio-specific: like the folio_test_anon() above. > > Understood, thanks. > > In addition to anon, ksm check, The swapcache check is also folio-specific. > > #define SWAPCACHE ((1 << PG_swapbacked) | (1 << PG_swapcache)) >     if ((k & SWAPCACHE) == SWAPCACHE) >         u |= 1 << KPF_SWAPCACHE; Indeed. that better also gets cleaned up. -- Cheers, David