From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 CFE1025F7A2; Thu, 27 Feb 2025 15:14:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740669272; cv=none; b=beXBUmx28wzdrbgRjw9T/tziFVNqLClDRIM0GcTRdjDUTR/+pD5LU5GclXLz5eN31+KYjpCt14/79Xn6rQh1tZGzKTVNQGziRvIvugcQToyInybFUDZEc+9oVq1Ln3s8oik03iYa8+Zf4j9tYHJ54jHvtawiCr0vZIXZrT2iPq0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740669272; c=relaxed/simple; bh=cVSgDCggYpw8xN5dH8v583jJU/1xhO0S9v5k3RuLRuc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NGrsiM7AzXhcUdq2k7vHK9dURoPZ2wPMxbkDqtYpTRx0MjjWKHL/xzOwtGvGOKlN9N7M0ASOxyaPy1swIvjeJTvVuCcFi2wBZjxUoFTrxFT6/ACBGp4vN/ETj/BD8owwNRaPbQw9j0RnDLnSPdVtunJKsEr1QkUYwOLmI1yeIzE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=XJ4ZUnqj; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="XJ4ZUnqj" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ZG1Z/AvQvy2Nn3Xs8i93g3gloTg9fkysRZ6eqtmzy+k=; b=XJ4ZUnqjgLZkjeds3l3Ic0yv1U ObWbqQi6a6BVYlVNqnxDtt6v37SdHaPvrZ4WvucLlDkmwBNF5rVBaagjMv7SAP5A0VHRZqP8VM4zF Ulf9Mu+bTr7XlUC/vk40Z4an/G073wAhtzOI3kWlh6xrJzGQAOB1I7bdtJXWAXjcsnH9kImMFWda0 KrmcC5e1VfO/+8P8gLZIqGEVHIUmbrTOT51JakD1/1lobLxEbwUx2GLQDYbhkx8B6QhYqjHEJSQNB 8jULkx0X1hMsTiNPE5nsVuzZKQX4K29Sw1fWklz1jt55EUUyZFnCJ4bl2pEpbS58sJDkcpwJwnkwv yL0wZQOA==; Received: from willy by casper.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tnfaO-000000009ty-35Id; Thu, 27 Feb 2025 15:14:05 +0000 Date: Thu, 27 Feb 2025 15:14:04 +0000 From: Matthew Wilcox To: Zi Yan Cc: linux-mm@kvack.org, Andrew Morton , "Kirill A . Shutemov" , Ryan Roberts , Hugh Dickins , David Hildenbrand , Yang Shi , Miaohe Lin , Kefeng Wang , Yu Zhao , John Hubbard , Baolin Wang , linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Kairui Song Subject: Re: [PATCH v9 2/8] mm/huge_memory: add two new (not yet used) functions for folio_split() Message-ID: References: <20250226210032.2044041-1-ziy@nvidia.com> <20250226210032.2044041-3-ziy@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Feb 27, 2025 at 05:55:43AM +0000, Matthew Wilcox wrote: > On Wed, Feb 26, 2025 at 04:00:25PM -0500, Zi Yan wrote: > > +static int __split_unmapped_folio(struct folio *folio, int new_order, > > + struct page *split_at, struct page *lock_at, > > + struct list_head *list, pgoff_t end, > > + struct xa_state *xas, struct address_space *mapping, > > + bool uniform_split) > > +{ > [...] > > + /* complete memcg works before add pages to LRU */ > > + split_page_memcg(&folio->page, old_order, split_order); > > + split_page_owner(&folio->page, old_order, split_order); > > + pgalloc_tag_split(folio, old_order, split_order); > > At least split_page_memcg() needs to become aware of 'uniform_split'. > > if (folio_memcg_kmem(folio)) > obj_cgroup_get_many(__folio_objcg(folio), old_nr / new_nr - 1); > > If we're doing uniform_split, that calculation should be > old_order - new_order - 1 umm, old_order - new_order. Anyway, here's a patch I've done on top of your work, but it probably needs to be massaged slightly and placed before your work? >From 190e13ed77e562eb59fa1fa4bfefdefe5d0416ed Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 28 Oct 2024 16:23:30 -0400 Subject: [PATCH] mm: Separate folio_split_memcg() from split_page_memcg() Folios always use memcg_data to refer to the mem_cgroup while pages allocated with GFP_ACCOUNT have a pointer to the obj_cgroup. Since the caller already knows what it has, split the function into two and then we don't need to check. Signed-off-by: Matthew Wilcox (Oracle) --- include/linux/memcontrol.h | 7 +++++++ mm/huge_memory.c | 6 ++++-- mm/memcontrol.c | 18 +++++++++++++++--- 3 files changed, 26 insertions(+), 5 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 57664e2a8fb7..155c3f81f4df 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1039,6 +1039,8 @@ static inline void memcg_memory_event_mm(struct mm_struct *mm, } void split_page_memcg(struct page *head, int old_order, int new_order); +void folio_split_memcg(struct folio *folio, unsigned old_order, + unsigned new_order, bool uniform_split); static inline u64 cgroup_id_from_mm(struct mm_struct *mm) { @@ -1463,6 +1465,11 @@ static inline void split_page_memcg(struct page *head, int old_order, int new_or { } +static inline void folio_split_memcg(struct folio *folio, unsigned old_order, + unsigned new_order, bool uniform) +{ +} + static inline u64 cgroup_id_from_mm(struct mm_struct *mm) { return 0; diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 1e45064046a0..75fa9c9d9ec9 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3401,6 +3401,9 @@ static void __split_folio_to_order(struct folio *folio, int new_order) folio_set_young(new_folio); if (folio_test_idle(folio)) folio_set_idle(new_folio); +#ifdef CONFIG_MEMCG + new_folio->memcg_data = folio->memcg_data; +#endif folio_xchg_last_cpupid(new_folio, folio_last_cpupid(folio)); } @@ -3529,8 +3532,7 @@ static int __split_unmapped_folio(struct folio *folio, int new_order, } } - /* complete memcg works before add pages to LRU */ - split_page_memcg(&folio->page, old_order, split_order); + folio_split_memcg(folio, old_order, split_order, uniform_split); split_page_owner(&folio->page, old_order, split_order); pgalloc_tag_split(folio, old_order, split_order); diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 16f3bdbd37d8..c2d41e1337cb 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3064,10 +3064,22 @@ void split_page_memcg(struct page *head, int old_order, int new_order) for (i = new_nr; i < old_nr; i += new_nr) folio_page(folio, i)->memcg_data = folio->memcg_data; - if (folio_memcg_kmem(folio)) - obj_cgroup_get_many(__folio_objcg(folio), old_nr / new_nr - 1); + obj_cgroup_get_many(__folio_objcg(folio), old_nr / new_nr - 1); +} + +void folio_split_memcg(struct folio *folio, unsigned old_order, + unsigned new_order, bool uniform_split) +{ + unsigned new_refs; + + if (mem_cgroup_disabled() || !folio_memcg_charged(folio)) + return; + + if (uniform_split) + new_refs = (1 << (old_order - new_order)) - 1; else - css_get_many(&folio_memcg(folio)->css, old_nr / new_nr - 1); + new_refs = old_order - new_order; + css_get_many(&__folio_memcg(folio)->css, new_refs); } unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) -- 2.47.2