From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 ED41D152E04 for ; Tue, 9 Jul 2024 08:45:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720514706; cv=none; b=dlQzOouVCgPlt9qlHDJBjUYVedtuNWV/Vx3KQTDNPvXzQt6L+Dh1+It3UVsmOP1z2Sn1d7VH8w7rZFb6L1I0A4XLXc1SchAszGrDjFCYxnPUDLyA8EvGGhIEhqqcpO9lnujGIuVA1k4CHk8/P2E2LVl3p3BhYVDUlfwZgervp0o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720514706; c=relaxed/simple; bh=qXLhekIIlxj3jNGmdtcQpx1h4FQhxbC3rEZKQl/dwJE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NL4Tp3tHLZEMdBSTdDu+N6EnwMe1WavbniSselg1+gCfoISvq9r5+VRLmIB//l7BA68EfP2UHp838fysPwN8EDZlB6AFnYg+wtamY9uflOYQmSjd5Lw42kaULcaVoGBYD2K4K5HY4kJNtnoL+vXcgZS4LLvo+oh7QpMxRxQixsc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FizDL4ms; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="FizDL4ms" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 41096C3277B; Tue, 9 Jul 2024 08:45:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720514705; bh=qXLhekIIlxj3jNGmdtcQpx1h4FQhxbC3rEZKQl/dwJE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=FizDL4msF5tdF1c1h/MXNDlCvvdnN+5sk5lqksan2OqVLq/gNqCO7YNN9uo1F86Si V2ygNccvJtykvL6N/RTJkeO8sI/UXcKUcIu/D/BIWgtLfaQ+R204c0Na2ZAQaZSm0i MKCZCNdY+8lwjXYcZcO7tge62dL1ZH/lOPunYjwsN1QUb0JF7OsfOJXs9r4bdbcz/O tjO66q2fU7MFHRgvZ8PFu3o1MBnHn1KGRvkwbdizCjcvRRKR5NpU9CQ3Mf5k7NXZLZ m3X0Fv5659wEjqvr7k6K1CulVC1npPcugwqOe6j6d5gmj4Sd15FEb/d0G6lue+C+1d jivMx2TuJG9HQ== Date: Tue, 9 Jul 2024 11:42:20 +0300 From: Mike Rapoport To: Wei Yang Cc: akpm@linux-foundation.org, brauner@kernel.org, oleg@redhat.com, tandersen@netflix.com, mjguzik@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, David Hildenbrand Subject: Re: [PATCH v5 1/3] mm/memblock: introduce a new helper memblock_estimated_nr_free_pages() Message-ID: References: <20240709023609.21332-1-richard.weiyang@gmail.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: <20240709023609.21332-1-richard.weiyang@gmail.com> On Tue, Jul 09, 2024 at 02:36:07AM +0000, Wei Yang wrote: > During bootup, system may need the number of free pages in the whole system > to do some calculation before all pages are freed to buddy system. Usually > this number is get from totalram_pages(). Since we plan to move the free > pages accounting in __free_pages_core(), this value may not represent > total free pages at the early stage, especially when > CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled. > > Instead of using raw memblock api, let's introduce a new helper for user > to get the estimated number of free pages from memblock point of view. > > Signed-off-by: Wei Yang > CC: David Hildenbrand > Reviewed-by: David Hildenbrand Reviewed-by: Mike Rapoport > > --- > v5: cleanup the stale name > v4: adjust comment per david's suggestion > --- > include/linux/memblock.h | 1 + > mm/memblock.c | 17 +++++++++++++++++ > 2 files changed, 18 insertions(+) > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > index 40c62aca36ec..aba7ed9f2531 100644 > --- a/include/linux/memblock.h > +++ b/include/linux/memblock.h > @@ -486,6 +486,7 @@ static inline __init_memblock bool memblock_bottom_up(void) > > phys_addr_t memblock_phys_mem_size(void); > phys_addr_t memblock_reserved_size(void); > +unsigned long memblock_estimated_nr_free_pages(void); > phys_addr_t memblock_start_of_DRAM(void); > phys_addr_t memblock_end_of_DRAM(void); > void memblock_enforce_memory_limit(phys_addr_t memory_limit); > diff --git a/mm/memblock.c b/mm/memblock.c > index e81fb68f7f88..ae8e58fc4e7f 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -1729,6 +1729,23 @@ phys_addr_t __init_memblock memblock_reserved_size(void) > return memblock.reserved.total_size; > } > > +/** > + * memblock_estimated_nr_free_pages - return estimated number of free pages > + * from memblock point of view > + * > + * During bootup, subsystems might need a rough estimate of the number of free > + * pages in the whole system, before precise numbers are available from the > + * buddy. Especially with CONFIG_DEFERRED_STRUCT_PAGE_INIT, the numbers > + * obtained from the buddy might be very imprecise during bootup. > + * > + * Return: > + * An estimated number of free pages from memblock point of view. > + */ > +unsigned long __init memblock_estimated_nr_free_pages(void) > +{ > + return PHYS_PFN(memblock_phys_mem_size() - memblock_reserved_size()); > +} > + > /* lowest address */ > phys_addr_t __init_memblock memblock_start_of_DRAM(void) > { > -- > 2.34.1 > -- Sincerely yours, Mike.