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 1FB3022CBD0; Tue, 18 Feb 2025 09:47:11 +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=1739872032; cv=none; b=e2Mb7L/QmEcKkmmeo/7BPg27rNje2nC51l9KAXW0DKhr2WdTPhHVBWALxxJ2nx/wd6LSIbUUmldj2ydVRaQCKq69v0otRNomhX/9Oe2RPAFTMBoyjoxd0sLA/kMkNPpaZMerABnmpqX1FqhcBDEyIBbkdxVb/7aH0NwggZ0SGNA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739872032; c=relaxed/simple; bh=RewN5nlvJM/iiydEKFf80mM01NzWJ5mNu9D7+12YtFY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MkyUF6HnIOpBNYrYl8p4tabTZwjTfF9B9b6fvO2Fd46vHkGmJIs4qPeyfLWM5AjHTUOqIOpf5i1BbfaP0DW2oq81Uedq5iag20NfBnxSg403odC1Tq67fwlsV+r0N6UxlE9lQe/IbdJd6Y1XIfIYtqssALDeVZw/y6GlkhsNhG8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WxYr3p8+; 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="WxYr3p8+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09C41C4CEE2; Tue, 18 Feb 2025 09:47:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739872031; bh=RewN5nlvJM/iiydEKFf80mM01NzWJ5mNu9D7+12YtFY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WxYr3p8+ONFGwBoe1iFxQlwIolL1Cznbq8f6dhKX94nIMMeQSNMLuJ4TNF4oqUsDg di2QHX3OtREUPToYGwHEvIPPF/psJiHmlT3rKLI0NHX1ZUmJ6m2tbyN1bWv2rIrxcf 7mFDdcFWUQaCtf6tLCHuPWdpg+2TzUz0U8s9BGZ0FtLtb73kSwApNfMoN2r3wifvzC KM3iXPsoh/LeRxt7ksvSTpiWTdyoPtWr1IFjeLhin+RLl9zT3etYaoijloF4PJhaQJ 5lGSC9GRKfalcPp7pRzRF9BzF0IZ5meUM6mrcKz68sY7tOQ42muFf1IBeKDS2QmDTN ZeDmaT0MZD6KQ== Date: Tue, 18 Feb 2025 11:47:05 +0200 From: Mike Rapoport To: Masami Hiramatsu Cc: Steven Rostedt , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Mark Rutland , Mathieu Desnoyers , Andrew Morton Subject: Re: [PATCH v3 1/2] mm/memblock: Add reserved memory release function Message-ID: References: <173928521419.906035.17750338150436695675.stgit@devnote2> <173928522350.906035.5626965043208329135.stgit@devnote2> <20250218174257.61018735a30268b5e21e50e3@kernel.org> 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: <20250218174257.61018735a30268b5e21e50e3@kernel.org> On Tue, Feb 18, 2025 at 05:42:57PM +0900, Masami Hiramatsu wrote: > Hi Mike, > > On Tue, 18 Feb 2025 09:24:53 +0200 > Mike Rapoport wrote: > > > Hi Masami, > > > > On Tue, Feb 11, 2025 at 11:47:03PM +0900, Masami Hiramatsu (Google) wrote: > > > From: Masami Hiramatsu (Google) > > > > > > Add reserve_mem_release_by_name() to release a reserved memory region > > > with a given name. This allows us to release reserved memory which is > > > defined by kernel cmdline, after boot. > > > > > > Signed-off-by: Masami Hiramatsu (Google) > > > Cc: Andrew Morton > > > Cc: Mike Rapoport > > > Cc: linux-mm@kvack.org > > > > ... > > > > > +/** > > > + * reserve_mem_release_by_name - Release reserved memory region with a given name > > > + * @name: The name that is attatched to a reserved memory region > > > + * > > > + * Forcibly release the pages in the reserved memory region so that those memory > > > + * can be used as free memory. After released the reserved region size becomes 0. > > > + * > > > + * Returns: 1 if released or 0 if not found. > > > + */ > > > +int reserve_mem_release_by_name(const char *name) > > > +{ > > > + struct reserve_mem_table *map; > > > + unsigned int page_count; > > > + phys_addr_t start; > > > + > > > + guard(mutex)(&reserve_mem_lock); > > > + map = reserve_mem_find_by_name_nolock(name); > > > + if (!map) > > > + return 0; > > > + > > > + start = map->start; > > > + page_count = DIV_ROUND_UP(map->size, PAGE_SIZE); > > > + > > > + for (int i = 0; i < page_count; i++) { > > > + phys_addr_t addr = start + i * PAGE_SIZE; > > > + struct page *page = pfn_to_page(addr >> PAGE_SHIFT); > > > + > > > + page->flags &= ~BIT(PG_reserved); > > > + __free_page(page); > > > + } > > > > We have free_reserved_area(), please use it here. > > Otherwise > > > > Acked-by: Mike Rapoport (Microsoft) > > Thanks! but I can not use free_reserved_area() here because it uses > virt_to_page(). Here we only know the physical address in the map. > I think we can use free_reserved_page() instead. Is that OK? For reserve_mem ranges virt_to_phys() will work, they are allocated from the memory that is covered by the direct map. > Thank you, > > -- > Masami Hiramatsu (Google) -- Sincerely yours, Mike.