From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: [PATCH] 1/3 Implement generic device DMA mapping support Date: Tue, 02 Mar 2004 16:23:48 +0100 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: References: <20040229223820.C17862@flint.arm.linux.org.uk> <20040301174517.J24955@flint.arm.linux.org.uk> <20040301182224.M24955@flint.arm.linux.org.uk> Mime-Version: 1.0 (generated by SEMI 1.14.5 - "Awara-Onsen") Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Russell King Cc: Jaroslav Kysela , Alsa Devel list List-Id: alsa-devel@alsa-project.org At Mon, 01 Mar 2004 19:34:57 +0100, I wrote: > > At Mon, 1 Mar 2004 18:22:24 +0000, > Russell King wrote: > > > > On Mon, Mar 01, 2004 at 06:51:56PM +0100, Takashi Iwai wrote: > > > a small concern about GFP_KERNEL is that i experienced the stall when > > > the kernel tried to allocate large continuous pages with GFP_KERNEL, > > > e.g. modprobe stops infinitely in the module init phase (and you > > > cannot even interrupt that process). > > > > > > does dma_alloc_coherent(GFP_KERNEL) with big pages work without stall? > > > > It depends where the stall was coming from. Do you have any further > > details? > > first of alll, i have to mention that it happend in the time of 2.4 > kernels. i've not tested with 2.6 kernels at all. > > a typical case was es1968 driver, which allocates the all buffer pages > at the initialization. when __get_free_pages() for 256MB with > GFP_KERNEL is called, it goes to sleep and never gets back. since > the context is uninterruptible, modprobe stucks and doesn't accept > SIGKILL. > > anyway, i need to this behavior again with the recent kernel. ok, i tested the new code now. it seems working fine without stall even for es1968 driver. the only problem is the call traces for each allocation like: modprobe: page allocation failure. order:8, mode:0xd0 Call Trace: [] __alloc_pages+0x2ec/0x300 [] __get_free_pages+0x18/0x30 ... i know it's just a warning but surely it's annoying if the caller knows the allocation may fail. it would be nice if we can shut it up. Takashi ------------------------------------------------------- SF.Net is sponsored by: Speed Start Your Linux Apps Now. Build and deploy apps & Web services for Linux with a free DVD software kit from IBM. Click Now! http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click