Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758752AbYHZUIO (ORCPT ); Tue, 26 Aug 2008 16:08:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753422AbYHZUH7 (ORCPT ); Tue, 26 Aug 2008 16:07:59 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:59081 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753335AbYHZUH5 (ORCPT ); Tue, 26 Aug 2008 16:07:57 -0400 Date: Tue, 26 Aug 2008 13:06:18 -0700 (PDT) From: Linus Torvalds To: Jeff Garzik , Auke Kok , Jeff Kirsher cc: Rusty Russell , "Alan D. Brunelle" , "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List , Andrew Morton , Arjan van de Ven , Ingo Molnar Subject: e1000 horridness (was Re: [Bug #11342] Linux 2.6.27-rc3: kernel BUG at mm/vmalloc.c - bisected) In-Reply-To: <48B45FA2.8040603@garzik.org> Message-ID: References: <48B313E0.1000501@hp.com> <200808261111.19205.rusty@rustcorp.com.au> <48B45FA2.8040603@garzik.org> User-Agent: Alpine 1.10 (LFD 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9841 Lines: 292 On Tue, 26 Aug 2008, Jeff Garzik wrote: > > e1000_check_options builds a struct (singular) on the stack, really... struct > e1000_option is reasonably small. No it doesn't. Look a bit more closely. It builds a struct (singular) MANY MANY times. It also then builds up a huge e1000_opt_list[] array, even though it is const and should be static (and const). I know. I wrote a patch to FIX it. Here's the patch. It shrinks the stack from 1152 bytes to 192 bytes (the first version, that only did the e1000_option part, got it down to 600 bytes). About half comes from not using multiple "e1000_option" structures, the other half comes from turning the "e1000_opt_list[]" arrays into "static const" instead, so that gcc doesn't copy them onto the stack. Most of the patch is actually doing things like turning struct struct e1000_option opt = { (which declares a _new_ e1000_option variable each time) into opt = (struct e1000_option) { which just re-uses the single variable. It becomes slightly larger than that, because some places the "opt = .." had to be moved around, since it's no longer a variable declaration, but a regular assignment. The rest is just adding "const" to the right places, and turning struct e1000_opt_list speed_list[] = .. into static const struct e1000_opt_list speed_list[] = .. instead, and fixing the indentation to be more straightforward. I have not tested the dang thing, but I think it's correct. And it turns stack usage from "totally horrible and broken" into "pretty reasonable". Linus --- drivers/net/e1000/e1000_param.c | 81 +++++++++++++++++++++----------------- 1 files changed, 45 insertions(+), 36 deletions(-) diff --git a/drivers/net/e1000/e1000_param.c b/drivers/net/e1000/e1000_param.c index b9f90a5..213437d 100644 --- a/drivers/net/e1000/e1000_param.c +++ b/drivers/net/e1000/e1000_param.c @@ -208,7 +208,7 @@ struct e1000_option { } r; struct { /* list_option info */ int nr; - struct e1000_opt_list { int i; char *str; } *p; + const struct e1000_opt_list { int i; char *str; } *p; } l; } arg; }; @@ -242,7 +242,7 @@ static int __devinit e1000_validate_option(unsigned int *value, break; case list_option: { int i; - struct e1000_opt_list *ent; + const struct e1000_opt_list *ent; for (i = 0; i < opt->arg.l.nr; i++) { ent = &opt->arg.l.p[i]; @@ -279,7 +279,9 @@ static void e1000_check_copper_options(struct e1000_adapter *adapter); void __devinit e1000_check_options(struct e1000_adapter *adapter) { + struct e1000_option opt; int bd = adapter->bd_number; + if (bd >= E1000_MAX_NIC) { DPRINTK(PROBE, NOTICE, "Warning: no configuration for board #%i\n", bd); @@ -287,19 +289,21 @@ void __devinit e1000_check_options(struct e1000_adapter *adapter) } { /* Transmit Descriptor Count */ - struct e1000_option opt = { + struct e1000_tx_ring *tx_ring = adapter->tx_ring; + int i; + e1000_mac_type mac_type = adapter->hw.mac_type; + + opt = (struct e1000_option) { .type = range_option, .name = "Transmit Descriptors", .err = "using default of " __MODULE_STRING(E1000_DEFAULT_TXD), .def = E1000_DEFAULT_TXD, - .arg = { .r = { .min = E1000_MIN_TXD }} + .arg = { .r = { + .min = E1000_MIN_TXD, + .max = mac_type < e1000_82544 ? E1000_MAX_TXD : E1000_MAX_82544_TXD + }} }; - struct e1000_tx_ring *tx_ring = adapter->tx_ring; - int i; - e1000_mac_type mac_type = adapter->hw.mac_type; - opt.arg.r.max = mac_type < e1000_82544 ? - E1000_MAX_TXD : E1000_MAX_82544_TXD; if (num_TxDescriptors > bd) { tx_ring->count = TxDescriptors[bd]; @@ -313,19 +317,21 @@ void __devinit e1000_check_options(struct e1000_adapter *adapter) tx_ring[i].count = tx_ring->count; } { /* Receive Descriptor Count */ - struct e1000_option opt = { + struct e1000_rx_ring *rx_ring = adapter->rx_ring; + int i; + e1000_mac_type mac_type = adapter->hw.mac_type; + + opt = (struct e1000_option) { .type = range_option, .name = "Receive Descriptors", .err = "using default of " __MODULE_STRING(E1000_DEFAULT_RXD), .def = E1000_DEFAULT_RXD, - .arg = { .r = { .min = E1000_MIN_RXD }} + .arg = { .r = { + .min = E1000_MIN_RXD, + .max = mac_type < e1000_82544 ? E1000_MAX_RXD : E1000_MAX_82544_RXD + }} }; - struct e1000_rx_ring *rx_ring = adapter->rx_ring; - int i; - e1000_mac_type mac_type = adapter->hw.mac_type; - opt.arg.r.max = mac_type < e1000_82544 ? E1000_MAX_RXD : - E1000_MAX_82544_RXD; if (num_RxDescriptors > bd) { rx_ring->count = RxDescriptors[bd]; @@ -339,7 +345,7 @@ void __devinit e1000_check_options(struct e1000_adapter *adapter) rx_ring[i].count = rx_ring->count; } { /* Checksum Offload Enable/Disable */ - struct e1000_option opt = { + opt = (struct e1000_option) { .type = enable_option, .name = "Checksum Offload", .err = "defaulting to Enabled", @@ -363,7 +369,7 @@ void __devinit e1000_check_options(struct e1000_adapter *adapter) { E1000_FC_FULL, "Flow Control Enabled" }, { E1000_FC_DEFAULT, "Flow Control Hardware Default" }}; - struct e1000_option opt = { + opt = (struct e1000_option) { .type = list_option, .name = "Flow Control", .err = "reading default settings from EEPROM", @@ -381,7 +387,7 @@ void __devinit e1000_check_options(struct e1000_adapter *adapter) } } { /* Transmit Interrupt Delay */ - struct e1000_option opt = { + opt = (struct e1000_option) { .type = range_option, .name = "Transmit Interrupt Delay", .err = "using default of " __MODULE_STRING(DEFAULT_TIDV), @@ -399,7 +405,7 @@ void __devinit e1000_check_options(struct e1000_adapter *adapter) } } { /* Transmit Absolute Interrupt Delay */ - struct e1000_option opt = { + opt = (struct e1000_option) { .type = range_option, .name = "Transmit Absolute Interrupt Delay", .err = "using default of " __MODULE_STRING(DEFAULT_TADV), @@ -417,7 +423,7 @@ void __devinit e1000_check_options(struct e1000_adapter *adapter) } } { /* Receive Interrupt Delay */ - struct e1000_option opt = { + opt = (struct e1000_option) { .type = range_option, .name = "Receive Interrupt Delay", .err = "using default of " __MODULE_STRING(DEFAULT_RDTR), @@ -435,7 +441,7 @@ void __devinit e1000_check_options(struct e1000_adapter *adapter) } } { /* Receive Absolute Interrupt Delay */ - struct e1000_option opt = { + opt = (struct e1000_option) { .type = range_option, .name = "Receive Absolute Interrupt Delay", .err = "using default of " __MODULE_STRING(DEFAULT_RADV), @@ -453,7 +459,7 @@ void __devinit e1000_check_options(struct e1000_adapter *adapter) } } { /* Interrupt Throttling Rate */ - struct e1000_option opt = { + opt = (struct e1000_option) { .type = range_option, .name = "Interrupt Throttling Rate (ints/sec)", .err = "using default of " __MODULE_STRING(DEFAULT_ITR), @@ -497,7 +503,7 @@ void __devinit e1000_check_options(struct e1000_adapter *adapter) } } { /* Smart Power Down */ - struct e1000_option opt = { + opt = (struct e1000_option) { .type = enable_option, .name = "PHY Smart Power Down", .err = "defaulting to Disabled", @@ -513,7 +519,7 @@ void __devinit e1000_check_options(struct e1000_adapter *adapter) } } { /* Kumeran Lock Loss Workaround */ - struct e1000_option opt = { + opt = (struct e1000_option) { .type = enable_option, .name = "Kumeran Lock Loss Workaround", .err = "defaulting to Enabled", @@ -578,16 +584,18 @@ static void __devinit e1000_check_fiber_options(struct e1000_adapter *adapter) static void __devinit e1000_check_copper_options(struct e1000_adapter *adapter) { + struct e1000_option opt; unsigned int speed, dplx, an; int bd = adapter->bd_number; { /* Speed */ - struct e1000_opt_list speed_list[] = {{ 0, "" }, - { SPEED_10, "" }, - { SPEED_100, "" }, - { SPEED_1000, "" }}; + static const struct e1000_opt_list speed_list[] = { + { 0, "" }, + { SPEED_10, "" }, + { SPEED_100, "" }, + { SPEED_1000, "" }}; - struct e1000_option opt = { + opt = (struct e1000_option) { .type = list_option, .name = "Speed", .err = "parameter ignored", @@ -604,11 +612,12 @@ static void __devinit e1000_check_copper_options(struct e1000_adapter *adapter) } } { /* Duplex */ - struct e1000_opt_list dplx_list[] = {{ 0, "" }, - { HALF_DUPLEX, "" }, - { FULL_DUPLEX, "" }}; + static const struct e1000_opt_list dplx_list[] = { + { 0, "" }, + { HALF_DUPLEX, "" }, + { FULL_DUPLEX, "" }}; - struct e1000_option opt = { + opt = (struct e1000_option) { .type = list_option, .name = "Duplex", .err = "parameter ignored", @@ -637,7 +646,7 @@ static void __devinit e1000_check_copper_options(struct e1000_adapter *adapter) "parameter ignored\n"); adapter->hw.autoneg_advertised = AUTONEG_ADV_DEFAULT; } else { /* Autoneg */ - struct e1000_opt_list an_list[] = + static const struct e1000_opt_list an_list[] = #define AA "AutoNeg advertising " {{ 0x01, AA "10/HD" }, { 0x02, AA "10/FD" }, @@ -671,7 +680,7 @@ static void __devinit e1000_check_copper_options(struct e1000_adapter *adapter) { 0x2e, AA "1000/FD, 100/FD, 100/HD, 10/FD" }, { 0x2f, AA "1000/FD, 100/FD, 100/HD, 10/FD, 10/HD" }}; - struct e1000_option opt = { + opt = (struct e1000_option) { .type = list_option, .name = "AutoNeg", .err = "parameter ignored", -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/