user/sven/linux.git/Documentation, branch v3.0.51

x86: Remove the ancient and deprecated disable_hlt() and enable_hlt() facility

2012-11-05T08:44:26Z

commit f6365201d8a21fb347260f89d6e9b3e718d63c70 upstream. The X86_32-only disable_hlt/enable_hlt mechanism was used by the 32-bit floppy driver. Its effect was to replace the use of the HLT instruction inside default_idle() with cpu_relax() - essentially it turned off the use of HLT. This workaround was commented in the code as: "disable hlt during certain critical i/o operations" "This halt magic was a workaround for ancient floppy DMA wreckage. It should be safe to remove." H. Peter Anvin additionally adds: "To the best of my knowledge, no-hlt only existed because of flaky power distributions on 386/486 systems which were sold to run DOS. Since DOS did no power management of any kind, including HLT, the power draw was fairly uniform; when exposed to the much hhigher noise levels you got when Linux used HLT caused some of these systems to fail. They were by far in the minority even back then." Alan Cox further says: "Also for the Cyrix 5510 which tended to go castors up if a HLT occurred during a DMA cycle and on a few other boxes HLT during DMA tended to go astray. Do we care ? I doubt it. The 5510 was pretty obscure, the 5520 fixed it, the 5530 is probably the oldest still in any kind of use." So, let's finally drop this. Signed-off-by: Len Brown Signed-off-by: Josh Boyer Signed-off-by: Andrew Morton Acked-by: "H. Peter Anvin" Acked-by: Alan Cox Cc: Stephen Hemminger Link: http://lkml.kernel.org/n/tip-3rhk9bzf0x9rljkv488tloib@git.kernel.org [ If anyone cares then alternative instruction patching could be used to replace HLT with a one-byte NOP instruction. Much simpler. ] Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

x86, random: Verify RDRAND functionality and allow it to be disabled

2012-10-21T16:17:12Z

commit 49d859d78c5aeb998b6936fcb5f288f78d713489 upstream. If the CPU declares that RDRAND is available, go through a guranteed reseed sequence, and make sure that it is actually working (producing data.) If it does not, disable the CPU feature flag. Allow RDRAND to be disabled on the command line (as opposed to at compile time) for a user who has special requirements with regards to random numbers. Signed-off-by: H. Peter Anvin Cc: Matt Mackall Cc: Herbert Xu Cc: "Theodore Ts'o" Signed-off-by: Greg Kroah-Hartman

stable: update references to older 2.6 versions for 3.x

2012-08-09T15:27:36Z

commit 2584f5212d97b664be250ad5700a2d0fee31a10d upstream. Also add information on where the respective trees are. Signed-off-by: Paul Gortmaker Acked-by: Rob Landley Signed-off-by: Greg Kroah-Hartman

mm: change isolate mode from #define to bitwise type

2012-08-01T19:27:16Z

commit 4356f21d09283dc6d39a6f7287a65ddab61e2808 upstream. Stable note: Not tracked in Bugzilla. This patch makes later patches easier to apply but has no other impact. Change ISOLATE_XXX macro with bitwise isolate_mode_t type. Normally, macro isn't recommended as it's type-unsafe and making debugging harder as symbol cannot be passed throught to the debugger. Quote from Johannes " Hmm, it would probably be cleaner to fully convert the isolation mode into independent flags. INACTIVE, ACTIVE, BOTH is currently a tri-state among flags, which is a bit ugly." This patch moves isolate mode from swap.h to mmzone.h by memcontrol.h Signed-off-by: Minchan Kim Cc: Johannes Weiner Cc: KAMEZAWA Hiroyuki Cc: KOSAKI Motohiro Cc: Mel Gorman Cc: Rik van Riel Cc: Michal Hocko Cc: Andrea Arcangeli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Mel Gorman Signed-off-by: Greg Kroah-Hartman

stable: Allow merging of backports for serious user-visible performance issues

2012-07-16T15:47:48Z

commit eb3979f64d25120d60b9e761a4c58f70b1a02f86 upstream. Distribution kernel maintainers routinely backport fixes for users that were deemed important but not "something critical" as defined by the rules. To users of these kernels they are very serious and failing to fix them reduces the value of -stable. The problem is that the patches fixing these issues are often subtle and prone to regressions in other ways and need greater care and attention. To combat this, these "serious" backports should have a higher barrier to entry. This patch relaxes the rules to allow a distribution maintainer to merge to -stable a backported patch or small series that fixes a "serious" user-visible performance issue. They should include additional information on the user-visible bug affected and a link to the bugzilla entry if available. The same rules about the patch being already in mainline still apply. Signed-off-by: Mel Gorman Signed-off-by: Greg Kroah-Hartman

docs: update HOWTO for 2.6.x -> 3.x versioning

2012-06-01T07:12:55Z

commit 591bfc6bf9e5e25e464fd4c87d64afd5135667c4 upstream. The HOWTO document needed updating for the new kernel versioning. The git URI for -next was updated as well. Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman

tcp: change tcp_adv_win_scale and tcp_rmem[2]

2012-05-21T16:40:00Z

[ Upstream commit b49960a05e32121d29316cfdf653894b88ac9190 ] tcp_adv_win_scale default value is 2, meaning we expect a good citizen skb to have skb->len / skb->truesize ratio of 75% (3/4) In 2.6 kernels we (mis)accounted for typical MSS=1460 frame : 1536 + 64 + 256 = 1856 'estimated truesize', and 1856 * 3/4 = 1392. So these skbs were considered as not bloated. With recent truesize fixes, a typical MSS=1460 frame truesize is now the more precise : 2048 + 256 = 2304. But 2304 * 3/4 = 1728. So these skb are not good citizen anymore, because 1460 < 1728 (GRO can escape this problem because it build skbs with a too low truesize.) This also means tcp advertises a too optimistic window for a given allocated rcvspace : When receiving frames, sk_rmem_alloc can hit sk_rcvbuf limit and we call tcp_prune_queue()/tcp_collapse() too often, especially when application is slow to drain its receive queue or in case of losses (netperf is fast, scp is slow). This is a major latency source. We should adjust the len/truesize ratio to 50% instead of 75% This patch : 1) changes tcp_adv_win_scale default to 1 instead of 2 2) increase tcp_rmem[2] limit from 4MB to 6MB to take into account better truesize tracking and to allow autotuning tcp receive window to reach same value than before. Note that same amount of kernel memory is consumed compared to 2.6 kernels. Signed-off-by: Eric Dumazet Cc: Neal Cardwell Cc: Tom Herbert Cc: Yuchung Cheng Acked-by: Neal Cardwell Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

hwmon: (jc42) Add support for AT30TS00, TS3000GB2, TSE2002GB2, and MCP9804

2012-03-12T17:33:00Z

commit 1bd612a25855f4cc9345052b53d7da697dba6358 upstream. Also update IDT datasheet locations. Signed-off-by: Guenter Roeck Acked-by: Jean Delvare Signed-off-by: Greg Kroah-Hartman

hwmon: (jc42) Add support for ST Microelectronics STTS2002 and STTS3000

2012-03-12T17:33:00Z

commit 4de86126a712ba83fa038d277c8282f7ed466a4b upstream. These are fully compatible with Jedec JC 42.4 as far as I can see. Signed-off-by: Jean Delvare Cc: Guenter Roeck Signed-off-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman

USB: update documentation for usbmon

2012-01-12T19:35:06Z

commit d8cae98cddd286e38db1724dda1b0e7b467f9237 upstream. The documentation for usbmon is out of date; the usbfs "devices" file now exists in /sys/kernel/debug/usb rather than /proc/bus/usb. This patch (as1505) updates the documentation accordingly, and also mentions that the necessary information can be found by running lsusb. Signed-off-by: Alan Stern CC: Pete Zaitcev Signed-off-by: Greg Kroah-Hartman