Re: process to inspect generated assembly of a function

n Fri, 06 Jun 2014, valdis.kletni...@vt.edu wrote: On Fri, 06 Jun 2014 12:23:35 -0400, Andev said: I am trying to inspect the generated assembly for a function in the kernel. Are there any documents explaining how to do this? I want to see how it changes when I change the function body.

Re: unlikely compiler flag propagation

On Wed, 18 Feb 2015, Greg KH wrote: On Wed, Feb 18, 2015 at 07:09:47PM +0100, Matthias Brugger wrote: Hi all, I have a question about the unlikely compiler flag. When a called function is only returns an error with the unlikely flag set, should I set the unlikely compiler flag for the

Re: unlikely compiler flag propagation

On Wed, 18 Feb 2015, valdis.kletni...@vt.edu wrote: On Wed, 18 Feb 2015 19:38:01 +0100, Nicholas Mc Guire said: On Wed, 18 Feb 2015, Greg KH wrote: interesting - would you have a reference to some talk/paper/data/... ? Test for yourself :) config PROFILE_ANNOTATED_BRANCHES

Re: spinlock variable protection

On Fri, 30 Jan 2015, Matwey V. Kornilov wrote: 2015-01-30 16:52 GMT+03:00 buyitian buyit...@gmail.com: Please check the assembly code to double confirm the GCC behavior. Why will GCC change the order as what you mentioned? Only assembly code can tell you. It does not change at the

Re: confusing code....whats the point of this construct ?

On Wed, 11 Mar 2015, Bj??rn Mork wrote: valdis.kletni...@vt.edu writes: On Wed, 11 Mar 2015 15:17:44 +0100, Nicholas Mc Guire said: So the wait_event_timeout condition here ends up being (empty || skip) but what is the point of puting this code into the parameter list

Re: confusing code....whats the point of this construct ?

On Wed, 11 Mar 2015, Jeff Haran wrote: -Original Message- From: kernelnewbies-boun...@kernelnewbies.org [mailto:kernelnewbies-boun...@kernelnewbies.org] On Behalf Of valdis.kletni...@vt.edu Sent: Wednesday, March 11, 2015 10:00 AM To: Nicholas Mc Guire Cc: Bj??rn Mork

Re: CHECK: Alignment should match open parenthesis

On Fri, 13 Mar 2015, Jeff Haran wrote: -Original Message- From: Nicholas Mc Guire [mailto:der.h...@hofr.at] Sent: Friday, March 13, 2015 9:59 AM To: Jeff Haran Cc: Daniel Baluta; kernelnewbies@kernelnewbies.org; palik imre Subject: Re: CHECK: Alignment should match open parenthesis

Re: CHECK: Alignment should match open parenthesis

On Fri, 13 Mar 2015, palik imre wrote: Sorry for the silly question, but I have some issues with this checkpatch.pl warning. I mean Documentation/CodingStyle says: Outside of comments, documentation and except in Kconfig, spaces are never used for indentation, and the above example is

Re: CHECK: Alignment should match open parenthesis

On Fri, 13 Mar 2015, Daniel Baluta wrote: On Fri, Mar 13, 2015 at 3:47 PM, Nicholas Mc Guire der.h...@hofr.at wrote: On Fri, 13 Mar 2015, Nicholas Mc Guire wrote: On Fri, 13 Mar 2015, palik imre wrote: On Friday, 13 March 2015, 13:43, Nicholas Mc Guire der.h...@hofr.at wrote

Re: CHECK: Alignment should match open parenthesis

On Fri, 13 Mar 2015, Jeff Haran wrote: -Original Message- From: kernelnewbies-boun...@kernelnewbies.org [mailto:kernelnewbies-boun...@kernelnewbies.org] On Behalf Of Nicholas Mc Guire Sent: Friday, March 13, 2015 8:33 AM To: Daniel Baluta Cc: kernelnewbies@kernelnewbies.org

Re: confusing code....whats the point of this construct ?

On Wed, 11 Mar 2015, valdis.kletni...@vt.edu wrote: On Wed, 11 Mar 2015 15:17:44 +0100, Nicholas Mc Guire said: So the wait_event_timeout condition here ends up being (empty || skip) but what is the point of puting this code into the parameter list of wait_event_timeout() ? Would

confusing code....whats the point of this construct ?

HI ! Trying to understand the intent of this code construct drivers/net/wireless/ath/ath10k/mac.c:ath10k_flush() snip ret = wait_event_timeout(ar-htt.empty_tx_wq, ({ bool empty; spin_lock_bh(ar-htt.tx_lock); empty

set_current_state() use in loops confusion

Hi ! Noticed that in a number of cases - often while(!kthread_should_stop()){ loops the call to set_current_state(...) is inside the loop - but e.g. in the below case why would that be needed ? schedule() is not changing the state visibly for the loop - so what is the point of setting the

Re: set_current_state() use in loops confusion

On Sun, 07 Jun 2015, Nicholas Mc Guire wrote: Hi ! Noticed that in a number of cases - often while(!kthread_should_stop()){ loops the call to set_current_state(...) is inside the loop - but e.g. in the below case why would that be needed ? schedule() is not changing the state visibly

Re: Why Completely Fair Scheduler(CFS) using Red-Black tree instead of Min-heap?

On Sat, Oct 17, 2015 at 11:55:29PM +0530, venu gangireddy wrote: > Hi, > > Currently, I am learning about CFS scheduler in linux, and I want to know > reason about the data structure chooses in CFS implementation. > > CFS scheduler picks next process based on minimum virtual time and to get >

Re: Best tests to measure Kernel Performance

On Wed, Dec 02, 2015 at 04:36:50PM -0800, Greg KH wrote: > On Wed, Dec 02, 2015 at 05:50:30PM -0600, Victor Rodriguez wrote: > > On Tue, Dec 1, 2015 at 7:32 PM, Greg KH wrote: > > > On Tue, Dec 01, 2015 at 06:45:51PM -0600, Victor Rodriguez wrote: > > >> Hi > > >> > >

Re: How to correctly decode fun+X/Y

On Thu, Dec 03, 2015 at 09:14:38PM +0300, Matwey V. Kornilov wrote: > Hello, > > I have the following stack trace: > > [ 1351.381696] a.out S c0afb050 0 1676 1658 0x > [ 1351.387048] [] (__schedule) from [] > (schedule+0x58/0xcc) > [ 1351.392436] [] (schedule) from [] >

Coding style quesion

HI ! Stumbled across the somewhat inconsistent treatement of functions returning ERR_PTR() in the kernel with respect to coding style, while trying to write some static code checks. The two forms which seem comon are: if (PTR_ERR(var) == -EINVAL) { and if

Re: how to use wait_event_interruptible_timeout with less than 1 jiffie timeout?

On Wed, Jan 20, 2016 at 06:57:27PM +0530, Anupam Kapoor wrote: > > >>>>> [2016-01-20T13:55:54+0530]: "Nicholas Mc Guire" (Nicholas): > ,[ Nicholas ] > | that would still have the same limitation with resepct to time granuarlity > | and as Documentati

Re: how to use wait_event_interruptible_timeout with less than 1 jiffie timeout?

On Wed, Jan 20, 2016 at 11:50:24AM +0530, Anupam Kapoor wrote: > > > [2016-01-20T01:21:18+0530]: "Daniel." (Daniel): > ,[ Daniel ] > | I have some code that convert an timeout comming from userspace (in > | ms) to jiffies prior passing to wait_event_interrupitible_timeout(). > | The code

Re: remote system call

On Sat, Mar 05, 2016 at 04:58:07PM -0500, valdis.kletni...@vt.edu wrote: > On Sat, 05 Mar 2016 15:58:13 +0530, Nitin Varyani said: > > Codes are huge and documentation is negligible. How can I separate whay I > > want to achieve from that big code? > > Why do you think that's possible? > > It's

Re: inline keyword

On Fri, Mar 11, 2016 at 10:47:27AM -0800, Greg KH wrote: > On Fri, Mar 11, 2016 at 01:39:53PM -0500, Wenda Ni wrote: > > Hi all, > > > > For a function that is defined static but without an explicit "inline" > > keyword, > > is there a possibility that compiler will optimize it to be a static

Re: Is it possible to turn off the gcc optimization when compiling kernel?

On Tue, Mar 22, 2016 at 07:24:38PM +0800, Hao Lee wrote: > On Mon, Mar 21, 2016 at 5:51 PM, Nicholas Mc Guire <der.h...@hofr.at> wrote: > > You can not turn it off in all functions as some need particluar > > optimization flags to comile at all, but you can pass > > ind

Re: Is it possible to turn off the gcc optimization when compiling kernel?

On Sun, Mar 20, 2016 at 02:46:41PM +0800, Hao Lee wrote: > Hi, > When I am debugging the linux kernel, I find that the execution > sequence of some code is very strange. I think I need to turn off gcc > optimization by changing "-O2" to "-O0". But I encounter many errors. > So, I want to know is

Re: single, comprehensive kernel data types document?

On Fri, Apr 15, 2016 at 05:27:24AM -0700, Greg KH wrote: > On Fri, Apr 15, 2016 at 08:04:53AM -0400, Robert P. J. Day wrote: > > > > is there a single, decent online doc that explains the proper data > > types (int16_t, int32_t and so on) to use in kernel code? > > First off, never use int16_t

Determining patch impact on a specific config

Hi ! For a given patch I would like to find out if it impacts a given configuration or not. Now of course one could compile the kernel for the configuration prior to the patch, then apply the patch and recompile to find out if there is an impact but I would be looking for some smarter

Re: Determining patch impact on a specific config

On Wed, Aug 17, 2016 at 03:52:16PM +0200, Greg KH wrote: > On Wed, Aug 17, 2016 at 03:25:44PM +0200, Greg KH wrote: > > On Wed, Aug 17, 2016 at 12:39:39PM +, Nicholas Mc Guire wrote: > > > > > > Hi ! > > > > > > For a given patch I would

Re: Determining patch impact on a specific config

On Wed, Aug 17, 2016 at 04:17:19PM +0200, Greg KH wrote: > On Wed, Aug 17, 2016 at 02:01:28PM +0000, Nicholas Mc Guire wrote: > > On Wed, Aug 17, 2016 at 03:52:16PM +0200, Greg KH wrote: > > > On Wed, Aug 17, 2016 at 03:25:44PM +0200, Greg KH wrote: > > > > On Wed, Au

Re: Determining patch impact on a specific config

On Wed, Aug 17, 2016 at 05:39:27PM +0200, Greg KH wrote: > On Wed, Aug 17, 2016 at 02:49:22PM +0000, Nicholas Mc Guire wrote: > > On Wed, Aug 17, 2016 at 04:17:19PM +0200, Greg KH wrote: > > > On Wed, Aug 17, 2016 at 02:01:28PM +, Nicholas Mc Guire wrote: > > > >

Re: Determining patch impact on a specific config

On Wed, Aug 17, 2016 at 07:34:02PM +0200, Greg KH wrote: > On Wed, Aug 17, 2016 at 04:50:30PM +0000, Nicholas Mc Guire wrote: > > > But you aren't comparing that to the number of changes that are > > > happening in a "real" release. If you do that, you will see

Re: udelay vs usleep_range

> > But looking into the code on line 634 where I found the udelay(33), I > have the impression that this is a false positive, something your > checkpatch didn't catch properly. That call is inside a function named > nvec_interrupt(), and the line: > > err = devm_request_irq(>dev,

Re: udelay vs usleep_range

On Sun, Sep 11, 2016 at 06:37:40PM +0200, Peter Senna Tschudin wrote: > Hi Gargi, > > On Sun, Sep 11, 2016 at 5:58 PM, Gargi Sharma wrote: > > Hi all, > > > > I ran the checkpatch script over drivers/staging/nvec.c and got the > > following warning > > > > udelay(33); > > >

Re: udelay vs usleep_range

On Sun, Sep 11, 2016 at 09:28:29PM +0530, Gargi Sharma wrote: > Hi all, > > I ran the checkpatch script over drivers/staging/nvec.c and got the > following warning > > udelay(33); > > CHECK: usleep_range is preferred over udelay; see > Documentation/timers/timers-howto.txt > > I checked out

Re: if/else block default coding style question

On Sat, Oct 08, 2016 at 11:10:10AM -0400, Robert P. J. Day wrote: > On Sat, 8 Oct 2016, valdis.kletni...@vt.edu wrote: > > > On Sat, 08 Oct 2016 10:40:37 -0000, Nicholas Mc Guire said: > > > > >} else if (rtlpcipriv->bt_coexist.bt_service == BT_PAN) { > >

Re: if/else block default coding style question

On Sat, Oct 08, 2016 at 10:58:41AM -0400, valdis.kletni...@vt.edu wrote: > On Sat, 08 Oct 2016 10:40:37 -0000, Nicholas Mc Guire said: > > >} else if (rtlpcipriv->bt_coexist.bt_service == BT_PAN) { > >rtl_write_byte(rtlpriv, REG_GPIO_MUXCFG, tmp

if/else block default coding style question

Hi ! There are quite a few places (roughly 90) in the kernel where an if/else if/else block repeats the last "case" presumably as default e.g. drivers/net/wireless/realtek/rtlwifi/rtl8192c/dm_common.c if ((rtlpcipriv->bt_coexist.bt_service == BT_BUSY) &&

Re: Data Type used in kernel .

On Fri, Dec 23, 2016 at 06:33:28AM -0500, Pasquier, Thomas wrote: > Hello Wasim, > > On Fri, Dec 23, 2016 at 6:20 AM, Wasim Akram > wrote: > > > Hi , > > > > I have seen "bool" data type is used in linux kernel code . Can we > > get documentation on data type used in

Re: Data Type used in kernel .

On Fri, Dec 23, 2016 at 07:01:37PM +0100, Greg KH wrote: > On Fri, Dec 23, 2016 at 11:52:33AM +0000, Nicholas Mc Guire wrote: > > On Fri, Dec 23, 2016 at 06:33:28AM -0500, Pasquier, Thomas wrote: > > > Hello Wasim, > > > > > > On Fri, Dec 23, 2016 a

Re: where's the definition of trace_kfree_skb?

On Tue, Mar 28, 2017 at 04:15:57PM +0800, Shiyao Ma wrote: > Hi, > I saw this function invocation, > trace_kfree_skb(skb, __builtin_return_address(0)); > > so I grepped the source for "trace_kfree_skb", but I found no where it's > defined. > > Where's the definition for it? > that is a

Re: How to report bugs for release candidates?

On Sun, Mar 26, 2017 at 10:15:17AM +0200, Greg KH wrote: > On Sat, Mar 25, 2017 at 11:16:56AM +0100, Martin Kletzander wrote: > > Hi everyone, > > > > I was usually using Bugzilla when I wanted to report something, but what > > if, for example, I can't boot 4.11-rc3? Is bugzilla fast enough for

Re: [0] vs array

On Thu, Mar 30, 2017 at 09:04:35AM -0400, Ruben Safir wrote: > On 03/29/2017 08:30 PM, Tobin C. Harding wrote: > > Does the kernel community have a preference when using the address of > > the first element of an an array? > > > > 1. addr = [0] > > 2. addr = array; > > > > $ grep '\&.*\[0\]' |

Re: How to get patches from e-mail client?

On Mon, Apr 17, 2017 at 08:02:32AM +, Amit Kumar wrote: > On Mon, Apr 17, 2017 at 03:52:42PM +0800, Rock Lee wrote: > > Hi: > > If I want to get a patch and use "git am" to merge it into my project, > > how can I do? I mean I can copy and paste a patch from my e-mail > > client, but it is too

Re: diff

On Mon, Mar 13, 2017 at 05:57:14PM +1100, Tobin C. Harding wrote: > On occasions diff output does not render the same as it does when > editing a file. For example, while removing checkpatch tab warning > the following diff was generated > > -#define KS_WLAN_SET_WPS_ENABLE

Re: coccinelle

On Tue, Mar 14, 2017 at 06:21:06PM +1100, Tobin C. Harding wrote: > Attempting to do transform using Coccinelle > > if (foo != 0) { >... > > -> > > if (foo) { >... > > Coccinelle script attempt does not work > > @@ expression x; @@ > ( > - x != 0 > + x > ) I think you do not need the

Re: [PATCH] staging: vboxvideo: Update driver to use drm_dev_register.

On Sat, Jun 02, 2018 at 08:41:44AM -0300, Fabio Rafael da Rosa wrote: > The use of load and unload hooks is deprecated. DRM drivers should > use drm_dev_alloc|drm_dev_init and drm_dev_register for initialization > and publishing. > > Signed-off-by: Fabio Rafael da Rosa Reviewed-

Re: first patch question

On Tue, Aug 07, 2018 at 12:15:04AM -0400, Greg Gallagher wrote: > Hi, >I creating my first patch to the kernel. I followed the > instruction on the newbies wiki and everything went smoothly. I got > feedback from the maintainer to fix all the alignment issues in the > file instead of just

Re: System call vs POSIX call

On Thu, Aug 16, 2018 at 09:51:05PM +0530, Subhashini Rao Beerisetty wrote: > Hi All, > > I'm trying to get the difference between system call and POSIX call. System > calls are user mode API's (open(), close(), ioctl(),...) gets the kernel > service via software interrupt. What about POSIX calls

Re: System call vs POSIX call

On Thu, Aug 16, 2018 at 03:44:49PM -0400, valdis.kletni...@vt.edu wrote: > On Thu, 16 Aug 2018 16:29:29 -0000, Nicholas Mc Guire said: > > > Note that you can do system calls directly with system() but that is > > generaly not how you do it - you to through the glibc calls

Re: first patch question

On Thu, Aug 09, 2018 at 01:19:53PM -0400, greg gallagher wrote: > > > On 2018-08-07 12:47 AM, Nicholas Mc Guire wrote: > >On Tue, Aug 07, 2018 at 12:15:04AM -0400, Greg Gallagher wrote: > >>Hi, > >>I creating my first patch to the kernel. I followed the &g

Re: regarding const variables/structures

On Wed, Sep 12, 2018 at 11:50:35AM +0530, inventsekar wrote: > Hi All... > One curious question.. > > Linux Foundation tweeted this - > Meet Bhumika Goyal, age 22, from India. She has had more 340 patches > accepted into the Linux kernel, which helped her land one of our two Linux > Kernel Guru

Re: [PATCH] sched/fair: Change sched_feat(x) in !CONFIG_SCHED_DEBUG case

ted with gcc 7.3.1 and clang 6.0.0 on x86_64, comparing resulting > binaries with diff. > Applicable to all modern compilers and architectures > > Signed-off-by: Philipp Klocke <phil_...@gmx.de> > Suggested-by: Lukas Bulwahn <lukas.bulw...@gmail.com> Reviewed-by: Nicholas Mc Guire <

Re: Quick interview with any community members

On Tue, Oct 30, 2018 at 05:34:38PM -0400, Alex Frederiksen wrote: > Hey guys. > > I decided to do a college paper on the Linux discourse community, > particularly on how a person navigates between groups and gains "authority" > within the community. If ya guys could answer some of my questions,

RO data

HI ! devm_kstrdup_const() will check if the pointer passed in is in the RO data section with is_kernel_rodata() But this is simply a check for address range - so how can one find out at code level reliably what will be in that RO data - or is that in principle not possible ? The

Re: regarding const variables/structures

On Thu, Sep 13, 2018 at 09:12:32AM +0530, inventsekar wrote: > >>> A brute force grep in the kernel shows that there are 130493 " const " > in there > Hi Hofrat, > 1. may i know the command to do this above grep please.. $ grep -cre " const " * | more will give you the " const " count per file -

building .lst files for a subdirectory

Hi ! Probably I´m just overlooking something obvious but trying to build .lst files in directories that have no Makefile is causing problems. For "normal" files its simply $ make path/file.lst but that seems to assume that there always is a Makefile in each directory. For some drivers

Re: Is there a "build everything" kernel configuration?

On Fri, Apr 12, 2019 at 10:40:35PM -0700, Jefferson Carpenter wrote: > Supposing I want to make a change to the Kernel code and make sure that it > all builds (i.e. that I did not cause any compile errors under any > configuration), what's best way to do that?  Can I just take the default >

Re: How to generate Fixes: ("") things

On Thu, May 09, 2019 at 01:41:44PM +0200, Greg KH wrote: > On Thu, May 09, 2019 at 12:38:01PM +0200, Nicholas Mc Guire wrote: > > On Thu, May 09, 2019 at 06:28:39PM +0800, wuzhouhui wrote: > > > Hi, > > > > > > Stupid question, maybe. But I just could find

Re: How to generate Fixes: ("") things

On Thu, May 09, 2019 at 06:28:39PM +0800, wuzhouhui wrote: > Hi, > > Stupid question, maybe. But I just could find the answer vi Bing or Google. > > How to generate > Fixes: ("") > E.g. > Fixes: 298a32b13208 ("kmemleak: powerpc: skip scanning holes in the .bss > section") > > Or they

.lst files with no Makefile in the subdirectory ?

HI ! I'm trying to generate the .lst files to check the impact of a patch but in the specific directory there is no Makefile only in the parrent directory. specifically I'm trying to build the security/selinux/ss/ebitmap.lst hofrat@debian:~/linux-next$ make security/selinux/ss/ebitmap.lst

Fixes tag confusion

Hi ! Looking at some of the fixes tags in linux-stable e.g. commit 27d231c0c63b -> :pnfs_alloc_ds_commits_list:fs/nfs/pnfs_nfs.c Fixes: a9901899b649 inspecting the history of this function shows linux-stable$ git log -L:pnfs_alloc_ds_commits_list:fs/nfs/pnfs_nfs.c | grep "^commit "

Re: Fixes tag confusion

On Mon, Apr 13, 2020 at 09:46:41PM +0200, Valentin Vidi?? wrote: > On Mon, Apr 13, 2020 at 07:15:17PM +0200, Nicholas Mc Guire wrote: > > linux-stable$ git log -L:get_fs_type:fs/filesystems.c | grep "^commit " > > commit d8e9650dff48055057253ca309

Re: How is the size of init ram disk determined when initramfs is used?

On Sun, Jan 01, 2023 at 06:32:55PM +0100, Bernd Petrovitsch wrote: > Hi all! > > On 07/10/2022 04:32, Chan Kim wrote: > [...] > >I'm using initramfs.cpio.gz for initial file system image. > >I embed it in the kernel Image file. > >After linux boots, when I'm in the shell, I can create files. >