On Mon, Jul 25, 2011 at 9:41 PM, Manish Katiyar [off-list ref] wrote:

On Mon, Jul 25, 2011 at 9:29 PM, Abhijit Pawar [off-list ref] wrote:

quoted

Hi Dave,
On 07/25/2011 09:20 PM, Dave Hylands wrote:

quoted

Hi Abhijit,

On Mon, Jul 25, 2011 at 6:35 AM, Abhijit Pawar[off-list ref] ?wrote:

quoted

On 07/25/2011 05:29 PM, Naveen Kumar wrote:

You can use command ulimit -a, there you can check the limit for a process.

Thanks,
Naveen

Ulimit gives 1024 as open file limit. In struct task_struct it has a member
called struct files_struct *files;

I tried checking for this member and the limit however I am ?not able to
decide correctly why the limit is 1024.
? Also, is there any distinction between 32 bit and 64 bit systems for this
limit?

My 64-bit system reports 1024 as well.

I have no troubles compiling kernels.

Thanks. Yes, on my 64 bit Fedora 15 I get same value as yours.

What I am interested in is knowing why the limit is on 1024 File
Descriptors? That means 1024 Inodes. AFAIK there isnt anything written
in filesystem code which will put this limit of 1024 inodes for a process.
This means its very specific to the process.
Unfortunately I am know having details on the process front. Is there
anything which you or anyone aware in process area because of which this
limit is there?

man getdtablesize

and if you trace the kernel code, it comes from the limits of the init
task, which is hard coded during creation. You can get/set these
values using getrlimit/setrlimit.


include/linux/init_task.h
33 #define INIT_SIGNALS(sig) {                                             \
.................
.................
 41         .rlim           = INIT_RLIMITS,
..............

include/asm-generic/resource.h
 72 #define INIT_RLIMITS                                                    \
 73 {                                                                       \
 74         [RLIMIT_CPU]            = {  RLIM_INFINITY,  RLIM_INFINITY },   \
 75         [RLIMIT_FSIZE]          = {  RLIM_INFINITY,  RLIM_INFINITY },   \
 76         [RLIMIT_DATA]           = {  RLIM_INFINITY,  RLIM_INFINITY },   \
 77         [RLIMIT_STACK]          = {       _STK_LIM,   _STK_LIM_MAX },   \
 78         [RLIMIT_CORE]           = {              0,  RLIM_INFINITY },   \
 79         [RLIMIT_RSS]            = {  RLIM_INFINITY,  RLIM_INFINITY },   \
 80         [RLIMIT_NPROC]          = {              0,              0 },   \
 81         [RLIMIT_NOFILE]         = {   INR_OPEN_CUR,   INR_OPEN_MAX },   \
...............
..............

include/linux/fs.h
25 #undef NR_OPEN
 26 #define INR_OPEN_CUR 1024       /* Initial setting for nfile rlimits */
 27 #define INR_OPEN_MAX 4096       /* Hard limit for nfile rlimits */


HTH
-- 
Thanks -
Manish