Messages in this thread |  | | Subject | Re: /proc/sys/kernel/shmmax does not increase shared ram | From | Christoph Rohland <> | Date | 31 Aug 2000 18:27:06 +0200 |
| |
Michael Bielicki <Michael.Bielicki@Parmastocks.com> writes:
> Hi, > I found this effect on both test6 and test7 that if I type: > > echo 128000000 > /proc/sys/kernel/shmmax > it has no real effect on the amount of shared memory.
# uname -a Linux ls3016 2.4.0-test7 #1 SMP Thu Aug 31 15:12:24 CEST 2000 i686 unknown # ipcs -ml
------ Shared Memory Limits -------- max number of segments = 4096 max seg size (kbytes) = 1048576 max total shared memory (kbytes) = 12240000 min seg size (bytes) = 0
# cat /proc/sys/kernel/shmmax 1073741824 # ./ipctst 1 1073741824 1 0 100 using 1 segs of size 1073741824 (1 iterations) # ./ipctst 1 1073741825 1 0 100 using 1 segs of size 1073741825 (1 iterations) shmget (0x1): Invalid argument
So this seems to work.
> besides, what does the output of df on /dev/shm show me ? the amount > of max shared mem in bytes or kbytes like the other fs ?
Yes, it does. You can increase the maximum overall size with mount option nr_blocks (in 4K blocks on ia32) and the maximum number of objects with nr_inodes.
from ipc/shm.c:
* There are the following mount options: * - nr_blocks (^= shmall) is the number of blocks of size PAGE_SIZE * we are allowed to allocate * - nr_inodes (^= shmmni) is the number of files we are allowed to * allocate * - mode is the mode for the root directory (default S_IRWXUGO | S_ISVTX)
Greetings Christoph - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
|  |