From: Hugh Dickins <hughd@google.com>
To: naveen yadav <yad.naveen@gmail.com>
Cc: kernelnewbies <Kernelnewbies@kernelnewbies.org>,
linux-kernel@vger.kernel.org
Subject: Re: shmem info issue
Date: Fri, 12 Jul 2013 15:58:38 -0700 (PDT) [thread overview]
Message-ID: <alpine.LNX.2.00.1307121529190.3315@eggly.anvils> (raw)
In-Reply-To: <CAJ8eaTw9o+ZBAzR+1qe-5XEpfZzv-6DJ_EHK_BF_32-va-KL+g@mail.gmail.com>
On Fri, 12 Jul 2013, naveen yadav wrote:
> Hi All
>
> I am working on tmpfs. During code analysis I found shmem driver
> register itself as tmpfs .
>
> cat /proc/meminfo Shmem field read NR_SHMEM enum filed and shows used
> memory in tmpfs
>
>
> [root@localhost linux-3.8.2]# cat /proc/meminfo | grep -r Shmem
> Shmem: 704 kB
> [root@localhost linux-3.8.2]#
>
> include/linux/mmzone.h
> enum zone_stat_item {
> -----cut here-------
> NR_SHMEM, /* shmem pages (included tmpfs/GEM pages
> -----cut here
> }
>
> I have the following query
> 1-> cat /proc/meminfo | grep -r Shmem show only the used tmpfs memory
> or it show used tmpfs memory + mata data also (because I found Shmem
> is bit larger then tempfs used memory )
"Shmem" includes only data, not metadata, nor memory currently swapped
out. But it includes tmpfs memory, SysV shared memory (from ipc/shm.c),
POSIX shared memory (under /dev/shm), and shared anonymous mappings
(from mmap of /dev/zero with MAP_SHARED: see call to shmem_zero_setup()
from drivers/char/mem.c): whatever allocates pages through mm/shmem.c.
> 2-> as per the developer comments NR_SHMEM included tmpfs and GEM
> pages whct is Gem pages
Ah yes, and the Graphics Execution Manager uses shmem for objects shared
with the GPU: see use of shmem_read_mapping_page*() in drivers/gpu/drm/.
> 3-> is my above code analysis is correct?
I think so.
Hugh
WARNING: multiple messages have this Message-ID (diff)
From: hughd@google.com (Hugh Dickins)
To: kernelnewbies@lists.kernelnewbies.org
Subject: shmem info issue
Date: Fri, 12 Jul 2013 15:58:38 -0700 (PDT) [thread overview]
Message-ID: <alpine.LNX.2.00.1307121529190.3315@eggly.anvils> (raw)
In-Reply-To: <CAJ8eaTw9o+ZBAzR+1qe-5XEpfZzv-6DJ_EHK_BF_32-va-KL+g@mail.gmail.com>
On Fri, 12 Jul 2013, naveen yadav wrote:
> Hi All
>
> I am working on tmpfs. During code analysis I found shmem driver
> register itself as tmpfs .
>
> cat /proc/meminfo Shmem field read NR_SHMEM enum filed and shows used
> memory in tmpfs
>
>
> [root at localhost linux-3.8.2]# cat /proc/meminfo | grep -r Shmem
> Shmem: 704 kB
> [root at localhost linux-3.8.2]#
>
> include/linux/mmzone.h
> enum zone_stat_item {
> -----cut here-------
> NR_SHMEM, /* shmem pages (included tmpfs/GEM pages
> -----cut here
> }
>
> I have the following query
> 1-> cat /proc/meminfo | grep -r Shmem show only the used tmpfs memory
> or it show used tmpfs memory + mata data also (because I found Shmem
> is bit larger then tempfs used memory )
"Shmem" includes only data, not metadata, nor memory currently swapped
out. But it includes tmpfs memory, SysV shared memory (from ipc/shm.c),
POSIX shared memory (under /dev/shm), and shared anonymous mappings
(from mmap of /dev/zero with MAP_SHARED: see call to shmem_zero_setup()
from drivers/char/mem.c): whatever allocates pages through mm/shmem.c.
> 2-> as per the developer comments NR_SHMEM included tmpfs and GEM
> pages whct is Gem pages
Ah yes, and the Graphics Execution Manager uses shmem for objects shared
with the GPU: see use of shmem_read_mapping_page*() in drivers/gpu/drm/.
> 3-> is my above code analysis is correct?
I think so.
Hugh
next prev parent reply other threads:[~2013-07-12 22:58 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-12 11:38 shmem info issue naveen yadav
2013-07-12 11:38 ` naveen yadav
2013-07-12 22:58 ` Hugh Dickins [this message]
2013-07-12 22:58 ` Hugh Dickins
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