Messages in this thread | | | Subject | Strange Virtual Memory Mapping...! | Date | Fri, 30 Sep 2005 18:28:58 +0530 | From | "Arijit Das" <> |
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I have RH3.0 installed in an AMD64 machine.
In this system, when I look at the virtual address space mappings of a process (say a sleep process), I see quite a few strange memory region mappings which are neither readable, nor writable/executable and all of them are Private (i.e. unshared). Check this:
1024 ---p /lib64/tls/libc-2.3.2.so 1024 ---p /lib64/tls/libm-2.3.2.so 1024 ---p /lib64/tls/librtkaio-2.3.2.so 1024 ---p /lib64/tls/libpthread-0.60.so
On the other hand, when I look at the same info in a Rh7.2 system, I don't see anything like that...
Question: How do I make sense of an unreadable/unwritable/unexecutable privately mapped memory region? What is its usage? It looks like a 100% wastage of the process's address space. How is the process using it? Any idea...anybody?
You can find the sample "sleep" commands below.
Thanks, Arijit
RH3.0 on AMD64: ============= vgamd126:arijit>sleep 400 &
[1] 19916 vgamd126:arijit>pmap 19916 Size (KB) Perm Associated files (if any) ========== ==== ============================================= 16 r-xp /bin/sleep 4 rw-p /bin/sleep 132 rwxp 1108 r-xp /lib64/ld-2.3.2.so 4 rw-p /lib64/ld-2.3.2.so 4 rw-p 540 r-xp /lib64/tls/libm-2.3.2.so 1024 ---p /lib64/tls/libm-2.3.2.so 4 rw-p /lib64/tls/libm-2.3.2.so 4 rw-p 36 r-xp /lib64/tls/librtkaio-2.3.2.so 1024 ---p /lib64/tls/librtkaio-2.3.2.so 4 rw-p /lib64/tls/librtkaio-2.3.2.so 64 rw-p 1260 r-xp /lib64/tls/libc-2.3.2.so 1024 ---p /lib64/tls/libc-2.3.2.so 20 rw-p /lib64/tls/libc-2.3.2.so 16 rw-p 60 r-xp /lib64/tls/libpthread-0.60.so 1024 ---p /lib64/tls/libpthread-0.60.so 4 rw-p /lib64/tls/libpthread-0.60.so 20 rw-p 31396 r--p /usr/lib/locale/locale-archive 24 rw-p Total Virtual Memory = 38816 KB vgamd126:arijit> RH7.2 in i686 ========== eurika120:arijit>sleep 400 &
[1] 11065 eurika120:arijit>pmap 11065 Size (KB) Perm Associated files (if any) ========== ==== ============================================= 12 r-xp /bin/sleep 4 rw-p /bin/sleep 8 rwxp 88 r-xp /lib/ld-2.2.4.so 4 rw-p /lib/ld-2.2.4.so 4 r--p /usr/lib/locale/en_US/LC_IDENTIFICATION 4 r--p /usr/lib/locale/en_US/LC_MEASUREMENT 4 r--p /usr/lib/locale/en_US/LC_TELEPHONE 4 r--p /usr/lib/locale/en_US/LC_ADDRESS 4 r--p /usr/lib/locale/en_US/LC_NAME 4 r--p /usr/lib/locale/en_US/LC_PAPER 4 r--p /usr/lib/locale/en_US/LC_MESSAGES/SYS_LC_MESSAGES 4 r--p /usr/lib/locale/en_US/LC_MONETARY 24 r--p /usr/lib/locale/en_US/LC_COLLATE 4 r--p /usr/lib/locale/en_US/LC_TIME 4 r--p /usr/lib/locale/en_US/LC_NUMERIC 4 rw-p 136 r-xp /lib/i686/libm-2.2.4.so 4 rw-p /lib/i686/libm-2.2.4.so 28 r-xp /lib/librt-2.2.4.so 4 rw-p /lib/librt-2.2.4.so 40 rw-p 1224 r-xp /lib/i686/libc-2.2.4.so 20 rw-p /lib/i686/libc-2.2.4.so 16 rw-p 52 r-xp /lib/i686/libpthread-0.9.so 32 rw-p /lib/i686/libpthread-0.9.so 172 r--p /usr/lib/locale/en_US/LC_CTYPE 24 rwxp Total Virtual Memory = 1936 KB eurika120:arijit> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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