----- Original Message ----
From: Mohammad M Molla <merajul_i@xxxxxxxxx>
To: kernelnewbies@xxxxxxxxxxxx
Sent: Monday, October 1, 2007 5:53:04 AM
Subject: xchg vs lock
Hi
Inside the kernel, I see in many places xchg is used to swap two pointers atomically? What is the difference between exchanging using xchg and getting lock, then exchange, then unlock? Is it only performance reason?
---------------------------------------------
xchg garantees the the atomicity of the exchange of pointes as its just one instruction. But if we do it the traditional way then we would need some protection frm other threads which might come in and change/use the valuse which are in the midist of exchanging....
CMIIW
regards
kanishk
---------------------------------------
Thanks,
- Meraj
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From: Mohammad M Molla <merajul_i@xxxxxxxxx>
To: kernelnewbies@xxxxxxxxxxxx
Sent: Monday, October 1, 2007 5:53:04 AM
Subject: xchg vs lock
Hi
Inside the kernel, I see in many places xchg is used to swap two pointers atomically? What is the difference between exchanging using xchg and getting lock, then exchange, then unlock? Is it only performance reason?
---------------------------------------------
xchg garantees the the atomicity of the exchange of pointes as its just one instruction. But if we do it the traditional way then we would need some protection frm other threads which might come in and change/use the valuse which are in the midist of exchanging....
CMIIW
regards
kanishk
---------------------------------------
Thanks,
- Meraj
Got a little couch potato?
Check out fun summer activities for kids.
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