Messages in this thread | | | Date | Sat, 13 Dec 2003 09:42:10 +0900 (JST) | Subject | Re: sysctl vs /proc/sys | From | YOSHIFUJI Hideaki / 吉藤英明 <> |
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In article <20031212181517.GM15401@matchmail.com> (at Fri, 12 Dec 2003 10:15:17 -0800), Mike Fedyk <mfedyk@matchmail.com> says:
> On Fri, Dec 12, 2003 at 09:28:32AM -0500, James Morris wrote: > > On Fri, 12 Dec 2003, YOSHIFUJI Hideaki / [iso-2022-jp] 吉藤英明 wrote: > > > > > Can we get the exact previous value from /proc/sys atomicly? > > > > I'm not sure what you mean by this. > > Read value and modify in one op?
Yes, I meant to read old value and to set new one in one system call. The sysctl system-call does lock_kernel, so sysctl(2) sytem-call are serialized.
How about procfs? Are there locks between multiple read-and-write? Since It seems user-space cannot (or even should not) let kernel hold lock(s) during read-and-write operation, procfs cannot be the alternative.
Do I mis-understand something?
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