Not completely… usually the applications use some amount of shared memory too (e.g. shared libraries which are loaded into memory only once for a number of apps).
________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of raid fifa Sent: Monday, September 20, 2010 12:32 PM To: Red Hat Enterprise Linux 5 (Tikanga) discussion mailing-list Subject: Re: [rhelv5-list] mismatch between top and free -m sorry for my puzzled email. I mean "used memory" of free should be around equal to SUM of the values of RES column from top cmd. Is that right? or my mis-understand? *^_^* --- 10年9月20日，周一, John Haxby <[email protected]> 写道： 发件人: John Haxby <[email protected]> 主题: Re: [rhelv5-list] mismatch between top and free -m 收件人: "Red Hat Enterprise Linux 5 (Tikanga) discussion mailing-list" <[email protected]> 日期: 2010年9月20日,周一,下午5:26 On 20 September 2010 08:35, raid fifa <[email protected]> wrote: !179 $ free -m total used free shared buffers cached Mem: 15925 15837 88 0 76 7408 -/+ buffers/cache: 8352 7573 Swap: 8189 0 8189 top - 03:34:23 up 29 days, 6:15, 5 users, load average: 3.92, 3.72, 2.70 Tasks: 172 total, 1 running, 171 sleeping, 0 stopped, 0 zombie Cpu(s): 23.2%us, 3.1%sy, 0.0%ni, 63.4%id, 9.7%wa, 0.0%hi, 0.6%si, 0.0%st Mem: 16307832k total, 16222676k used, 85156k free, 78732k buffers Swap: 8385920k total, 148k used, 8385772k free, 8372932k cached Which numbers do you think are inconsistent? There's a minor discrepancy between the "free -m" free and the top free (85156/1024 == 83 vs 88) but those 5MB could just be down to timing. Both free and top get their statistics from /proc/meminfo so any inconsistencies you think you're seeing are simply in the way that the utility chooses to represent the information. As Morgan Langley says, though, the "+-/ buffers/cached" line in the output of free is sometimes confusing, but it just subtracts or adds 76+7408 from the "used" and "free" values respectively (there's a bit of a rounding error in there though). The premise here is that "buffers" and "cached" can be quickly freed if needed -- that's only true up to a point. If you want to know exactly what values from /proc/meminfo are being used and how then you'll have to dig into the source code of free and top. After that you're down to getting the developers to justify their choices; and they may not know! jch -----下面为附件内容----- _______________________________________________ rhelv5-list mailing list [email protected] https://www.redhat.com/mailman/listinfo/rhelv5-list
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