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[root@server ~]# free -m
total used free shared buffers cached
Mem: 249 163 86 0 10 94
-/+ buffers/cache: 58 191
Swap: 511 0 511
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used ÒѾʹÓõÄÄÚ´æÊý
free ¿ÕÏеÄÄÚ´æÊý
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buffers Buffer CacheºÍcached Page Cache ´ÅÅÌ»º´æµÄ´óС
-buffers/cache µÄÄÚ´æÊý:used - buffers - cached
+buffers/cache µÄÄÚ´æÊý:free + buffers + cached
¿ÉÓõÄmemory=free memory+buffers+cached
ÓÐÁËÕâ¸ö»ù´¡ºó,¿ÉÒÔµÃÖª,ÎÒÏÖÔÚusedΪ163MB,freeΪ86,bufferºÍcached·Ö±ðΪ10,94
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[root@server ~]# cp -r /etc ~/test/
[root@server ~]# free -m
total used free shared buffers cached
Mem: 249 244 4 0 8 174
-/+ buffers/cache: 62 187
Swap: 511 0 511
ÔÚÎÒÃüÁîÖ´ÐнáÊøºó,usedΪ244MB,freeΪ4MB,buffersΪ8MB,cachedΪ174MB,ÌìÄŶ¼±»cached³ÔµôÁË.±ð½ôÕÅ,ÕâÊÇΪÁËÌá¸ßÎļþ¶ÁȡЧÂʵÄ×ö·¨.
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ÄÇôÓÐÈË˵¹ý¶Îʱ¼ä,linux»á×Ô¶¯ÊͷŵôËùÓõÄÄÚ´æ,ÎÒÃÇʹÓÃfreeÔÙÀ´ÊÔÊÔ,¿´¿´ÊÇ·ñÓÐÊÍ·Å>?
[root@server test]# free -m
total used free shared buffers cached
Mem: 249 244 5 0 8 174
-/+ buffers/cache: 61 188
Swap: 511 0 511
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/procÊÇÒ»¸öÐéÄâÎļþϵͳ,ÎÒÃÇ¿ÉÒÔͨ¹ý¶ÔËüµÄ¶Áд²Ù×÷×öΪÓëkernelʵÌå¼ä½øÐÐͨÐŵÄÒ»ÖÖÊÖ¶Î.Ò²¾ÍÊÇ˵¿ÉÒÔͨ¹ýÐÞ¸Ä/procÖеÄÎļþ,À´¶Ôµ±Ç°kernelµÄÐÐΪ×ö³öµ÷Õû.ÄÇôÎÒÃÇ¿ÉÒÔͨ¹ýµ÷Õû/proc/sys/vm/drop_cachesÀ´ÊÍ·ÅÄÚ´æ.²Ù×÷ÈçÏÂ:
[root@server test]# cat /proc/sys/vm/drop_caches
0
Ê×ÏÈ,/proc/sys/vm/drop_cac
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