sar -B 可以提供内存相关的指标
pgpgin/s:从磁盘读入内存
Total number of kilobytes the system paged in from disk per second.
pgpgout/s: 从内存写入磁盘
Total number of kilobytes the system paged out to disk per second.
fault/s:系统产生的缺页异常
Number of page faults (major + minor) made by the system per second. This is not a count of page faults that generate I/O, because some page faults can be resolved without I/O.
majflt/s:由swap和shmem产生的缺页异常
Number of major faults the system has made per second, those which have required loading a memory page from disk.
pgfree/s: 释放page到伙伴系统
Number of pages placed on the free list by the system per second.
pgscank/s : kswap线程扫描的页面
Number of pages scanned by the kswapd daemon per second.
pgscand/s：直接内存回收扫描的页面内存相关性能指标
Number of pages scanned directly per second.内存相关性能指标
pgsteal/s:从swap和cache中回收的页面
Number of pages the system has reclaimed from cache (pagecache and swapcache) per second to satisfy its memory demands.
%vmeff：pgsteal/(pgscank+pgscank) 数值越大，表示能够被回收的页表更多.
Calculated as pgsteal / pgscan, this is a metric of the efficiency of page reclaim. If it is near 100% then almost every page coming off the tail of the inactive list is being reaped. If it gets too low (e.g. less than 30%) then the virtual memory is having some difficulty. This field is displayed as zero if no pages have been scanned during the interval of time.