问题
I am now study linux. cat /proc/meminfo produces as following. Please tell me the mean of entry "Active(file)/Inactive(file)". I can't find the explanation of these entry. Thanks.
MemTotal: 7736104 kB
MemFree: 166580 kB
Buffers: 604636 kB
Cached: 5965376 kB
SwapCached: 0 kB
Active: 4294464 kB
Inactive: 2319240 kB
Active(anon): 13688 kB
Inactive(anon): 33828 kB
Active(file): 4280776 kB
Inactive(file): 2285412 kB
Unevictable: 0 kB
Mlocked: 0 kB
SwapTotal: 16777208 kB
SwapFree: 16777208 kB
Dirty: 0 kB
Writeback: 0 kB
AnonPages: 43772 kB
Mapped: 11056 kB
Shmem: 3792 kB
Slab: 861004 kB
SReclaimable: 818040 kB
SUnreclaim: 42964 kB
KernelStack: 1624 kB
PageTables: 5460 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 20645260 kB
Committed_AS: 124392 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 450644 kB
VmallocChunk: 34359282660 kB
HardwareCorrupted: 0 kB
AnonHugePages: 2048 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
DirectMap4k: 16384 kB
DirectMap2M: 3880960 kB
DirectMap1G: 4194304 kB
回答1:
According to the output, result of Active(file) + Inactive(file) + Shmem doesn't equal to that of Cached + Buffer + SwapCached
回答2:
Active — The total amount of buffer or page cache memory, in kilobytes, that is in active use. This is memory that has been recently used and is usually not reclaimed for other purposes.
Inactive — The total amount of buffer or page cache memory, in kilobytes, that are free and and available. This is memory that has not been recently used and can be reclaimed for other purposes.
Ref : https://www.centos.org/docs/5/html/5.1/Deployment_Guide/s2-proc-meminfo.html
回答3:
And FYI.
- Active = Active(anon) + Active(file) Inactive = Inactive(anon) + Inactive(file)
- Active(file), Inactive(file) has file back-end which means its original file is in disk but to use it faster it was loaded on RAM.
- Active(file) + Inactive(file) + Shmem = Cached + Buffer + SwapCached
来源：https://stackoverflow.com/questions/24484481/entry-in-proc-meminfo