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Full Discussion: High use of cache memory
Top Forums UNIX for Dummies Questions & Answers High use of cache memory Post 302372408 by thegeek on Wednesday 18th of November 2009 12:24:57 AM
Old 11-18-2009
Code:
 The first row, labeled Mem, displays physical memory utilization, including the amount of memory allocated to buffers and caches.
A buffer, also called buffer memory, is usually defined as a portion of memory that is set aside as a temporary holding place for 
data that is being sent to or received from an external device, such as a HDD, keyboard,
printer or network.  
   The second line of data, which begins with -/+ buffers/cache, shows the amount of physical memory currently devoted to system buffer 
cache. This is particularly meaningful with regard to application programs, as all data 
accessed from files on the system that are performed through the use of read() and write() 
system calls1 pass through this cache. This cache can greatly speed up access to data 
by reducing or eliminating the need to read from or write to the HDD or other disk.

From the web page: How to use the "free" command, by The Linux Information Project (LINFO)


Hope it helps.
 

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KCALLOC(9)						    Memory Management in Linux							KCALLOC(9)

NAME
kcalloc - allocate memory for an array. The memory is set to zero. SYNOPSIS
void * kcalloc(size_t n, size_t size, gfp_t flags); ARGUMENTS
n number of elements. size element size. flags the type of memory to allocate. DESCRIPTION
The flags argument may be one of: GFP_USER - Allocate memory on behalf of user. May sleep. GFP_KERNEL - Allocate normal kernel ram. May sleep. GFP_ATOMIC - Allocation will not sleep. May use emergency pools. For example, use this inside interrupt handlers. GFP_HIGHUSER - Allocate pages from high memory. GFP_NOIO - Do not do any I/O at all while trying to get memory. GFP_NOFS - Do not make any fs calls while trying to get memory. GFP_NOWAIT - Allocation will not sleep. GFP_THISNODE - Allocate node-local memory only. GFP_DMA - Allocation suitable for DMA. Should only be used for kmalloc caches. Otherwise, use a slab created with SLAB_DMA. Also it is possible to set different flags by OR'ing in one or more of the following additional flags: __GFP_COLD - Request cache-cold pages instead of trying to return cache-warm pages. __GFP_HIGH - This allocation has high priority and may use emergency pools. __GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail (think twice before using). __GFP_NORETRY - If memory is not immediately available, then give up at once. __GFP_NOWARN - If allocation fails, don't issue any warnings. __GFP_REPEAT - If allocation fails initially, try once more before failing. There are other flags available as well, but these are not intended for general use, and so are not documented here. For a full list of potential flags, always refer to linux/gfp.h. COPYRIGHT
Kernel Hackers Manual 2.6. July 2010 KCALLOC(9)
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