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Cisco IOS has a monolithic architecture.
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sync_mapping_buffers(9) [centos man page]

SYNC_MAPPING_BUFFERS(9) 					   The Linux VFS					   SYNC_MAPPING_BUFFERS(9)

NAME
sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers SYNOPSIS
int sync_mapping_buffers(struct address_space * mapping); ARGUMENTS
mapping the mapping which wants those buffers written DESCRIPTION
Starts I/O against the buffers at mapping->private_list, and waits upon that I/O. Basically, this is a convenience function for fsync. mapping is a file or directory which needs those buffers to be written for a successful fsync. COPYRIGHT
Kernel Hackers Manual 3.10 June 2014 SYNC_MAPPING_BUFFERS(9)

Check Out this Related Man Page

MPAGE_READPAGES(9)						   The Linux VFS						MPAGE_READPAGES(9)

NAME
mpage_readpages - populate an address space with some pages & start reads against them SYNOPSIS
int mpage_readpages(struct address_space * mapping, struct list_head * pages, unsigned nr_pages, get_block_t get_block); ARGUMENTS
mapping the address_space pages The address of a list_head which contains the target pages. These pages have their ->index populated and are otherwise uninitialised. The page at pages->prev has the lowest file offset, and reads should be issued in pages->prev to pages->next order. nr_pages The number of pages at *pages get_block The filesystem's block mapper function. DESCRIPTION
This function walks the pages and the blocks within each page, building and emitting large BIOs. If anything unusual happens, such as: - encountering a page which has buffers - encountering a page which has a non-hole after a hole - encountering a page with non-contiguous blocks then this code just gives up and calls the buffer_head-based read function. It does handle a page which has holes at the end - that is a common case: the end-of-file on blocksize < PAGE_CACHE_SIZE setups. BH_BOUNDARY EXPLANATION There is a problem. The mpage read code assembles several pages, gets all their disk mappings, and then submits them all. That's fine, but obtaining the disk mappings may require I/O. Reads of indirect blocks, for example. So an mpage read of the first 16 blocks of an ext2 file will cause I/O to be SUBMITTED IN THE FOLLOWING ORDER
12 0 1 2 3 4 5 6 7 8 9 10 11 13 14 15 16 because the indirect block has to be read to get the mappings of blocks 13,14,15,16. Obviously, this impacts performance. So what we do it to allow the filesystem's get_block function to set BH_Boundary when it maps block 11. BH_Boundary says: mapping of the block after this one will require I/O against a block which is probably close to this one. So you should push what I/O you have currently accumulated. This all causes the disk requests to be issued in the correct order. COPYRIGHT
Kernel Hackers Manual 3.10 June 2014 MPAGE_READPAGES(9)

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