writeback_inodes_sb_nr(9) [centos man page]

WRITEBACK_INODES_SB_(9) 					   The Linux VFS					   WRITEBACK_INODES_SB_(9)

NAME

       writeback_inodes_sb_nr - writeback dirty inodes from given super_block

SYNOPSIS

       void writeback_inodes_sb_nr(struct super_block * sb, unsigned long nr, enum wb_reason reason);

ARGUMENTS

       sb
	   the superblock

       nr
	   the number of pages to write

       reason
	   reason why some writeback work initiated

DESCRIPTION

       Start writeback on some inodes on this super_block. No guarantees are made on how many (if any) will be written, and this function does not
       wait for IO completion of submitted IO.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						   WRITEBACK_INODES_SB_(9)

BIO_ALLOC_BIOSET(9)						   The Linux VFS					       BIO_ALLOC_BIOSET(9)

NAME

       bio_alloc_bioset - allocate a bio for I/O

SYNOPSIS

       struct bio * bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set * bs);

ARGUMENTS

       gfp_mask
	   the GFP_ mask given to the slab allocator

       nr_iovecs
	   number of iovecs to pre-allocate

       bs
	   the bio_set to allocate from.

DESCRIPTION

       If bs is NULL, uses kmalloc to allocate the bio; else the allocation is backed by the bs's mempool.

       When bs is not NULL, if __GFP_WAIT is set then bio_alloc will always be able to allocate a bio. This is due to the mempool guarantees. To
       make this work, callers must never allocate more than 1 bio at a time from this pool. Callers that need to allocate more than 1 bio must
       always submit the previously allocated bio for IO before attempting to allocate a new one. Failure to do so can cause deadlocks under
       memory pressure.

       Note that when running under generic_make_request (i.e. any block driver), bios are not submitted until after you return - see the code in
       generic_make_request that converts recursion into iteration, to prevent stack overflows.

       This would normally mean allocating multiple bios under generic_make_request would be susceptible to deadlocks, but we have deadlock
       avoidance code that resubmits any blocked bios from a rescuer thread.

       However, we do not guarantee forward progress for allocations from other mempools. Doing multiple allocations from the same mempool under
       generic_make_request should be avoided - instead, use bio_set's front_pad for per bio allocations.

RETURNS

       Pointer to new bio on success, NULL on failure.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						       BIO_ALLOC_BIOSET(9)