xfs: optimize bio handling in the buffer writeback path

This patch implements two closely related changes:  First it embeds
a bio the ioend structure so that we don't have to allocate one
separately.  Second it uses the block layer bio chaining mechanism
to chain additional bios off this first one if needed instead of
manually accounting for multiple bio completions in the ioend
structure.  Together this removes a memory allocation per ioend and
greatly simplifies the ioend setup and I/O completion path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Christoph Hellwig
2016-04-06 08:34:30 +10:00
committed by Dave Chinner
parent 37992c18bb
commit 0e51a8e191
3 changed files with 123 additions and 165 deletions

View File

@@ -58,8 +58,7 @@
#include <linux/parser.h>
static const struct super_operations xfs_super_operations;
static kmem_zone_t *xfs_ioend_zone;
mempool_t *xfs_ioend_pool;
struct bio_set *xfs_ioend_bioset;
static struct kset *xfs_kset; /* top-level xfs sysfs dir */
#ifdef DEBUG
@@ -1688,20 +1687,15 @@ MODULE_ALIAS_FS("xfs");
STATIC int __init
xfs_init_zones(void)
{
xfs_ioend_zone = kmem_zone_init(sizeof(xfs_ioend_t), "xfs_ioend");
if (!xfs_ioend_zone)
xfs_ioend_bioset = bioset_create(4 * MAX_BUF_PER_PAGE,
offsetof(struct xfs_ioend, io_inline_bio));
if (!xfs_ioend_bioset)
goto out;
xfs_ioend_pool = mempool_create_slab_pool(4 * MAX_BUF_PER_PAGE,
xfs_ioend_zone);
if (!xfs_ioend_pool)
goto out_destroy_ioend_zone;
xfs_log_ticket_zone = kmem_zone_init(sizeof(xlog_ticket_t),
"xfs_log_ticket");
if (!xfs_log_ticket_zone)
goto out_destroy_ioend_pool;
goto out_free_ioend_bioset;
xfs_bmap_free_item_zone = kmem_zone_init(sizeof(xfs_bmap_free_item_t),
"xfs_bmap_free_item");
@@ -1797,10 +1791,8 @@ xfs_init_zones(void)
kmem_zone_destroy(xfs_bmap_free_item_zone);
out_destroy_log_ticket_zone:
kmem_zone_destroy(xfs_log_ticket_zone);
out_destroy_ioend_pool:
mempool_destroy(xfs_ioend_pool);
out_destroy_ioend_zone:
kmem_zone_destroy(xfs_ioend_zone);
out_free_ioend_bioset:
bioset_free(xfs_ioend_bioset);
out:
return -ENOMEM;
}
@@ -1826,9 +1818,7 @@ xfs_destroy_zones(void)
kmem_zone_destroy(xfs_btree_cur_zone);
kmem_zone_destroy(xfs_bmap_free_item_zone);
kmem_zone_destroy(xfs_log_ticket_zone);
mempool_destroy(xfs_ioend_pool);
kmem_zone_destroy(xfs_ioend_zone);
bioset_free(xfs_ioend_bioset);
}
STATIC int __init