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NFSv4.1: coelesce across layout stripes

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Add a pg_test layout driver hook which is used to avoid coelescing I/O across
layout stripes.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Andy Adamson <andros@citi.umich.edu>
Signed-off-by: Dean Hildebrand <dhildeb@us.ibm.com>
Signed-off-by: Fred Isaman <iisaman@citi.umich.edu>
Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Tao Guo <guotao@nrchpc.ac.cn>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Fred Isaman 2011-03-01 01:34:14 +00:00 • committed by Trond Myklebust
parent d684d2ae10
commit 94ad1c80e2
7 changed files with 70 additions and 2 deletions
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26
fs/nfs/nfs4filelayout.c
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@ -252,6 +252,31 @@ filelayout_free_lseg(struct pnfs_layout_segment *lseg)
_filelayout_free_lseg(fl);
}
/*
* filelayout_pg_test(). Called by nfs_can_coalesce_requests()
*
* return 1 : coalesce page
* return 0 : don't coalesce page
*/
int
filelayout_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
struct nfs_page *req)
{
u64 p_stripe, r_stripe;
u32 stripe_unit;
if (!pgio->pg_lseg)
return 1;
p_stripe = (u64)prev->wb_index << PAGE_CACHE_SHIFT;
r_stripe = (u64)req->wb_index << PAGE_CACHE_SHIFT;
stripe_unit = FILELAYOUT_LSEG(pgio->pg_lseg)->stripe_unit;
do_div(p_stripe, stripe_unit);
do_div(r_stripe, stripe_unit);
return (p_stripe == r_stripe);
}
static struct pnfs_layoutdriver_type filelayout_type = {
.id = LAYOUT_NFSV4_1_FILES,
.name = "LAYOUT_NFSV4_1_FILES",
@ -260,6 +285,7 @@ static struct pnfs_layoutdriver_type filelayout_type = {
.clear_layoutdriver = filelayout_clear_layoutdriver,
.alloc_lseg = filelayout_alloc_lseg,
.free_lseg = filelayout_free_lseg,
.pg_test = filelayout_pg_test,
};
static int __init nfs4filelayout_init(void)