NFSv4.1: Try to eliminate outliers when updating target_highest_slotid
Look for sudden changes in the first and second derivatives in order to eliminate outlier changes to target_highest_slotid (which are due to out-of-order RPC replies). Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Родитель
c05eecf636
Коммит
1fa8064429
|
@ -178,6 +178,8 @@ static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl,
|
||||||
tbl->highest_used_slotid = NFS4_NO_SLOT;
|
tbl->highest_used_slotid = NFS4_NO_SLOT;
|
||||||
tbl->target_highest_slotid = server_highest_slotid;
|
tbl->target_highest_slotid = server_highest_slotid;
|
||||||
tbl->server_highest_slotid = server_highest_slotid;
|
tbl->server_highest_slotid = server_highest_slotid;
|
||||||
|
tbl->d_target_highest_slotid = 0;
|
||||||
|
tbl->d2_target_highest_slotid = 0;
|
||||||
tbl->max_slotid = server_highest_slotid;
|
tbl->max_slotid = server_highest_slotid;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -292,6 +294,8 @@ void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
|
||||||
{
|
{
|
||||||
spin_lock(&tbl->slot_tbl_lock);
|
spin_lock(&tbl->slot_tbl_lock);
|
||||||
nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
|
nfs41_set_target_slotid_locked(tbl, target_highest_slotid);
|
||||||
|
tbl->d_target_highest_slotid = 0;
|
||||||
|
tbl->d2_target_highest_slotid = 0;
|
||||||
spin_unlock(&tbl->slot_tbl_lock);
|
spin_unlock(&tbl->slot_tbl_lock);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -307,16 +311,65 @@ static void nfs41_set_server_slotid_locked(struct nfs4_slot_table *tbl,
|
||||||
tbl->server_highest_slotid = highest_slotid;
|
tbl->server_highest_slotid = highest_slotid;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
static s32 nfs41_derivative_target_slotid(s32 s1, s32 s2)
|
||||||
|
{
|
||||||
|
s1 -= s2;
|
||||||
|
if (s1 == 0)
|
||||||
|
return 0;
|
||||||
|
if (s1 < 0)
|
||||||
|
return (s1 - 1) >> 1;
|
||||||
|
return (s1 + 1) >> 1;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int nfs41_sign_s32(s32 s1)
|
||||||
|
{
|
||||||
|
if (s1 > 0)
|
||||||
|
return 1;
|
||||||
|
if (s1 < 0)
|
||||||
|
return -1;
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
static bool nfs41_same_sign_or_zero_s32(s32 s1, s32 s2)
|
||||||
|
{
|
||||||
|
if (!s1 || !s2)
|
||||||
|
return true;
|
||||||
|
return nfs41_sign_s32(s1) == nfs41_sign_s32(s2);
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Try to eliminate outliers by checking for sharp changes in the
|
||||||
|
* derivatives and second derivatives
|
||||||
|
*/
|
||||||
|
static bool nfs41_is_outlier_target_slotid(struct nfs4_slot_table *tbl,
|
||||||
|
u32 new_target)
|
||||||
|
{
|
||||||
|
s32 d_target, d2_target;
|
||||||
|
bool ret = true;
|
||||||
|
|
||||||
|
d_target = nfs41_derivative_target_slotid(new_target,
|
||||||
|
tbl->target_highest_slotid);
|
||||||
|
d2_target = nfs41_derivative_target_slotid(d_target,
|
||||||
|
tbl->d_target_highest_slotid);
|
||||||
|
/* Is first derivative same sign? */
|
||||||
|
if (nfs41_same_sign_or_zero_s32(d_target, tbl->d_target_highest_slotid))
|
||||||
|
ret = false;
|
||||||
|
/* Is second derivative same sign? */
|
||||||
|
if (nfs41_same_sign_or_zero_s32(d2_target, tbl->d2_target_highest_slotid))
|
||||||
|
ret = false;
|
||||||
|
tbl->d_target_highest_slotid = d_target;
|
||||||
|
tbl->d2_target_highest_slotid = d2_target;
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
|
void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
|
||||||
struct nfs4_slot *slot,
|
struct nfs4_slot *slot,
|
||||||
struct nfs4_sequence_res *res)
|
struct nfs4_sequence_res *res)
|
||||||
{
|
{
|
||||||
spin_lock(&tbl->slot_tbl_lock);
|
spin_lock(&tbl->slot_tbl_lock);
|
||||||
if (tbl->generation != slot->generation)
|
if (!nfs41_is_outlier_target_slotid(tbl, res->sr_target_highest_slotid))
|
||||||
goto out;
|
|
||||||
nfs41_set_server_slotid_locked(tbl, res->sr_highest_slotid);
|
|
||||||
nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid);
|
nfs41_set_target_slotid_locked(tbl, res->sr_target_highest_slotid);
|
||||||
out:
|
if (tbl->generation == slot->generation)
|
||||||
|
nfs41_set_server_slotid_locked(tbl, res->sr_highest_slotid);
|
||||||
spin_unlock(&tbl->slot_tbl_lock);
|
spin_unlock(&tbl->slot_tbl_lock);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
|
@ -38,6 +38,8 @@ struct nfs4_slot_table {
|
||||||
* op for dynamic resizing */
|
* op for dynamic resizing */
|
||||||
u32 target_highest_slotid; /* Server max_slot target */
|
u32 target_highest_slotid; /* Server max_slot target */
|
||||||
u32 server_highest_slotid; /* Server highest slotid */
|
u32 server_highest_slotid; /* Server highest slotid */
|
||||||
|
s32 d_target_highest_slotid; /* Derivative */
|
||||||
|
s32 d2_target_highest_slotid; /* 2nd derivative */
|
||||||
unsigned long generation; /* Generation counter for
|
unsigned long generation; /* Generation counter for
|
||||||
target_highest_slotid */
|
target_highest_slotid */
|
||||||
struct completion complete;
|
struct completion complete;
|
||||||
|
|
Загрузка…
Ссылка в новой задаче