Hello all,
I am still trying to get AFS on 2.6.16 linux.
The latest snapshots, and 1.5.0 have a new routine in afs_callback.c
which does not compile:
'struct dentry’ has no member named ‘d_child'
This seems to be due to the patch at the bottom.
So now we have:
/*
* d_child and d_rcu can share memory
*/
union {
struct list_head d_child; /* child of parent list */
struct rcu_head d_rcu;
} d_u;
Does anyone know how should this be d_child be referenced?
d_u.d_cache is wrong...
Thank you,
Bill
============================================================================
commit 5160ee6fc891a9ca114be0e90fa6655647bb64b2
Author: Eric Dumazet <[EMAIL PROTECTED]>
Date: Sun Jan 8 01:03:32 2006 -0800
[PATCH] shrink dentry struct
Some long time ago, dentry struct was carefully tuned so that on 32 bits
UP, sizeof(struct dentry) was exactly 128, ie a power of 2, and a
multiple
of memory cache lines.
Then RCU was added and dentry struct enlarged by two pointers, with nice
results for SMP, but not so good on UP, because breaking the above
tuning
(128 + 8 = 136 bytes)
This patch reverts this unwanted side effect, by using an union (d_u),
where d_rcu and d_child are placed so that these two fields can share
their memory needs.
At the time d_free() is called (and d_rcu is really used), d_child is
known to be empty and not touched by the dentry freeing.
Lockless lookups only access d_name, d_parent, d_lock, d_op, d_flags (so
the previous content of d_child is not needed if said dentry was
unhashed
but still accessed by a CPU because of RCU constraints)
As dentry cache easily contains millions of entries, a size reduction is
worth the extra complexity of the ugly C union.
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