svn commit: r195259 - head/sys/kern

[Jeff Roberson]

Author: jeff
Date: Wed Jul  1 20:43:46 2009
New Revision: 195259
URL: http://svn.freebsd.org/changeset/base/195259

Log:
   - Use fd_lastfile + 1 as the upper bound on nd.  This is more correct than
     using the size of the descriptor array.
   - A lock is not needed to fetch fd_lastfile.  The results are stale the
     instant it is dropped.
   - Use a private mutex pool for select since the pool mutex is not used
     as a leaf.
   - Fetch the si_mtx pointer first before resorting to hashing to compute
     the mutex address.
  
  Reviewed by:	McKusick
  Approved by:	re (kib)

Modified:
  head/sys/kern/sys_generic.c

Modified: head/sys/kern/sys_generic.c
==============================================================================
--- head/sys/kern/sys_generic.c	Wed Jul  1 20:42:17 2009	(r195258)
+++ head/sys/kern/sys_generic.c	Wed Jul  1 20:43:46 2009	(r195259)
@@ -124,6 +124,7 @@ struct selfd {
 };
 
 static uma_zone_t selfd_zone;
+static struct mtx_pool *mtxpool_select;
 
 #ifndef _SYS_SYSPROTO_H_
 struct read_args {
@@ -794,11 +795,8 @@ kern_select(struct thread *td, int nd, f
 	if (nd < 0)
 		return (EINVAL);
 	fdp = td->td_proc->p_fd;
-	
-	FILEDESC_SLOCK(fdp);
-	if (nd > td->td_proc->p_fd->fd_nfiles)
-		nd = td->td_proc->p_fd->fd_nfiles;   /* forgiving; slightly wrong */
-	FILEDESC_SUNLOCK(fdp);
+	if (nd > fdp->fd_lastfile + 1)
+		nd = fdp->fd_lastfile + 1;
 
 	/*
 	 * Allocate just enough bits for the non-null fd_sets.  Use the
@@ -1373,7 +1371,9 @@ selrecord(selector, sip)
 		stp->st_free2 = NULL;
 	else
 		panic("selrecord: No free selfd on selq");
-	mtxp = mtx_pool_find(mtxpool_sleep, sip);
+	mtxp = sip->si_mtx;
+	if (mtxp == NULL)
+		mtxp = mtx_pool_find(mtxpool_select, sip);
 	/*
 	 * Initialize the sfp and queue it in the thread.
 	 */
@@ -1529,6 +1529,8 @@ SYSINIT(select, SI_SUB_SYSCALLS, SI_ORDE
 static void
 selectinit(void *dummy __unused)
 {
+
 	selfd_zone = uma_zcreate("selfd", sizeof(struct selfd), NULL, NULL,
 	    NULL, NULL, UMA_ALIGN_PTR, 0);
+	mtxpool_select = mtx_pool_create("select mtxpool", 128, MTX_DEF);
 }