Module Name: src
Committed By: jdolecek
Date: Thu Apr 23 08:09:25 UTC 2020
Modified Files:
src/sys/arch/xen/xen: xbdback_xenbus.c
Log Message:
allocate xbdback_io instances as part of struct xbdback_instance and
stop using pool_cache(9), to remove possibility for the allocation to sleep
To generate a diff of this commit:
cvs rdiff -u -r1.88 -r1.89 src/sys/arch/xen/xen/xbdback_xenbus.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/xen/xen/xbdback_xenbus.c
diff -u src/sys/arch/xen/xen/xbdback_xenbus.c:1.88 src/sys/arch/xen/xen/xbdback_xenbus.c:1.89
--- src/sys/arch/xen/xen/xbdback_xenbus.c:1.88 Thu Apr 23 07:39:07 2020
+++ src/sys/arch/xen/xen/xbdback_xenbus.c Thu Apr 23 08:09:25 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: xbdback_xenbus.c,v 1.88 2020/04/23 07:39:07 jdolecek Exp $ */
+/* $NetBSD: xbdback_xenbus.c,v 1.89 2020/04/23 08:09:25 jdolecek Exp $ */
/*
* Copyright (c) 2006 Manuel Bouyer.
@@ -26,7 +26,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xbdback_xenbus.c,v 1.88 2020/04/23 07:39:07 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xbdback_xenbus.c,v 1.89 2020/04/23 08:09:25 jdolecek Exp $");
#include <sys/atomic.h>
#include <sys/buf.h>
@@ -142,6 +142,41 @@ struct xbdback_va {
vaddr_t xv_vaddr;
};
+/*
+ * For each I/O operation associated with one of those requests, an
+ * xbdback_io is allocated from a pool. It may correspond to multiple
+ * Xen disk requests, or parts of them, if several arrive at once that
+ * can be coalesced.
+ */
+struct xbdback_io {
+ SLIST_ENTRY(xbdback_io) xio_next;
+ /* The instance pointer is duplicated for convenience. */
+ struct xbdback_instance *xio_xbdi; /* our xbd instance */
+ uint8_t xio_operation;
+ uint64_t xio_id;
+ union {
+ struct {
+ struct buf xio_buf; /* our I/O */
+ /* the virtual address to map the request at */
+ vaddr_t xio_vaddr;
+ struct xbdback_va *xio_xv;
+ vaddr_t xio_start_offset; /* I/O start offset */
+ /* grants to map */
+ grant_ref_t xio_gref[VBD_MAX_INDIRECT_SEGMENTS];
+ /* grants release */
+ grant_handle_t xio_gh[VBD_MAX_INDIRECT_SEGMENTS];
+ uint16_t xio_nrma; /* number of guest pages */
+ } xio_rw;
+ } u;
+};
+#define xio_buf u.xio_rw.xio_buf
+#define xio_vaddr u.xio_rw.xio_vaddr
+#define xio_start_offset u.xio_rw.xio_start_offset
+#define xio_xv u.xio_rw.xio_xv
+#define xio_gref u.xio_rw.xio_gref
+#define xio_gh u.xio_rw.xio_gh
+#define xio_nrma u.xio_rw.xio_nrma
+
/* we keep the xbdback instances in a linked list */
struct xbdback_instance {
SLIST_ENTRY(xbdback_instance) next;
@@ -154,7 +189,9 @@ struct xbdback_instance {
kmutex_t xbdi_lock;
kcondvar_t xbdi_cv; /* wait channel for thread work */
xbdback_state_t xbdi_status; /* thread's status */
- /* KVA for mapping transfers */
+ /* context and KVA for mapping transfers */
+ struct xbdback_io xbdi_io[BLKIF_RING_SIZE];
+ SLIST_HEAD(, xbdback_io) xbdi_io_free;
struct xbdback_va xbdi_va[BLKIF_RING_SIZE];
SLIST_HEAD(, xbdback_va) xbdi_va_free;
/* backing device parameters */
@@ -200,46 +237,6 @@ do {
static SLIST_HEAD(, xbdback_instance) xbdback_instances;
static kmutex_t xbdback_lock;
-/*
- * For each I/O operation associated with one of those requests, an
- * xbdback_io is allocated from a pool. It may correspond to multiple
- * Xen disk requests, or parts of them, if several arrive at once that
- * can be coalesced.
- */
-struct xbdback_io {
- /* The instance pointer is duplicated for convenience. */
- struct xbdback_instance *xio_xbdi; /* our xbd instance */
- uint8_t xio_operation;
- uint64_t xio_id;
- union {
- struct {
- struct buf xio_buf; /* our I/O */
- /* the virtual address to map the request at */
- vaddr_t xio_vaddr;
- struct xbdback_va *xio_xv;
- vaddr_t xio_start_offset; /* I/O start offset */
- /* grants to map */
- grant_ref_t xio_gref[VBD_MAX_INDIRECT_SEGMENTS];
- /* grants release */
- grant_handle_t xio_gh[VBD_MAX_INDIRECT_SEGMENTS];
- uint16_t xio_nrma; /* number of guest pages */
- } xio_rw;
- } u;
-};
-#define xio_buf u.xio_rw.xio_buf
-#define xio_vaddr u.xio_rw.xio_vaddr
-#define xio_start_offset u.xio_rw.xio_start_offset
-#define xio_xv u.xio_rw.xio_xv
-#define xio_gref u.xio_rw.xio_gref
-#define xio_gh u.xio_rw.xio_gh
-#define xio_nrma u.xio_rw.xio_nrma
-
-/*
- * Pools to manage the chain of block requests and I/Os fragments
- * submitted by frontend.
- */
-static struct pool_cache xbdback_io_pool;
-
/* Interval between reports of I/O errors from frontend */
static const struct timeval xbdback_err_intvl = { 1, 0 };
@@ -277,9 +274,8 @@ static void xbdback_send_reply(struct xb
static void *xbdback_map_shm(struct xbdback_io *);
static void xbdback_unmap_shm(struct xbdback_io *);
-static void *xbdback_pool_get(struct pool_cache *,
- struct xbdback_instance *);
-static void xbdback_pool_put(struct pool_cache *, void *);
+static struct xbdback_io *xbdback_io_get(struct xbdback_instance *);
+static void xbdback_io_put(struct xbdback_instance *, struct xbdback_io *);
static void xbdback_thread(void *);
static void xbdback_wakeup_thread(struct xbdback_instance *);
static void xbdback_trampoline(struct xbdback_instance *, void *);
@@ -301,13 +297,6 @@ xbdbackattach(int n)
SLIST_INIT(&xbdback_instances);
mutex_init(&xbdback_lock, MUTEX_DEFAULT, IPL_NONE);
- pool_cache_bootstrap(&xbdback_io_pool,
- sizeof(struct xbdback_io), 0, 0, 0, "xbbip", NULL,
- IPL_SOFTBIO, NULL, NULL, NULL);
-
- /* we allocate enough to handle a whole ring at once */
- pool_prime(&xbdback_io_pool.pc_pool, BLKIF_RING_SIZE);
-
xenbus_backend_register(&xbd_backend_driver);
}
@@ -346,7 +335,8 @@ xbdback_xenbus_create(struct xenbus_devi
xbusd->xbusd_path);
return EFTYPE;
}
-
+
+ /* XXXSMP unlocked search */
if (xbdif_lookup(domid, handle)) {
return EEXIST;
}
@@ -396,6 +386,12 @@ xbdback_xenbus_create(struct xenbus_devi
xv_next);
}
+ SLIST_INIT(&xbdi->xbdi_io_free);
+ for (i = 0; i < BLKIF_RING_SIZE; i++) {
+ SLIST_INSERT_HEAD(&xbdi->xbdi_io_free, &xbdi->xbdi_io[i],
+ xio_next);
+ }
+
error = xenbus_watch_path2(xbusd, xbusd->xbusd_path, "physical-device",
&xbdi->xbdi_watch, xbdback_backend_changed);
if (error) {
@@ -1107,7 +1103,7 @@ xbdback_co_cache_flush(struct xbdback_in
return NULL;
}
xbdi->xbdi_cont = xbdback_co_cache_doflush;
- return xbdback_pool_get(&xbdback_io_pool, xbdi);
+ return xbdback_io_get(xbdi);
}
/* Start the flush work */
@@ -1227,7 +1223,7 @@ xbdback_co_io(struct xbdback_instance *x
goto bad_nr_segments;
xbdi->xbdi_cont = xbdback_co_io_gotio;
- return xbdback_pool_get(&xbdback_io_pool, xbdi);
+ return xbdback_io_get(xbdi);
bad_nr_segments:
if (ratecheck(&xbdi->xbdi_lasterr_time, &xbdback_err_intvl)) {
@@ -1367,7 +1363,7 @@ xbdback_co_do_io(struct xbdback_instance
error = BLKIF_RSP_OKAY;
xbdback_send_reply(xbdi, xbd_io->xio_id,
xbd_io->xio_operation, error);
- xbdback_pool_put(&xbdback_io_pool, xbd_io);
+ xbdback_io_put(xbdi, xbd_io);
xbdi_put(xbdi);
xbdi->xbdi_cont = xbdback_co_main_incr;
return xbdi;
@@ -1430,7 +1426,7 @@ xbdback_iodone(struct buf *bp)
xbdi_put(xbdi);
atomic_dec_uint(&xbdi->xbdi_pendingreqs);
buf_destroy(&xbd_io->xio_buf);
- xbdback_pool_put(&xbdback_io_pool, xbd_io);
+ xbdback_io_put(xbdi, xbd_io);
xbdback_wakeup_thread(xbdi);
KERNEL_UNLOCK_ONE(NULL); /* XXXSMP */
@@ -1580,18 +1576,21 @@ xbdback_unmap_shm(struct xbdback_io *xbd
}
/* Obtain memory from a pool */
-static void *
-xbdback_pool_get(struct pool_cache *pc,
- struct xbdback_instance *xbdi)
+static struct xbdback_io *
+xbdback_io_get(struct xbdback_instance *xbdi)
{
- return pool_cache_get(pc, PR_WAITOK);
+ struct xbdback_io *xbd_io = SLIST_FIRST(&xbdi->xbdi_io_free);
+ KASSERT(xbd_io != NULL);
+ SLIST_REMOVE_HEAD(&xbdi->xbdi_io_free, xio_next);
+ return xbd_io;
}
/* Restore memory to a pool */
static void
-xbdback_pool_put(struct pool_cache *pc, void *item)
+xbdback_io_put(struct xbdback_instance *xbdi, struct xbdback_io *xbd_io)
{
- pool_cache_put(pc, item);
+ KASSERT(xbd_io != NULL);
+ SLIST_INSERT_HEAD(&xbdi->xbdi_io_free, xbd_io, xio_next);
}
/*
