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[src/trunk]: src/sys/kern optionally use FUA instead of full cache sync, and ...
details: https://anonhg.NetBSD.org/src/rev/27be80ce44ec
branches: trunk
changeset: 822756:27be80ce44ec
user: jdolecek <jdolecek%NetBSD.org@localhost>
date: Wed Apr 05 20:38:53 2017 +0000
description:
optionally use FUA instead of full cache sync, and DPO for journal writes,
when supported by disk device; controlled by sysctl vfs.wapbl.allow_fuadpo,
default off for now
discussed on tech-kern
diffstat:
sys/kern/vfs_wapbl.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++-----
1 files changed, 70 insertions(+), 9 deletions(-)
diffs (187 lines):
diff -r c43c6d315f3a -r 27be80ce44ec sys/kern/vfs_wapbl.c
--- a/sys/kern/vfs_wapbl.c Wed Apr 05 20:30:55 2017 +0000
+++ b/sys/kern/vfs_wapbl.c Wed Apr 05 20:38:53 2017 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: vfs_wapbl.c,v 1.92 2017/03/17 03:19:46 riastradh Exp $ */
+/* $NetBSD: vfs_wapbl.c,v 1.93 2017/04/05 20:38:53 jdolecek Exp $ */
/*-
* Copyright (c) 2003, 2008, 2009 The NetBSD Foundation, Inc.
@@ -36,7 +36,7 @@
#define WAPBL_INTERNAL
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_wapbl.c,v 1.92 2017/03/17 03:19:46 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_wapbl.c,v 1.93 2017/04/05 20:38:53 jdolecek Exp $");
#include <sys/param.h>
#include <sys/bitops.h>
@@ -71,6 +71,7 @@
static struct sysctllog *wapbl_sysctl;
static int wapbl_flush_disk_cache = 1;
static int wapbl_verbose_commit = 0;
+static int wapbl_allow_fuadpo = 0; /* switched off by default for now */
static inline size_t wapbl_space_free(size_t, off_t, off_t);
@@ -230,6 +231,16 @@
u_char *wl_buffer; /* l: buffer for wapbl_buffered_write() */
daddr_t wl_buffer_dblk; /* l: buffer disk block address */
size_t wl_buffer_used; /* l: buffer current use */
+
+ int wl_dkcache; /* r: disk cache flags */
+#define WAPBL_USE_FUA(wl) \
+ (wapbl_allow_fuadpo && ISSET((wl)->wl_dkcache, DKCACHE_FUA))
+#define WAPBL_JFLAGS(wl) \
+ (WAPBL_USE_FUA(wl) ? (wl)->wl_jwrite_flags : 0)
+#define WAPBL_MFLAGS(wl) \
+ (WAPBL_USE_FUA(wl) ? (wl)->wl_mwrite_flags : 0)
+ int wl_jwrite_flags; /* r: journal write flags */
+ int wl_mwrite_flags; /* r: metadata write flags */
};
#ifdef WAPBL_DEBUG_PRINT
@@ -281,6 +292,8 @@
static void wapbl_evcnt_init(struct wapbl *);
static void wapbl_evcnt_free(struct wapbl *);
+static void wapbl_dkcache_init(struct wapbl *);
+
#if 0
int wapbl_replay_verify(struct wapbl_replay *, struct vnode *);
#endif
@@ -335,6 +348,18 @@
SYSCTL_DESCR("show time and size of wapbl log commits"),
NULL, 0, &wapbl_verbose_commit, 0,
CTL_CREATE, CTL_EOL);
+ if (rv)
+ return rv;
+
+ rv = sysctl_createv(&wapbl_sysctl, 0, &rnode, &cnode,
+ CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
+ CTLTYPE_INT, "allow_fuadpo",
+ SYSCTL_DESCR("allow use of FUA/DPO instead of cash flush if available"),
+ NULL, 0, &wapbl_allow_fuadpo, 0,
+ CTL_CREATE, CTL_EOL);
+ if (rv)
+ return rv;
+
return rv;
}
@@ -391,6 +416,30 @@
evcnt_detach(&wl->wl_ev_cacheflush);
}
+static void
+wapbl_dkcache_init(struct wapbl *wl)
+{
+ int error;
+
+ /* Get disk cache flags */
+ error = VOP_IOCTL(wl->wl_devvp, DIOCGCACHE, &wl->wl_dkcache,
+ FWRITE, FSCRED);
+ if (error) {
+ /* behave as if there was a write cache */
+ wl->wl_dkcache = DKCACHE_WRITE;
+ }
+
+ /* Use FUA instead of cache flush if available */
+ if (ISSET(wl->wl_dkcache, DKCACHE_FUA)) {
+ wl->wl_jwrite_flags |= B_MEDIA_FUA;
+ wl->wl_mwrite_flags |= B_MEDIA_FUA;
+ }
+
+ /* Use DPO for journal writes if available */
+ if (ISSET(wl->wl_dkcache, DKCACHE_DPO))
+ wl->wl_jwrite_flags |= B_MEDIA_DPO;
+}
+
static int
wapbl_start_flush_inodes(struct wapbl *wl, struct wapbl_replay *wr)
{
@@ -563,6 +612,8 @@
wapbl_evcnt_init(wl);
+ wapbl_dkcache_init(wl);
+
/* Initialize the commit header */
{
struct wapbl_wc_header *wc;
@@ -809,7 +860,6 @@
struct buf *bp;
int error;
- KASSERT((flags & ~(B_WRITE | B_READ)) == 0);
KASSERT(devvp->v_type == VBLK);
if ((flags & (B_WRITE | B_READ)) == B_WRITE) {
@@ -823,7 +873,7 @@
bp = getiobuf(devvp, true);
bp->b_flags = flags;
- bp->b_cflags = BC_BUSY; /* silly & dubious */
+ bp->b_cflags = BC_BUSY; /* mandatory, asserted by biowait() */
bp->b_dev = devvp->v_rdev;
bp->b_data = data;
bp->b_bufsize = bp->b_resid = bp->b_bcount = len;
@@ -898,7 +948,8 @@
return 0;
error = wapbl_doio(wl->wl_buffer, wl->wl_buffer_used,
- wl->wl_devvp, wl->wl_buffer_dblk, B_WRITE);
+ wl->wl_devvp, wl->wl_buffer_dblk,
+ B_WRITE | WAPBL_JFLAGS(wl));
wl->wl_buffer_used = 0;
wl->wl_ev_journalwrite.ev_count++;
@@ -948,12 +999,10 @@
if (len >= resid) {
memcpy(wl->wl_buffer + wl->wl_buffer_used, data, resid);
wl->wl_buffer_used += resid;
- error = wapbl_doio(wl->wl_buffer, wl->wl_buffer_used,
- wl->wl_devvp, wl->wl_buffer_dblk, B_WRITE);
+ error = wapbl_buffered_flush(wl);
data = (uint8_t *)data + resid;
len -= resid;
wl->wl_buffer_dblk = pbn + btodb(resid);
- wl->wl_buffer_used = 0;
if (error)
return error;
}
@@ -1500,6 +1549,13 @@
}
/*
+ * Make sure that the buf doesn't retain the media flags, so that
+ * e.g. wapbl_allow_fuadpo has immediate effect on any following I/O.
+ * The flags will be set again if needed by another I/O.
+ */
+ bp->b_flags &= ~B_MEDIA_FLAGS;
+
+ /*
* Release the buffer here. wapbl_flush() may wait for the
* log to become empty and we better unbusy the buffer before
* wapbl_flush() returns.
@@ -1754,6 +1810,10 @@
}
bp->b_iodone = wapbl_biodone;
bp->b_private = we;
+
+ /* make sure the block is saved sync when FUA in use */
+ bp->b_flags |= WAPBL_MFLAGS(wl);
+
bremfree(bp);
wapbl_remove_buf_locked(wl, bp);
mutex_exit(&wl->wl_mtx);
@@ -2201,7 +2261,8 @@
int force = 1;
int error;
- if (!wapbl_flush_disk_cache) {
+ /* Skip full cache sync if disabled, or when using FUA */
+ if (!wapbl_flush_disk_cache || WAPBL_USE_FUA(wl)) {
return 0;
}
if (verbose) {
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