From: Andrew Morton <akpm@zip.com.au>
To: "Van Maren, Kevin" <kevin.vanmaren@unisys.com>
Cc: "'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>
Subject: Re: The cause of the "VM" performance problem with 2.4.X
Date: Thu, 23 Aug 2001 10:18:05 -0700 [thread overview]
Message-ID: <3B853ACD.5A17AB9F@zip.com.au> (raw)
In-Reply-To: <245F259ABD41D511A07000D0B71C4CBA289F34@us-slc-exch-3.slc.unisys.com>
"Van Maren, Kevin" wrote:
>
> It looks like the same patch as yesterday. Did you attach the wrong
> patch?
Drat, sorry - it's on the other machine. Here's a reconstruction:
--- linux-2.4.9/fs/buffer.c Thu Aug 16 12:23:19 2001
+++ linux-akpm/fs/buffer.c Thu Aug 23 10:15:41 2001
@@ -199,7 +199,7 @@ static void write_locked_buffers(struct
* return without it!
*/
#define NRSYNC (32)
-static int write_some_buffers(kdev_t dev)
+static int write_some_buffers(kdev_t dev, struct buffer_head **start_bh)
{
struct buffer_head *next;
struct buffer_head *array[NRSYNC];
@@ -207,6 +207,12 @@ static int write_some_buffers(kdev_t dev
int nr;
next = lru_list[BUF_DIRTY];
+ if (start_bh && *start_bh) {
+ if ((*start_bh)->b_list == BUF_DIRTY)
+ next = *start_bh;
+ brelse(*start_bh);
+ *start_bh = NULL;
+ }
nr = nr_buffers_type[BUF_DIRTY] * 2;
count = 0;
while (next && --nr >= 0) {
@@ -215,8 +221,11 @@ static int write_some_buffers(kdev_t dev
if (dev && bh->b_dev != dev)
continue;
- if (test_and_set_bit(BH_Lock, &bh->b_state))
+ if (test_and_set_bit(BH_Lock, &bh->b_state)) {
+ /* Shouldn't be on BUF_DIRTY */
+ __refile_buffer(bh);
continue;
+ }
if (atomic_set_buffer_clean(bh)) {
__refile_buffer(bh);
get_bh(bh);
@@ -224,6 +233,10 @@ static int write_some_buffers(kdev_t dev
if (count < NRSYNC)
continue;
+ if (start_bh && next) {
+ get_bh(next);
+ *start_bh = next;
+ }
spin_unlock(&lru_list_lock);
write_locked_buffers(array, count);
return -EAGAIN;
@@ -243,9 +256,11 @@ static int write_some_buffers(kdev_t dev
*/
static void write_unlocked_buffers(kdev_t dev)
{
+ struct buffer_head *start_bh = NULL;
do {
spin_lock(&lru_list_lock);
- } while (write_some_buffers(dev));
+ } while (write_some_buffers(dev, &start_bh));
+ brelse(start_bh);
run_task_queue(&tq_disk);
}
@@ -1116,14 +1131,14 @@ int balance_dirty_state(kdev_t dev)
*/
void balance_dirty(kdev_t dev)
{
- int state = balance_dirty_state(dev);
+ int state = balance_dirty_state(NODEV);
if (state < 0)
return;
/* If we're getting into imbalance, start write-out */
spin_lock(&lru_list_lock);
- write_some_buffers(dev);
+ write_some_buffers(NODEV, NULL);
/*
* And if we're _really_ out of balance, wait for
@@ -1132,8 +1147,9 @@ void balance_dirty(kdev_t dev)
* This will throttle heavy writers.
*/
if (state > 0) {
- wait_for_some_buffers(dev);
+ write_some_buffers(dev, NULL);
wakeup_bdflush();
+ wait_for_some_buffers(dev);
}
}
@@ -2607,7 +2623,7 @@ static int sync_old_buffers(void)
bh = lru_list[BUF_DIRTY];
if (!bh || time_before(jiffies, bh->b_flushtime))
break;
- if (write_some_buffers(NODEV))
+ if (write_some_buffers(NODEV, NULL))
continue;
return 0;
}
@@ -2706,7 +2722,7 @@ int bdflush(void *startup)
CHECK_EMERGENCY_SYNC
spin_lock(&lru_list_lock);
- if (!write_some_buffers(NODEV) || balance_dirty_state(NODEV) < 0) {
+ if (!write_some_buffers(NODEV, NULL) || balance_dirty_state(NODEV) < 0) {
wait_for_some_buffers(NODEV);
interruptible_sleep_on(&bdflush_wait);
}
next prev parent reply other threads:[~2001-08-23 17:18 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-08-23 17:06 The cause of the "VM" performance problem with 2.4.X Van Maren, Kevin
2001-08-23 17:18 ` Andrew Morton [this message]
-- strict thread matches above, loose matches on Subject: below --
2001-08-28 17:35 Van Maren, Kevin
2001-08-28 18:52 ` Linus Torvalds
2001-08-28 19:29 ` André Dahlqvist
2001-08-29 13:49 ` Rik van Riel
2001-08-29 8:22 ` Jens Axboe
2001-08-29 8:25 ` Jens Axboe
2001-08-23 17:26 Van Maren, Kevin
2001-08-23 1:48 Van Maren, Kevin
2001-08-23 16:33 ` Andrew Morton
2001-08-22 22:23 Van Maren, Kevin
2001-08-22 5:31 Van Maren, Kevin
2001-08-22 20:19 ` Andrew Morton
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