Re: 2.2.2 two major problems

Andrea Arcangeli (andrea@e-mind.com)
Thu, 4 Mar 1999 01:27:08 +0100 (CET)


On Thu, 4 Mar 1999, Alan Cox wrote:

>> I think that replacing the if (toomany) wakeup_bdflush(0) with
>> wakeup_bdflush(1) would have fixed it everywhere. But we instead added
>
>Well its simple to analyse. Why not post a patch to the list for folks to
>beat on ?

The instructions to patch by hand were just been present on the list (not
really in form of a patch). They are been proposed by sct in first place
if I remeber well.

but OK here is a patch:

Index: buffer.c
===================================================================
RCS file: /var/cvs/linux/fs/buffer.c,v
retrieving revision 1.1.2.22
diff -u -r1.1.2.22 buffer.c
--- buffer.c 1999/02/20 15:57:29 1.1.2.22
+++ linux/fs/buffer.c 1999/03/04 00:24:33
@@ -78,7 +78,6 @@

static int nr_buffers = 0;
static int nr_buffers_type[NR_LIST] = {0,};
-static int size_buffers_type[NR_LIST] = {0,};
static int nr_buffer_heads = 0;
static int nr_unused_buffer_heads = 0;

@@ -104,8 +103,7 @@
each time we call refill */
int nref_dirt; /* Dirty buffer threshold for activating bdflush
when trying to refill buffers. */
- int pct_dirt; /* Max %age of mem for dirty buffers before
- activating bdflush */
+ int dummy1; /* unused */
int age_buffer; /* Time for normal buffer to age before
we flush it */
int age_super; /* Time for superblock to age before we
@@ -486,7 +484,6 @@
return;
}
nr_buffers_type[bh->b_list]--;
- size_buffers_type[bh->b_list] -= bh->b_size;
remove_from_hash_queue(bh);
remove_from_lru_list(bh);
}
@@ -560,7 +557,6 @@
(*bhp)->b_prev_free = bh;

nr_buffers_type[bh->b_list]++;
- size_buffers_type[bh->b_list] += bh->b_size;

/* Put the buffer in new hash-queue if it has a device. */
bh->b_next = NULL;
@@ -814,19 +810,13 @@
file_buffer(buf, dispose);
if(dispose == BUF_DIRTY) {
int too_many = (nr_buffers * bdf_prm.b_un.nfract/100);
- int too_large = (num_physpages * bdf_prm.b_un.pct_dirt/100);

/* This buffer is dirty, maybe we need to start flushing.
* If too high a percentage of the buffers are dirty...
*/
- if (nr_buffers_type[BUF_DIRTY] > too_many ||
- size_buffers_type[BUF_DIRTY]/PAGE_SIZE > too_large) {
- if (nr_buffers_type[BUF_LOCKED] > 3 * bdf_prm.b_un.ndirty)
- wakeup_bdflush(1);
- else
- wakeup_bdflush(0);
- }
-
+ if (nr_buffers_type[BUF_DIRTY] > too_many)
+ wakeup_bdflush(1);
+
/* If this is a loop device, and
* more than half of the buffers are dirty...
* (Prevents no-free-buffers deadlock with loop device.)

Andrea Arcangeli

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