[PATCH] count for buffer IO in page_launder()

From: Marcelo Tosatti (marcelo@conectiva.com.br)
Date: Tue Feb 27 2001 - 02:09:09 EST


Hi,

page_launder() is not counting direct ll_rw_block() IO correctly in the
flushed pages counter.

A page is only counted as flushed if it had its buffer_head's freed,
meaning that pages which have been queued but not freed are not counted.

The following patch against ac5 fixes the problem.

diff -Nur linux.orig/mm/vmscan.c linux/mm/vmscan.c
--- linux.orig/mm/vmscan.c Sat Feb 24 23:30:20 2001
+++ linux/mm/vmscan.c Mon Feb 26 05:45:08 2001
@@ -535,7 +535,7 @@
                  * buffer pages
                  */
                 if (page->buffers) {
- int wait, clearedbuf;
+ int wait;
                         /*
                          * Since we might be doing disk IO, we have to
                          * drop the spinlock and take an extra reference
@@ -554,7 +554,8 @@
                                 wait = 0; /* No IO */
 
                         /* Try to free the page buffers. */
- clearedbuf = try_to_free_buffers(page, wait);
+ if (try_to_free_buffers(page, wait))
+ flushed_pages++;
 
                         /*
                          * Re-take the spinlock. Note that we cannot
@@ -564,10 +565,8 @@
                         spin_lock(&pagemap_lru_lock);
 
                         /* The buffers were not freed. */
- if (!clearedbuf) {
+ if (page->buffers) {
                                 add_page_to_inactive_dirty_list(page);
- if (wait)
- flushed_pages++;
 
                         /* The page was only in the buffer cache. */
                         } else if (!page->mapping) {
diff -Nur linux.orig/fs/buffer.c linux/fs/buffer.c
--- linux.orig/fs/buffer.c Sat Feb 24 23:30:16 2001
+++ linux/fs/buffer.c Mon Feb 26 04:44:54 2001
@@ -1399,7 +1399,8 @@
          * instead.
          */
         if (!offset) {
- if (!try_to_free_buffers(page, 0)) {
+ try_to_free_buffers(page, 0)
+ if (page->buffers) {
                         atomic_inc(&buffermem_pages);
                         return 0;
                 }
@@ -2413,7 +2414,7 @@
         spin_unlock(&free_list[index].lock);
         write_unlock(&hash_table_lock);
         spin_unlock(&lru_list_lock);
- return 1;
+ return 0;
 
 busy_buffer_page:
         /* Uhhuh, start writeback so that we don't end up with all dirty pages */
@@ -2428,6 +2429,7 @@
                         goto cleaned_buffers_try_again;
                 }
                 wakeup_bdflush(0);
+ return 1;
         }
         return 0;
 }

-
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This archive was generated by hypermail 2b29 : Wed Feb 28 2001 - 21:00:13 EST