[PATCH] loop 1/9 file use highmem

From: Hugh Dickins (hugh@veritas.com)
Date: Tue Jun 10 2003 - 10:30:06 EST

Here's the first of nine small patches to the loop driver,
mostly to reduce its pressure on zone normal when there's highmem.

I don't pretend these fix every loop hang I see and you not,
nor have I completed reinvestigating those against latest kernel.
These patches just remove what I hope we'll agree is silliness,
setting a base for further work.

(Some could conceivably make some loads worse: making better use of
highmem for data could in theory expose kmap deadlocks, I've never seen,
or permit so much more data in transit that mempool exhaustion wins:
if so, we fix those issues, rather than depending on mistakes.)

Based on 2.5.70-mm7. Aggregate diffstat is:

 drivers/block/loop.c | 71 +++++++++++++++++++++++++++------------------
 fs/bio.c | 79 ---------------------------------------------------
 include/linux/bio.h | 1
 include/linux/loop.h | 1
 4 files changed, 43 insertions(+), 109 deletions(-)

loop 1/9 file use highmem

When loop restricts underlying file's allocation mask to avoid
deadlock, it unintentionally masks out its highmem capability,
making failures at the underlying level much more likely.

--- 2.5.70-mm7/drivers/block/loop.c Mon Jun 9 10:14:55 2003
+++ loop1/drivers/block/loop.c Mon Jun 9 10:29:01 2003
@@ -714,7 +714,7 @@
                 goto out_putf;
         lo->old_gfp_mask = inode->i_mapping->gfp_mask;
- inode->i_mapping->gfp_mask = GFP_NOIO;
+ inode->i_mapping->gfp_mask &= ~(__GFP_IO|__GFP_FS);
         set_blocksize(bdev, lo_blocksize);

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This archive was generated by hypermail 2b29 : Sun Jun 15 2003 - 22:00:23 EST