The quilt patch titled
Subject: readahead: use ilog2 instead of a while loop in page_cache_ra_order()
has been removed from the -mm tree. Its filename was
readahead-use-ilog2-instead-of-a-while-loop-in-page_cache_ra_order.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
Subject: readahead: use ilog2 instead of a while loop in page_cache_ra_order()
Date: Mon, 15 Jan 2024 11:25:22 +0100
A while loop is used to adjust the new_order to be lower than the
ra->size. ilog2 could be used to do the same instead of using a loop.
ilog2 typically resolves to a bit scan reverse instruction. This is
particularly useful when ra->size is smaller than the 2^new_order as it
resolves in one instruction instead of looping to find the new_order.
No functional changes.
Link: https://lkml.kernel.org/r/20240115102523.2336742-1-kernel@xxxxxxxxxxxxxxxx
Signed-off-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/readahead.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
--- a/mm/readahead.c~readahead-use-ilog2-instead-of-a-while-loop-in-page_cache_ra_order
+++ a/mm/readahead.c
@@ -500,10 +500,8 @@ void page_cache_ra_order(struct readahea
if (new_order < MAX_PAGECACHE_ORDER) {
new_order += 2;
- if (new_order > MAX_PAGECACHE_ORDER)
- new_order = MAX_PAGECACHE_ORDER;
- while ((1 << new_order) > ra->size)
- new_order--;
+ new_order = min_t(unsigned int, MAX_PAGECACHE_ORDER, new_order);
+ new_order = min_t(unsigned int, new_order, ilog2(ra->size));
}
filemap_invalidate_lock_shared(mapping);
_
Patches currently in -mm which might be from p.raghav@xxxxxxxxxxx are
