The patch titled
Subject: readahead: simplify gotos in page_cache_sync_ra()
has been added to the -mm mm-unstable branch. Its filename is
readahead-simplify-gotos-in-page_cache_sync_ra.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/readahead-simplify-gotos-in-page_cache_sync_ra.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Jan Kara <jack@xxxxxxx>
Subject: readahead: simplify gotos in page_cache_sync_ra()
Date: Tue, 25 Jun 2024 12:19:00 +0200
Unify all conditions for initial readahead to simplify goto logic in
page_cache_sync_ra(). No functional changes.
Link: https://lkml.kernel.org/r/20240625101909.12234-10-jack@xxxxxxx
Signed-off-by: Jan Kara <jack@xxxxxxx>
Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/readahead.c | 26 +++++++++-----------------
1 file changed, 9 insertions(+), 17 deletions(-)
--- a/mm/readahead.c~readahead-simplify-gotos-in-page_cache_sync_ra
+++ a/mm/readahead.c
@@ -532,20 +532,19 @@ void page_cache_sync_ra(struct readahead
}
max_pages = ractl_max_pages(ractl, req_count);
+ prev_index = (unsigned long long)ra->prev_pos >> PAGE_SHIFT;
/*
- * start of file or oversized read
- */
- if (!index || req_count > max_pages)
- goto initial_readahead;
-
- /*
- * sequential cache miss
+ * A start of file, oversized read, or sequential cache miss:
* trivial case: (index - prev_index) == 1
* unaligned reads: (index - prev_index) == 0
*/
- prev_index = (unsigned long long)ra->prev_pos >> PAGE_SHIFT;
- if (index - prev_index <= 1UL)
- goto initial_readahead;
+ if (!index || req_count > max_pages || index - prev_index <= 1UL) {
+ ra->start = index;
+ ra->size = get_init_ra_size(req_count, max_pages);
+ ra->async_size = ra->size > req_count ? ra->size - req_count :
+ ra->size >> 1;
+ goto readit;
+ }
/*
* Query the page cache and look for the traces(cached history pages)
@@ -572,13 +571,6 @@ void page_cache_sync_ra(struct readahead
ra->start = index;
ra->size = min(contig_count + req_count, max_pages);
ra->async_size = 1;
- goto readit;
-
-initial_readahead:
- ra->start = index;
- ra->size = get_init_ra_size(req_count, max_pages);
- ra->async_size = ra->size > req_count ? ra->size - req_count :
- ra->size >> 1;
readit:
ractl->_index = ra->start;
page_cache_ra_order(ractl, ra, 0);
_
Patches currently in -mm which might be from jack@xxxxxxx are
revert-mm-writeback-fix-possible-divide-by-zero-in-wb_dirty_limits-again.patch
mm-avoid-overflows-in-dirty-throttling-logic.patch
readahead-make-sure-sync-readahead-reads-needed-page.patch
filemap-fix-page_cache_next_miss-when-no-hole-found.patch
readahead-properly-shorten-readahead-when-falling-back-to-do_page_cache_ra.patch
readahead-drop-pointless-index-from-force_page_cache_ra.patch
readahead-drop-index-argument-of-page_cache_async_readahead.patch
readahead-drop-dead-code-in-page_cache_ra_order.patch
readahead-drop-dead-code-in-ondemand_readahead.patch
readahead-disentangle-async-and-sync-readahead.patch
readahead-fold-try_context_readahead-into-its-single-caller.patch
readahead-simplify-gotos-in-page_cache_sync_ra.patch
