+ mm-filemap-do-not-count-fault_flag_tried-retries-as-mmap-hits.patch added to mm-new branch

+ mm-filemap-do-not-count-fault_flag_tried-retries-as-mmap-hits.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm/filemap: do not count FAULT_FLAG_TRIED retries as mmap hits
has been added to the -mm mm-new branch.  Its filename is
     mm-filemap-do-not-count-fault_flag_tried-retries-as-mmap-hits.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-filemap-do-not-count-fault_flag_tried-retries-as-mmap-hits.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: fujunjie <fujunjie1@qq.com>
Subject: mm/filemap: do not count FAULT_FLAG_TRIED retries as mmap hits
Date: Tue, 28 Apr 2026 01:59:44 +0000

A fault that starts synchronous mmap readahead can return VM_FAULT_RETRY
after dropping mmap_lock.  The retry may then map the folio brought in by
that same miss.

Do not let this retry decrement mmap_miss.  The retry still maps the folio
from the page cache; it just does not count as a useful mmap readahead
hit.

Link: https://lore.kernel.org/tencent_22E6B8849EC1141FE7773C64467E6F1E2C09@qq.com
Signed-off-by: fujunjie <fujunjie1@qq.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/filemap.c |    1 +
 1 file changed, 1 insertion(+)

--- a/mm/filemap.c~mm-filemap-do-not-count-fault_flag_tried-retries-as-mmap-hits
+++ a/mm/filemap.c
@@ -3937,6 +3937,7 @@ vm_fault_t filemap_map_pages(struct vm_f
 		 * we can stop read-ahead.
 		 */
 		if ((map_ret & VM_FAULT_NOPAGE) &&
+		    !(vmf->flags & FAULT_FLAG_TRIED) &&
 		    !folio_test_workingset(folio)) {
 			unsigned short mmap_miss;
 
_

Patches currently in -mm which might be from fujunjie1@qq.com are

mm-madvise-reject-invalid-process_madvise-advice-for-zero-length-vectors.patch
mm-filemap-count-only-the-faulting-address-as-a-mmap-hit.patch
mm-filemap-do-not-count-fault_flag_tried-retries-as-mmap-hits.patch