The patch titled
Subject: mm/memory-failure: stop setting the folio error flag
has been added to the -mm mm-unstable branch. Its filename is
mm-memory-failure-stop-setting-the-folio-error-flag.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memory-failure-stop-setting-the-folio-error-flag.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: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm/memory-failure: stop setting the folio error flag
Date: Fri, 31 May 2024 04:29:25 +0100
Nobody checks the error flag any more, so setting it accomplishes nothing.
Remove the obsolete parts of this comment; it hasn't been true since
errseq_t was used to track writeback errors in 2017.
Link: https://lkml.kernel.org/r/20240531032938.2712870-1-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 29 -----------------------------
1 file changed, 29 deletions(-)
--- a/mm/memory-failure.c~mm-memory-failure-stop-setting-the-folio-error-flag
+++ a/mm/memory-failure.c
@@ -1112,7 +1112,6 @@ static int me_pagecache_dirty(struct pag
struct folio *folio = page_folio(p);
struct address_space *mapping = folio_mapping(folio);
- SetPageError(p);
/* TBD: print more information about the file. */
if (mapping) {
/*
@@ -1120,34 +1119,6 @@ static int me_pagecache_dirty(struct pag
* who check the mapping.
* This way the application knows that something went
* wrong with its dirty file data.
- *
- * There's one open issue:
- *
- * The EIO will be only reported on the next IO
- * operation and then cleared through the IO map.
- * Normally Linux has two mechanisms to pass IO error
- * first through the AS_EIO flag in the address space
- * and then through the PageError flag in the page.
- * Since we drop pages on memory failure handling the
- * only mechanism open to use is through AS_AIO.
- *
- * This has the disadvantage that it gets cleared on
- * the first operation that returns an error, while
- * the PageError bit is more sticky and only cleared
- * when the page is reread or dropped. If an
- * application assumes it will always get error on
- * fsync, but does other operations on the fd before
- * and the page is dropped between then the error
- * will not be properly reported.
- *
- * This can already happen even without hwpoisoned
- * pages: first on metadata IO errors (which only
- * report through AS_EIO) or when the page is dropped
- * at the wrong time.
- *
- * So right now we assume that the application DTRT on
- * the first EIO, but we're not worse than other parts
- * of the kernel.
*/
mapping_set_error(mapping, -EIO);
}
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-remove-page_mapping.patch
mm-memory-failure-stop-setting-the-folio-error-flag.patch
