+ mm-vmalloc-do-not-output-a-spurious-warning-when-huge-vmalloc-fails.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/vmalloc: do not output a spurious warning when huge vmalloc() fails
has been added to the -mm mm-unstable branch.  Its filename is
     mm-vmalloc-do-not-output-a-spurious-warning-when-huge-vmalloc-fails.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmalloc-do-not-output-a-spurious-warning-when-huge-vmalloc-fails.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: Lorenzo Stoakes <lstoakes@gmail.com>
Subject: mm/vmalloc: do not output a spurious warning when huge vmalloc() fails
Date: Mon, 5 Jun 2023 21:11:07 +0100

In __vmalloc_area_node() we always warn_alloc() when an allocation
performed by vm_area_alloc_pages() fails unless it was due to a pending
fatal signal.

However, huge page allocations instigated either by vmalloc_huge() or
__vmalloc_node_range() (or a caller that invokes this like kvmalloc() or
kvmalloc_node()) always falls back to order-0 allocations if the huge page
allocation fails.

This renders the warning useless and noisy, especially as all callers
appear to be aware that this may fallback.  This has already resulted in
at least one bug report from a user who was confused by this (see link).

Therefore, simply update the code to only output this warning for order-0
pages when no fatal signal is pending.

Link: https://bugzilla.suse.com/show_bug.cgi?id=1211410
Link: https://lkml.kernel.org/r/20230605201107.83298-1-lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vmalloc.c |   17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

--- a/mm/vmalloc.c~mm-vmalloc-do-not-output-a-spurious-warning-when-huge-vmalloc-fails
+++ a/mm/vmalloc.c
@@ -3149,11 +3149,20 @@ static void *__vmalloc_area_node(struct
 	 * allocation request, free them via vfree() if any.
 	 */
 	if (area->nr_pages != nr_small_pages) {
-		/* vm_area_alloc_pages() can also fail due to a fatal signal */
-		if (!fatal_signal_pending(current))
+		/*
+		 * vm_area_alloc_pages() can fail due to insufficient memory but
+		 * also:-
+		 *
+		 * - a pending fatal signal
+		 * - insufficient huge page-order pages
+		 *
+		 * Since we always retry allocations at order-0 in the huge page
+		 * case a warning for either is spurious.
+		 */
+		if (!fatal_signal_pending(current) && page_order == 0)
 			warn_alloc(gfp_mask, NULL,
-				"vmalloc error: size %lu, page order %u, failed to allocate pages",
-				area->nr_pages * PAGE_SIZE, page_order);
+				"vmalloc error: size %lu, failed to allocate pages",
+				area->nr_pages * PAGE_SIZE);
 		goto fail;
 	}
 
_

Patches currently in -mm which might be from lstoakes@gmail.com are

lib-test_vmallocc-avoid-garbage-in-page-array.patch
mm-mmap-separate-writenotify-and-dirty-tracking-logic.patch
mm-gup-disallow-foll_longterm-gup-nonfast-writing-to-file-backed-mappings.patch
mm-gup-disallow-foll_longterm-gup-fast-writing-to-file-backed-mappings.patch
mm-gup-add-missing-gup_must_unshare-check-to-gup_huge_pgd.patch
mm-gup-remove-unused-vmas-parameter-from-get_user_pages.patch
mm-gup-remove-unused-vmas-parameter-from-pin_user_pages_remote.patch
mm-gup-remove-vmas-parameter-from-get_user_pages_remote.patch
io_uring-rsrc-delegate-vma-file-backed-check-to-gup.patch
mm-gup-remove-vmas-parameter-from-pin_user_pages.patch
mm-gup-remove-vmas-array-from-internal-gup-functions.patch
mm-mmap-refactor-mlock_future_check.patch
mm-vmalloc-dont-purge-usable-blocks-unnecessarily-fix.patch
mm-vmalloc-do-not-output-a-spurious-warning-when-huge-vmalloc-fails.patch