The patch titled
Subject: mm: huge_memory: don't force huge page alignment on 32 bit
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-huge_memory-dont-force-huge-page-alignment-on-32-bit.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-huge_memory-dont-force-huge-page-alignment-on-32-bit.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Yang Shi <yang@xxxxxxxxxxxxxxxxxxxxxx>
Subject: mm: huge_memory: don't force huge page alignment on 32 bit
Date: Thu, 18 Jan 2024 10:05:05 -0800
commit efa7df3e3bb5 ("mm: align larger anonymous mappings on THP
boundaries") caused two issues [1] [2] reported on 32 bit system or compat
userspace.
It doesn't make too much sense to force huge page alignment on 32 bit
system due to the constrained virtual address space.
[1] https://lore.kernel.org/linux-mm/d0a136a0-4a31-46bc-adf4-2db109a61672@xxxxxxxxxx/
[2] https://lore.kernel.org/linux-mm/CAJuCfpHXLdQy1a2B6xN2d7quTYwg2OoZseYPZTRpU0eHHKD-sQ@xxxxxxxxxxxxxx/
Link: https://lkml.kernel.org/r/20240118180505.2914778-1-shy828301@xxxxxxxxx
Fixes: efa7df3e3bb5 ("mm: align larger anonymous mappings on THP boundaries")
Signed-off-by: Yang Shi <yang@xxxxxxxxxxxxxxxxxxxxxx>
Reported-by: Jiri Slaby <jirislaby@xxxxxxxxxx>
Reported-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Tested-by: Jiri Slaby <jirislaby@xxxxxxxxxx>
Tested-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Christopher Lameter <cl@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/mm/huge_memory.c~mm-huge_memory-dont-force-huge-page-alignment-on-32-bit
+++ a/mm/huge_memory.c
@@ -37,6 +37,7 @@
#include <linux/page_owner.h>
#include <linux/sched/sysctl.h>
#include <linux/memory-tiers.h>
+#include <linux/compat.h>
#include <asm/tlb.h>
#include <asm/pgalloc.h>
@@ -811,6 +812,9 @@ static unsigned long __thp_get_unmapped_
loff_t off_align = round_up(off, size);
unsigned long len_pad, ret;
+ if (IS_ENABLED(CONFIG_32BIT) || in_compat_syscall())
+ return 0;
+
if (off_end <= off_align || (off_end - off_align) < size)
return 0;
_
Patches currently in -mm which might be from yang@xxxxxxxxxxxxxxxxxxxxxx are
mm-mmap-map-map_stack-to-vm_nohugepage.patch
mm-huge_memory-dont-force-huge-page-alignment-on-32-bit.patch
mm-mmap-no-need-to-call-khugepaged_enter_vma-for-stack.patch
