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mm: huge_memory: don't force huge page alignment on 32 bit 

commit efa7df3e3b ("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@kernel.org/
[2] https://lore.kernel.org/linux-mm/CAJuCfpHXLdQy1a2B6xN2d7quTYwg2OoZseYPZTRpU0eHHKD-sQ@mail.gmail.com/

Link: https://lkml.kernel.org/r/20240118180505.2914778-1-shy828301@gmail.com
Fixes: efa7df3e3b ("mm: align larger anonymous mappings on THP boundaries")
Signed-off-by: Yang Shi <yang@os.amperecomputing.com>
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Reported-by: Suren Baghdasaryan <surenb@google.com>
Tested-by: Jiri Slaby <jirislaby@kernel.org>
Tested-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Christopher Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Yang Shi 2024-01-18 10:05:05 -08:00 committed by Andrew Morton
parent 67695f18d5
commit 4ef9ad19e1
1 changed files with 4 additions and 0 deletions
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4
mm/huge_memory.c
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@ -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_area(struct file *filp,
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;