From: Jiri Slaby <jirislaby@kernel.org>
To: Rik van Riel <riel@surriel.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team@fb.com, Matthew Wilcox <willy@infradead.org>,
Yang Shi <shy828301@gmail.com>, Christoph Lameter <cl@linux.com>
Subject: Re: [PATCH v2] mm: align larger anonymous mappings on THP boundaries
Date: Tue, 16 Jan 2024 12:53:06 +0100 [thread overview]
Message-ID: <d0a136a0-4a31-46bc-adf4-2db109a61672@kernel.org> (raw)
In-Reply-To: <20220809142457.4751229f@imladris.surriel.com>
Hi,
On 09. 08. 22, 20:24, Rik van Riel wrote:
> Align larger anonymous memory mappings on THP boundaries by
> going through thp_get_unmapped_area if THPs are enabled for
> the current process.
>
> With this patch, larger anonymous mappings are now THP aligned.
> When a malloc library allocates a 2MB or larger arena, that
> arena can now be mapped with THPs right from the start, which
> can result in better TLB hit rates and execution time.
This appears to break 32bit processes on x86_64 (at least). In
particular, 32bit kernel or firefox builds in our build system.
Reverting this on top of 6.7 makes it work again.
Downstream report:
https://bugzilla.suse.com/show_bug.cgi?id=1218841
So running:
pahole -J --btf_gen_floats -j --lang_exclude=rust
--skip_encoding_btf_inconsistent_proto --btf_gen_optimized .tmp_vmlinux.btf
crashes or errors out with some random errors:
[182671] STRUCT idr's field 'idr_next' offset=128 bit_size=0 type=181346
Error emitting field
strace shows mmap() fails with ENOMEM right before the errors:
1223 mmap2(NULL, 5783552, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0 <unfinished ...>
...
1223 <... mmap2 resumed>) = -1 ENOMEM (Cannot allocate memory)
Note the .tmp_vmlinux.btf above can be arbitrary, but likely large
enough. For reference, one is available at:
https://decibel.fi.muni.cz/~xslaby/n/btf
Any ideas?
> Signed-off-by: Rik van Riel <riel@surriel.com>
> ---
> v2: avoid the chicken & egg issue with MMF_VM_HUGEPAGE (Yang Shi)
>
> mm/mmap.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index c035020d0c89..1d859893436d 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -2229,6 +2229,9 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
> */
> pgoff = 0;
> get_area = shmem_get_unmapped_area;
> + } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
> + /* Ensures that larger anonymous mappings are THP aligned. */
> + get_area = thp_get_unmapped_area;
> }
>
> addr = get_area(file, addr, len, pgoff, flags);
thanks,
--
js
suse labs
next prev parent reply other threads:[~2024-01-16 11:53 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-09 18:24 [PATCH v2] mm: align larger anonymous mappings on THP boundaries Rik van Riel
2022-08-10 17:06 ` Yang Shi
2024-01-16 11:53 ` Jiri Slaby [this message]
2024-01-16 12:09 ` Jiri Slaby
2024-01-16 19:16 ` Suren Baghdasaryan
2024-01-16 20:56 ` Yang Shi
2024-01-16 21:57 ` Suren Baghdasaryan
2024-01-16 22:25 ` Yang Shi
2024-01-16 22:30 ` Suren Baghdasaryan
2024-01-16 23:14 ` Yang Shi
2024-01-17 17:40 ` Kees Cook
2024-01-17 23:32 ` Yang Shi
2024-01-18 0:01 ` Suren Baghdasaryan
2024-01-18 0:13 ` Yang Shi
2024-01-18 0:29 ` Suren Baghdasaryan
2024-01-18 1:34 ` Suren Baghdasaryan
2024-01-18 2:10 ` Suren Baghdasaryan
2024-01-16 20:55 ` Yang Shi
2024-01-18 0:07 ` Yang Shi
2024-01-18 0:09 ` Suren Baghdasaryan
2024-01-18 0:11 ` Suren Baghdasaryan
2024-01-18 0:15 ` Yang Shi
2024-01-18 0:28 ` Suren Baghdasaryan
2024-01-18 7:04 ` Jiri Slaby
2024-01-18 17:48 ` Suren Baghdasaryan
2024-01-18 18:42 ` Yang Shi
2024-01-18 18:42 ` Yang Shi
2024-01-20 13:43 ` Linux regression tracking #adding (Thorsten Leemhuis)
2024-01-20 15:47 ` Linux regression tracking #adding (Thorsten Leemhuis)
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