From: Uladzislau Rezki <urezki@gmail.com>
To: Chen Wandun <chenwandun@huawei.com>
Cc: akpm@linux-foundation.org, npiggin@gmail.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, edumazet@google.com,
wangkefeng.wang@huawei.com, guohanjun@huawei.com
Subject: Re: [PATCH] mm/vmalloc: fix numa spreading for large hash tables
Date: Thu, 14 Oct 2021 12:01:57 +0200 [thread overview]
Message-ID: <20211014100157.GA1844@pc638.lan> (raw)
In-Reply-To: <20210928121040.2547407-1-chenwandun@huawei.com>
On Tue, Sep 28, 2021 at 08:10:40PM +0800, Chen Wandun wrote:
> Eric Dumazet reported a strange numa spreading info in [1], and found
> commit 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings") introduced
> this issue [2].
>
> Dig into the difference before and after this patch, page allocation has
> some difference:
>
> before:
> alloc_large_system_hash
> __vmalloc
> __vmalloc_node(..., NUMA_NO_NODE, ...)
> __vmalloc_node_range
> __vmalloc_area_node
> alloc_page /* because NUMA_NO_NODE, so choose alloc_page branch */
> alloc_pages_current
> alloc_page_interleave /* can be proved by print policy mode */
>
> after:
> alloc_large_system_hash
> __vmalloc
> __vmalloc_node(..., NUMA_NO_NODE, ...)
> __vmalloc_node_range
> __vmalloc_area_node
> alloc_pages_node /* choose nid by nuam_mem_id() */
> __alloc_pages_node(nid, ....)
>
> So after commit 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings"),
> it will allocate memory in current node instead of interleaving allocate
> memory.
>
> [1]
> https://lore.kernel.org/linux-mm/CANn89iL6AAyWhfxdHO+jaT075iOa3XcYn9k6JJc7JR2XYn6k_Q@mail.gmail.com/
>
> [2]
> https://lore.kernel.org/linux-mm/CANn89iLofTR=AK-QOZY87RdUZENCZUT4O6a0hvhu3_EwRMerOg@mail.gmail.com/
>
> Fixes: 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings")
> Reported-by: Eric Dumazet <edumazet@google.com>
> Signed-off-by: Chen Wandun <chenwandun@huawei.com>
> ---
> mm/vmalloc.c | 33 ++++++++++++++++++++++++++-------
> 1 file changed, 26 insertions(+), 7 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index f884706c5280..48e717626e94 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2823,6 +2823,8 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
> unsigned int order, unsigned int nr_pages, struct page **pages)
> {
> unsigned int nr_allocated = 0;
> + struct page *page;
> + int i;
>
> /*
> * For order-0 pages we make use of bulk allocator, if
> @@ -2833,6 +2835,7 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
> if (!order) {
> while (nr_allocated < nr_pages) {
> unsigned int nr, nr_pages_request;
> + page = NULL;
>
> /*
> * A maximum allowed request is hard-coded and is 100
> @@ -2842,9 +2845,23 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
> */
> nr_pages_request = min(100U, nr_pages - nr_allocated);
>
> - nr = alloc_pages_bulk_array_node(gfp, nid,
> - nr_pages_request, pages + nr_allocated);
> -
> + if (nid == NUMA_NO_NODE) {
>
<snip>
void *vmalloc(unsigned long size)
{
return __vmalloc_node(size, 1, GFP_KERNEL, NUMA_NO_NODE,
__builtin_return_address(0));
}
EXPORT_SYMBOL(vmalloc);
<snip>
vmalloc() uses NUMA_NO_NODE, so all vmalloc calls will be reverted to a single
page allocator for NUMA and non-NUMA systems. Is it intentional to bypass the
optimized bulk allocator for non-NUMA systems?
Thanks!
--
Vlad Rezki
next prev parent reply other threads:[~2021-10-14 10:02 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-28 12:10 [PATCH] mm/vmalloc: fix numa spreading for large hash tables Chen Wandun
2021-09-28 22:33 ` Andrew Morton
2021-10-14 8:50 ` Chen Wandun
2021-10-13 21:46 ` Shakeel Butt
2021-10-14 8:59 ` Chen Wandun
2021-10-15 1:34 ` Nicholas Piggin
2021-10-15 2:31 ` Chen Wandun
2021-10-15 7:11 ` Nicholas Piggin
2021-10-15 11:51 ` Eric Dumazet
2021-10-18 8:45 ` Chen Wandun
2021-10-16 16:46 ` Uladzislau Rezki
2021-10-14 9:29 ` [PATCH] mm/vmalloc: introduce alloc_pages_bulk_array_mempolicy to accelerate memory allocation Chen Wandun
2021-10-15 21:13 ` Andrew Morton
2021-10-16 16:27 ` Uladzislau Rezki
2021-10-14 10:01 ` Uladzislau Rezki [this message]
2021-10-15 2:20 ` [PATCH] mm/vmalloc: fix numa spreading for large hash tables Chen Wandun
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