From: Baoquan He <bhe@redhat.com>
To: Uladzislau Rezki <urezki@gmail.com>
Cc: rulinhuang <rulin.huang@intel.com>,
akpm@linux-foundation.org, colin.king@intel.com,
hch@infradead.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, lstoakes@gmail.com, tianyou.li@intel.com,
tim.c.chen@intel.com, wangyang.guo@intel.com,
zhiguo.zhou@intel.com
Subject: Re: [PATCH v7 1/2] mm/vmalloc: Moved macros with no functional change happened
Date: Thu, 7 Mar 2024 09:23:10 +0800 [thread overview]
Message-ID: <ZekW/nGXfTqOlvPZ@MiWiFi-R3L-srv> (raw)
In-Reply-To: <Zei9n-VMxtzG8z4Y@pc636>
On 03/06/24 at 08:01pm, Uladzislau Rezki wrote:
> On Fri, Mar 01, 2024 at 10:54:16AM -0500, rulinhuang wrote:
......
>
> Sorry for the late answer, i also just noticed this email. It was not in
> my inbox...
>
> OK, now you move part of the per-cpu allocator on the top and leave
> another part down making it split. This is just for the:
>
> BUG_ON(va_flags & VMAP_RAM);
>
> VMAP_RAM macro. Do we really need this BUG_ON()?
Sorry, I suggested that when reviewing v5:
https://lore.kernel.org/all/ZdiltpK5fUvwVWtD@MiWiFi-R3L-srv/T/#u
About part of per-cpu kva allocator moving and the split making, I would
argue that we will have vmap_nodes defintion and basic helper functions
like addr_to_node_id() etc at top, and leave other part like
size_to_va_pool(), node_pool_add_va() etc down. These are similar.
While about whether we should add 'BUG_ON(va_flags & VMAP_RAM);', I am
not sure about it. When I suggested that, I am also hesitant. From the
current code, alloc_vmap_area() is called in below three functions, only
__get_vm_area_node() will pass the non-NULL vm.
new_vmap_block() -|
vm_map_ram() ----> alloc_vmap_area()
__get_vm_area_node() -|
It could be wrongly passed in the future? Only checking if vm is
non-NULL makes me feel a little unsafe. While I am fine if removing the
BUG_ON, because there's no worry in the current code. We can wait and
see in the future.
if (vm) {
BUG_ON(va_flags & VMAP_RAM);
setup_vmalloc_vm(vm, va, flags, caller);
}
Thanks
Baoquan
next prev parent reply other threads:[~2024-03-07 1:23 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-01 15:54 [PATCH v7 0/2] mm/vmalloc: lock contention optimization under multi-threading rulinhuang
2024-03-01 15:54 ` [PATCH v7 1/2] mm/vmalloc: Moved macros with no functional change happened rulinhuang
2024-03-06 13:23 ` Baoquan He
2024-03-06 19:01 ` Uladzislau Rezki
2024-03-07 1:23 ` Baoquan He [this message]
2024-03-07 3:01 ` Huang, Rulin
2024-03-07 3:32 ` Baoquan He
2024-03-07 5:48 ` Huang, Rulin
2024-03-07 19:53 ` Uladzislau Rezki
2024-03-07 19:16 ` Uladzislau Rezki
2024-03-08 8:23 ` Baoquan He
2024-03-08 10:28 ` Uladzislau Rezki
2024-03-09 4:54 ` Baoquan He
2024-03-01 15:54 ` [PATCH v7 2/2] mm/vmalloc: Eliminated the lock contention from twice to once rulinhuang
2024-03-06 13:55 ` Baoquan He
2024-03-06 9:18 ` [PATCH v7 0/2] mm/vmalloc: lock contention optimization under multi-threading Huang, Rulin
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