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From: Oscar Salvador <osalvador@suse.de>
To: Mike Rapoport <rppt@kernel.org>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
	David Hildenbrand <david@redhat.com>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	linux-arm-kernel@lists.infradead.org, linux-kernel@vger.org
Subject: Re: [PATCH] mm/memory_hotplug: Drop memblock_phys_free() call in try_remove_memory()
Date: Mon, 10 Jun 2024 06:56:15 +0200	[thread overview]
Message-ID: <ZmaHbzIT8yWR_g5d@localhost.localdomain> (raw)
In-Reply-To: <20240605082049.973242-1-rppt@kernel.org>

On Wed, Jun 05, 2024 at 11:20:49AM +0300, Mike Rapoport wrote:
> From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> 
> The call for memblock_phys_free() in try_remove_memory() does not balance
> any call to memblock_alloc() (or memblock_reserve() for that matter).
> 
> There are no memblock_reserve() calls in mm/memory_hotplug.c, no memblock
> allocations possible after mm_core_init(), and even if memblock_add_node()
> called from add_memory_resource() would need to allocate memory, that
> memory would ba allocated from slab.
> 
> The patch f9126ab9241f ("memory-hotplug: fix wrong edge when hot add a new
> node") that introduced that call to memblock_free() does not provide
> adequate description why that was required and tinkering with memblock in
> the context of memory hotplug on x86 seems bogus because x86 never kept
> memblock after boot anyway.
> 
> Drop memblock_phys_free() call in try_remove_memory().
> 
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> [rppt: rewrite the commit message]
> Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>

Acked-by: Oscar Salvador <osalvador@suse.de>

> ---
>  mm/memory_hotplug.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 431b1f6753c0..e0d49f128e0d 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -2283,10 +2283,8 @@ static int __ref try_remove_memory(u64 start, u64 size)
>  		remove_memory_blocks_and_altmaps(start, size);
>  	}
>  
> -	if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
> -		memblock_phys_free(start, size);
> +	if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
>  		memblock_remove(start, size);
> -	}
>  
>  	release_mem_region_adjustable(start, size);
>  
> -- 
> 2.43.0
> 

-- 
Oscar Salvador
SUSE Labs

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WARNING: multiple messages have this Message-ID (diff)
From: Oscar Salvador <osalvador@suse.de>
To: Mike Rapoport <rppt@kernel.org>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
	David Hildenbrand <david@redhat.com>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	linux-arm-kernel@lists.infradead.org, linux-kernel@vger.org
Subject: Re: [PATCH] mm/memory_hotplug: Drop memblock_phys_free() call in try_remove_memory()
Date: Mon, 10 Jun 2024 06:56:15 +0200	[thread overview]
Message-ID: <ZmaHbzIT8yWR_g5d@localhost.localdomain> (raw)
In-Reply-To: <20240605082049.973242-1-rppt@kernel.org>

On Wed, Jun 05, 2024 at 11:20:49AM +0300, Mike Rapoport wrote:
> From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> 
> The call for memblock_phys_free() in try_remove_memory() does not balance
> any call to memblock_alloc() (or memblock_reserve() for that matter).
> 
> There are no memblock_reserve() calls in mm/memory_hotplug.c, no memblock
> allocations possible after mm_core_init(), and even if memblock_add_node()
> called from add_memory_resource() would need to allocate memory, that
> memory would ba allocated from slab.
> 
> The patch f9126ab9241f ("memory-hotplug: fix wrong edge when hot add a new
> node") that introduced that call to memblock_free() does not provide
> adequate description why that was required and tinkering with memblock in
> the context of memory hotplug on x86 seems bogus because x86 never kept
> memblock after boot anyway.
> 
> Drop memblock_phys_free() call in try_remove_memory().
> 
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> [rppt: rewrite the commit message]
> Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>

Acked-by: Oscar Salvador <osalvador@suse.de>

> ---
>  mm/memory_hotplug.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 431b1f6753c0..e0d49f128e0d 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -2283,10 +2283,8 @@ static int __ref try_remove_memory(u64 start, u64 size)
>  		remove_memory_blocks_and_altmaps(start, size);
>  	}
>  
> -	if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
> -		memblock_phys_free(start, size);
> +	if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
>  		memblock_remove(start, size);
> -	}
>  
>  	release_mem_region_adjustable(start, size);
>  
> -- 
> 2.43.0
> 

-- 
Oscar Salvador
SUSE Labs


  parent reply	other threads:[~2024-06-10  4:56 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-06-05  8:20 [PATCH] mm/memory_hotplug: Drop memblock_phys_free() call in try_remove_memory() Mike Rapoport
2024-06-05  8:20 ` Mike Rapoport
2024-06-05 13:29 ` David Hildenbrand
2024-06-07  7:37 ` Oscar Salvador
2024-06-07  7:37   ` Oscar Salvador
2024-06-10  4:56 ` Oscar Salvador [this message]
2024-06-10  4:56   ` Oscar Salvador

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