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Message-ID: <CAJZ5v0gDDEvBrNCbB8E3Stq4QE_+6X72Pbu0Wyj8bQoSPXs3WA@mail.gmail.com>
Date: Tue, 18 Sep 2018 23:18:41 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: David Hildenbrand <david@...hat.com>
Cc: Linux Memory Management List <linux-mm@...ck.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
"open list:DOCUMENTATION" <linux-doc@...r.kernel.org>,
linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
xen-devel@...ts.xenproject.org, devel@...uxdriverproject.org,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Len Brown <lenb@...nel.org>, rashmica.g@...il.com,
Michael Neuling <mikey@...ling.org>,
Balbir Singh <bsingharora@...il.com>, nfont@...ux.vnet.ibm.com,
jallen@...ux.vnet.ibm.com,
Andrew Morton <akpm@...ux-foundation.org>,
Michal Hocko <mhocko@...e.com>,
Dan Williams <dan.j.williams@...el.com>,
Joonsoo Kim <iamjoonsoo.kim@....com>,
Vlastimil Babka <vbabka@...e.cz>,
Pavel Tatashin <pasha.tatashin@...cle.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
osalvador@...e.de, yasu.isimatu@...il.com, malat@...ian.org
Subject: Re: [PATCH v1 1/6] mm/memory_hotplug: make remove_memory() take the device_hotplug_lock
On Tue, Sep 18, 2018 at 1:48 PM David Hildenbrand <david@...hat.com> wrote:
>
> remove_memory() is exported right now but requires the
> device_hotplug_lock, which is not exported. So let's provide a variant
> that takes the lock and only export that one.
>
> The lock is already held in
> arch/powerpc/platforms/pseries/hotplug-memory.c
> drivers/acpi/acpi_memhotplug.c
> So, let's use the locked variant.
>
> The lock is not held (but taken in)
> arch/powerpc/platforms/powernv/memtrace.c
> So let's keep using the (now) locked variant.
>
> Apart from that, there are not other users in the tree.
>
> Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
> Cc: Paul Mackerras <paulus@...ba.org>
> Cc: Michael Ellerman <mpe@...erman.id.au>
> Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>
> Cc: Len Brown <lenb@...nel.org>
> Cc: Rashmica Gupta <rashmica.g@...il.com>
> Cc: Michael Neuling <mikey@...ling.org>
> Cc: Balbir Singh <bsingharora@...il.com>
> Cc: Nathan Fontenot <nfont@...ux.vnet.ibm.com>
> Cc: John Allen <jallen@...ux.vnet.ibm.com>
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Cc: Michal Hocko <mhocko@...e.com>
> Cc: Dan Williams <dan.j.williams@...el.com>
> Cc: Joonsoo Kim <iamjoonsoo.kim@....com>
> Cc: Vlastimil Babka <vbabka@...e.cz>
> Cc: Pavel Tatashin <pasha.tatashin@...cle.com>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Cc: Oscar Salvador <osalvador@...e.de>
> Cc: YASUAKI ISHIMATSU <yasu.isimatu@...il.com>
> Cc: Mathieu Malaterre <malat@...ian.org>
> Reviewed-by: Pavel Tatashin <pavel.tatashin@...rosoft.com>
> Signed-off-by: David Hildenbrand <david@...hat.com>
> ---
> arch/powerpc/platforms/powernv/memtrace.c | 2 --
> arch/powerpc/platforms/pseries/hotplug-memory.c | 6 +++---
> drivers/acpi/acpi_memhotplug.c | 2 +-
> include/linux/memory_hotplug.h | 3 ++-
> mm/memory_hotplug.c | 9 ++++++++-
> 5 files changed, 14 insertions(+), 8 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
> index 51dc398ae3f7..8f1cd4f3bfd5 100644
> --- a/arch/powerpc/platforms/powernv/memtrace.c
> +++ b/arch/powerpc/platforms/powernv/memtrace.c
> @@ -90,9 +90,7 @@ static bool memtrace_offline_pages(u32 nid, u64 start_pfn, u64 nr_pages)
> walk_memory_range(start_pfn, end_pfn, (void *)MEM_OFFLINE,
> change_memblock_state);
>
> - lock_device_hotplug();
> remove_memory(nid, start_pfn << PAGE_SHIFT, nr_pages << PAGE_SHIFT);
> - unlock_device_hotplug();
>
> return true;
> }
> diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
> index c1578f54c626..b3f54466e25f 100644
> --- a/arch/powerpc/platforms/pseries/hotplug-memory.c
> +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
> @@ -334,7 +334,7 @@ static int pseries_remove_memblock(unsigned long base, unsigned int memblock_siz
> nid = memory_add_physaddr_to_nid(base);
>
> for (i = 0; i < sections_per_block; i++) {
> - remove_memory(nid, base, MIN_MEMORY_BLOCK_SIZE);
> + __remove_memory(nid, base, MIN_MEMORY_BLOCK_SIZE);
> base += MIN_MEMORY_BLOCK_SIZE;
> }
>
> @@ -423,7 +423,7 @@ static int dlpar_remove_lmb(struct drmem_lmb *lmb)
> block_sz = pseries_memory_block_size();
> nid = memory_add_physaddr_to_nid(lmb->base_addr);
>
> - remove_memory(nid, lmb->base_addr, block_sz);
> + __remove_memory(nid, lmb->base_addr, block_sz);
>
> /* Update memory regions for memory remove */
> memblock_remove(lmb->base_addr, block_sz);
> @@ -710,7 +710,7 @@ static int dlpar_add_lmb(struct drmem_lmb *lmb)
>
> rc = dlpar_online_lmb(lmb);
> if (rc) {
> - remove_memory(nid, lmb->base_addr, block_sz);
> + __remove_memory(nid, lmb->base_addr, block_sz);
> dlpar_remove_device_tree_lmb(lmb);
> } else {
> lmb->flags |= DRCONF_MEM_ASSIGNED;
> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
> index 6b0d3ef7309c..811148415993 100644
> --- a/drivers/acpi/acpi_memhotplug.c
> +++ b/drivers/acpi/acpi_memhotplug.c
> @@ -282,7 +282,7 @@ static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
> nid = memory_add_physaddr_to_nid(info->start_addr);
>
> acpi_unbind_memory_blocks(info);
> - remove_memory(nid, info->start_addr, info->length);
> + __remove_memory(nid, info->start_addr, info->length);
> list_del(&info->list);
> kfree(info);
> }
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index 34a28227068d..1f096852f479 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -301,6 +301,7 @@ extern bool is_mem_section_removable(unsigned long pfn, unsigned long nr_pages);
> extern void try_offline_node(int nid);
> extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
> extern void remove_memory(int nid, u64 start, u64 size);
> +extern void __remove_memory(int nid, u64 start, u64 size);
>
> #else
> static inline bool is_mem_section_removable(unsigned long pfn,
> @@ -317,6 +318,7 @@ static inline int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
> }
>
> static inline void remove_memory(int nid, u64 start, u64 size) {}
> +static inline void __remove_memory(int nid, u64 start, u64 size) {}
> #endif /* CONFIG_MEMORY_HOTREMOVE */
>
> extern void __ref free_area_init_core_hotplug(int nid);
> @@ -330,7 +332,6 @@ extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
> unsigned long nr_pages, struct vmem_altmap *altmap);
> extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
> extern bool is_memblock_offlined(struct memory_block *mem);
> -extern void remove_memory(int nid, u64 start, u64 size);
> extern int sparse_add_one_section(struct pglist_data *pgdat,
> unsigned long start_pfn, struct vmem_altmap *altmap);
> extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 38d94b703e9d..b8b1bd970322 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1873,7 +1873,7 @@ EXPORT_SYMBOL(try_offline_node);
> * and online/offline operations before this call, as required by
> * try_offline_node().
> */
> -void __ref remove_memory(int nid, u64 start, u64 size)
> +void __ref __remove_memory(int nid, u64 start, u64 size)
> {
> int ret;
>
> @@ -1902,5 +1902,12 @@ void __ref remove_memory(int nid, u64 start, u64 size)
>
> mem_hotplug_done();
> }
> +
> +void remove_memory(int nid, u64 start, u64 size)
> +{
> + lock_device_hotplug();
> + __remove_memory(nid, start, size);
> + unlock_device_hotplug();
> +}
> EXPORT_SYMBOL_GPL(remove_memory);
> #endif /* CONFIG_MEMORY_HOTREMOVE */
> --
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
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