[+cc Toshi]
On Fri, Jun 22, 2018 at 08:01:38PM +0800, guomin chen wrote:
> We've got a bug report indicating the hot-remove node resource
> release failed,when the memory on this node is divided into
> several sections.because the release_mem_region_adjustable()
> can only release one resource that must be [start,end].
Can you please include a URL for the bug report? That's useful for
additional details and gives hints about how future changes in this
area might be tested.
release_mem_region_adjustable() and the only call to it were added
by Toshi (cc'd):
825f787bb496 ("resource: add release_mem_region_adjustable()")
fe74ebb106a5 ("mm: change __remove_pages() to call release_mem_region_adjustable()")
> In my case, the BIOS supports faulty memory isolation. if BIOS
> detected bad memory block, the BIOS will isolates this badblock.
> And set this badblock memory to EfiUnusableMemory in EFI memory map
> base on UEFI 2.7 spec.For example in my system, the memory range on
> node2 is [mem 0x0000080000000000-0x00000807ffffffff].but the BIOS
> detected the [8004e000000-8004e0fffff] is a badblock memory.
> So the memory on node2 seem like this:
> 80000000000-8004dffffff : System RAM
> 8004e000000-8004e0fffff : Unusable memory
> 8004e100000-807ffffffff : System RAM
>
> Now, when offline the cpu node2,the kernel will try to release
> ioresource [mem 0x0000080000000000-0x00000807ffffffff]. at this
> time, the kernel will release failed,and output error message:
> "Unable to release resource <0x0000080000000000-0x00000807ffffffff>
> (-22)".
> Because the release_mem_region_adjustable() can only release one
> resource that must be [0x0000080000000000 , 0x00000807ffffffff].
> but now,the iomem resource on node2 [0x0000080000000000,
> 0x00000807ffffffff] are divided into three resources [80000000000-
> 8004dffffff],[8004e000000-8004e0fffff]and[8004e100000-807ffffffff].
>
> This patch help to Release multiple iomem resources at once when
> node hot-remove. Such as in above case, when hot-remove the cpu
> node2,the kernel will try to release resource [0x0000080000000000-
> 0x00000807ffffffff].And this patch will release three resources
> [80000000000-8004dffffff],[8004e000000-8004e0fffff] and
> [8004e100000-807ffffffff].
>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Brijesh Singh <brijesh.singh@xxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Cc: Yaowei Bai <baiyaowei@xxxxxxxxxxxxxxxxxxxx>
> Cc: Takashi Iwai <tiwai@xxxxxxx>
> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> Cc: linux-efi@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: Lee Chun-Yi <JLee@xxxxxxxx>
> Signed-off-by: guomin chen <guomin.chen@xxxxxxxx>
> ---
> kernel/resource.c | 73 ++++++++++++++++++++++++++++++++-----------------------
> 1 file changed, 43 insertions(+), 30 deletions(-)
>
> diff --git a/kernel/resource.c b/kernel/resource.c
> index 30e1bc68503b..959bcce4c405 100644
> --- a/kernel/resource.c
> +++ b/kernel/resource.c
> @@ -1240,6 +1240,7 @@ int release_mem_region_adjustable(struct resource *parent,
> struct resource *res;
> struct resource *new_res;
> resource_size_t end;
> + resource_size_t new_start = start;
> int ret = -EINVAL;
>
> end = start + size - 1;
> @@ -1257,7 +1258,7 @@ int release_mem_region_adjustable(struct resource *parent,
> break;
>
> /* look for the next resource if it does not fit into */
> - if (res->start > start || res->end < end) {
> + if (res->end < new_start) {
> p = &res->sibling;
> continue;
> }
> @@ -1271,42 +1272,54 @@ int release_mem_region_adjustable(struct resource *parent,
> }
>
> /* found the target resource; let's adjust accordingly */
> - if (res->start == start && res->end == end) {
> + if (res->start == new_start && res->end == end) {
> /* free the whole entry */
> *p = res->sibling;
> free_resource(res);
> ret = 0;
> - } else if (res->start == start && res->end != end) {
> - /* adjust the start */
> - ret = __adjust_resource(res, end + 1,
> - res->end - end);
> - } else if (res->start != start && res->end == end) {
> - /* adjust the end */
> - ret = __adjust_resource(res, res->start,
> - start - res->start);
> + } else if (res->end > end) {
> + if (res->start >= new_start) {
> + /* adjust the start */
> + ret = __adjust_resource(res, end + 1,
> + res->end - end);
> + } else {
> + /* split into two entries */
> + if (!new_res) {
> + ret = -ENOMEM;
> + break;
> + }
> + new_res->name = res->name;
> + new_res->start = end + 1;
> + new_res->end = res->end;
> + new_res->flags = res->flags;
> + new_res->desc = res->desc;
> + new_res->parent = res->parent;
> + new_res->sibling = res->sibling;
> + new_res->child = NULL;
> +
> + ret = __adjust_resource(res, res->start,
> + new_start - res->start);
> + if (ret)
> + break;
> + res->sibling = new_res;
> + new_res = NULL;
> + }
> } else {
> - /* split into two entries */
> - if (!new_res) {
> - ret = -ENOMEM;
> - break;
> + if (res->start < new_start) {
> + /* adjust the end */
> + ret = __adjust_resource(res, res->start,
> + new_start - res->start);
> + new_start = res->end+1;
> + p = &res->sibling;
> + } else {
> + new_start = res->end+1;
> + *p = res->sibling;
> + free_resource(res);
> + ret = 0;
> }
> - new_res->name = res->name;
> - new_res->start = end + 1;
> - new_res->end = res->end;
> - new_res->flags = res->flags;
> - new_res->desc = res->desc;
> - new_res->parent = res->parent;
> - new_res->sibling = res->sibling;
> - new_res->child = NULL;
> -
> - ret = __adjust_resource(res, res->start,
> - start - res->start);
> - if (ret)
> - break;
> - res->sibling = new_res;
> - new_res = NULL;
> + if (res->end < end)
> + continue;
> }
> -
> break;
> }
>
> --
> 2.12.3
>
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