On 07/18/2016 10:08 AM, Sahil Mehta wrote:
> Indexed-count remove for memory hotplug guarantees that a contiguous block
> of <count> lmbs beginning at a specified <index> will be unassigned (NOT
> that <count> lmbs will be removed). Because of Qemu's per-DIMM memory
> management, the removal of a contiguous block of memory currently
> requires a series of individual calls. Indexed-count remove reduces
> this series into a single call.
>
> Signed-off-by: Sahil Mehta <sme...@linux.vnet.ibm.com>
Reviewed-by: Nathan Fontenot <nf...@linux.vnet.ibm.com>
> ---
> v2: -use u32s drc_index and count instead of u32 ic[]
> in dlpar_memory
>
> arch/powerpc/platforms/pseries/hotplug-memory.c | 84
> +++++++++++++++++++++++
> 1 file changed, 84 insertions(+)
>
> diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c
> b/arch/powerpc/platforms/pseries/hotplug-memory.c
> index d7942ca..244e1a8 100644
> --- a/arch/powerpc/platforms/pseries/hotplug-memory.c
> +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
> @@ -503,6 +503,86 @@ static int dlpar_memory_remove_by_index(u32 drc_index,
> struct property *prop)
> return rc;
> }
>
> +static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index,
> + struct property *prop)
> +{
> + struct of_drconf_cell *lmbs;
> + u32 num_lmbs, *p;
> + int i, rc;
> + int lmbs_available = 0, start_index = 0, end_index;
> +
> + pr_info("Attempting to hot-remove %u LMB(s) at %x\n",
> + lmbs_to_remove, drc_index);
> +
> + if (lmbs_to_remove == 0)
> + return -EINVAL;
> +
> + p = prop->value;
> + num_lmbs = *p++;
> + lmbs = (struct of_drconf_cell *)p;
> +
> + /* Navigate to drc_index */
> + while (start_index < num_lmbs) {
> + if (lmbs[start_index].drc_index == drc_index)
> + break;
> +
> + start_index++;
> + }
> +
> + end_index = start_index + lmbs_to_remove;
> +
> + /* Validate that there are enough LMBs to satisfy the request */
> + for (i = start_index; i < end_index; i++) {
> + if (lmbs[i].flags & DRCONF_MEM_RESERVED)
> + break;
> +
> + lmbs_available++;
> + }
> +
> + if (lmbs_available < lmbs_to_remove)
> + return -EINVAL;
> +
> + for (i = 0; i < end_index; i++) {
> + if (!(lmbs[i].flags & DRCONF_MEM_ASSIGNED))
> + continue;
> +
> + rc = dlpar_remove_lmb(&lmbs[i]);
> + if (rc)
> + break;
> +
> + lmbs[i].reserved = 1;
> + }
> +
> + if (rc) {
> + pr_err("Memory indexed-count-remove failed, adding any removed
> LMBs\n");
> +
> + for (i = start_index; i < end_index; i++) {
> + if (!lmbs[i].reserved)
> + continue;
> +
> + rc = dlpar_add_lmb(&lmbs[i]);
> + if (rc)
> + pr_err("Failed to add LMB, drc index %x\n",
> + be32_to_cpu(lmbs[i].drc_index));
> +
> + lmbs[i].reserved = 0;
> + }
> + rc = -EINVAL;
> + } else {
> + for (i = start_index; i < end_index; i++) {
> + if (!lmbs[i].reserved)
> + continue;
> +
> + pr_info("Memory at %llx (drc index %x) was
> hot-removed\n",
> + lmbs[i].base_addr, lmbs[i].drc_index);
> +
> + lmbs[i].reserved = 0;
> + }
> + }
> +
> + return rc;
> +}
> +
> #else
> static inline int pseries_remove_memblock(unsigned long base,
> unsigned int memblock_size)
> @@ -821,6 +901,10 @@ int dlpar_memory(struct pseries_hp_errorlog *hp_elog)
> } else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX) {
> drc_index = hp_elog->_drc_u.drc_index;
> rc = dlpar_memory_remove_by_index(drc_index, prop);
> + } else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_IC) {
> + count = hp_elog->_drc_u.indexed_count[0];
> + drc_index = hp_elog->_drc_u.indexed_count[1];
> + rc = dlpar_memory_remove_by_ic(count, drc_index, prop);
> } else
> rc = -EINVAL;
> break;
>
> On 07/18/2016 10:04 AM, Sahil Mehta wrote:
>> Indexed-count memory management allows addition and removal of contiguous
>> lmb blocks with a single command. When compared to the series of calls
>> previously required to manage contiguous blocks, indexed-count decreases
>> command frequency and reduces risk of buffer overflow.
>>
>> Changes in v2:
>> --------------
>> -[PATCH 1/2]: -remove potential memory leak when parsing command
>> -use u32s drc_index and count instead of u32 ic[]
>> in dlpar_memory
>> -[PATCH 2/2]: -use u32s drc_index and count instead of u32 ic[]
>> in dlpar_memory
>>
>> -Sahil Mehta
>> ---
>> include/asm/rtas.h | 2
>> platforms/pseries/dlpar.c | 34 ++++++
>> platforms/pseries/hotplug-memory.c | 184
>> +++++++++++++++++++++++++++++++++++--
>> 3 files changed, 208 insertions(+), 12 deletions(-)
>>
>> _______________________________________________
>> Linuxppc-dev mailing list
>> Linuxppc-dev@lists.ozlabs.org
>> https://lists.ozlabs.org/listinfo/linuxppc-dev
>>
>
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