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>
---
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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