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metadata: Make collision updates atomic #967

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Merged
robertbaldyga merged 1 commit into from
Jul 6, 2026
Merged

metadata: Make collision updates atomic #967

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49 changes: 40 additions & 9 deletions src/metadata/metadata_collision.c
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,37 @@
#include "metadata_internal.h"
#include "../utils/utils_cache_line.h"

static inline void ocf_metadata_list_info_set(
struct ocf_metadata_list_info *info,
ocf_cache_line_t next, ocf_cache_line_t prev)
{
struct ocf_metadata_list_info t = { };

t.next_col = next;
t.prev_col = prev;
info->entry = t.entry;
}

static inline void ocf_metadata_list_info_set_next(
struct ocf_metadata_list_info *info,
ocf_cache_line_t next)
{
struct ocf_metadata_list_info t = { .entry = info->entry };

t.next_col = next;
info->entry = t.entry;
}

static inline void ocf_metadata_list_info_set_prev(
struct ocf_metadata_list_info *info,
ocf_cache_line_t prev)
{
struct ocf_metadata_list_info t = { .entry = info->entry };

t.prev_col = prev;
info->entry = t.entry;
}

void ocf_metadata_set_collision_info(struct ocf_cache *cache,
ocf_cache_line_t line, ocf_cache_line_t next,
ocf_cache_line_t prev)
Expand All @@ -21,12 +52,10 @@ void ocf_metadata_set_collision_info(struct ocf_cache *cache,
info = ocf_metadata_raw_wr_access(cache,
&(ctrl->raw_desc[metadata_segment_list_info]), line);

if (info) {
info->next_col = next;
info->prev_col = prev;
} else {
if (info)
ocf_metadata_list_info_set(info, next, prev);
else
ocf_metadata_error(cache);
}
}

void ocf_metadata_set_collision_next(struct ocf_cache *cache,
Expand All @@ -40,7 +69,7 @@ void ocf_metadata_set_collision_next(struct ocf_cache *cache,
&(ctrl->raw_desc[metadata_segment_list_info]), line);

if (info)
info->next_col = next;
ocf_metadata_list_info_set_next(info, next);
else
ocf_metadata_error(cache);
}
Expand All @@ -56,7 +85,7 @@ void ocf_metadata_set_collision_prev(struct ocf_cache *cache,
&(ctrl->raw_desc[metadata_segment_list_info]), line);

if (info)
info->prev_col = prev;
ocf_metadata_list_info_set_prev(info, prev);
else
ocf_metadata_error(cache);
}
Expand All @@ -74,10 +103,12 @@ void ocf_metadata_get_collision_info(struct ocf_cache *cache,
info = ocf_metadata_raw_rd_access(cache,
&(ctrl->raw_desc[metadata_segment_list_info]), line);
if (info) {
/* Atomic read of the entry (aarch64/amd64) */
struct ocf_metadata_list_info t = { .entry = info->entry };
if (next)
*next = info->next_col;
*next = t.next_col;
if (prev)
*prev = info->prev_col;
*prev = t.prev_col;
} else {
ocf_metadata_error(cache);

Expand Down
19 changes: 12 additions & 7 deletions src/metadata/metadata_collision.h
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Original file line number Diff line number Diff line change
Expand Up @@ -15,13 +15,18 @@
*/

struct ocf_metadata_list_info {
/* Previous cache line in collision list */
ocf_cache_line_t prev_col : OCF_CACHE_LINE_BITS;
ocf_cache_line_t unused : 3;
/* Next cache line in collision list*/
ocf_cache_line_t next_col : OCF_CACHE_LINE_BITS;
ocf_cache_line_t unused2 : 3;
} __attribute__((packed));
union {
struct {
/* Previous cache line in collision list */
ocf_cache_line_t prev_col : OCF_CACHE_LINE_BITS;
ocf_cache_line_t unused : 3;
/* Next cache line in collision list*/
ocf_cache_line_t next_col : OCF_CACHE_LINE_BITS;
ocf_cache_line_t unused2 : 3;
} __attribute__((packed));
uint64_t entry;
};
};

/* Keep the struct ocf_metadata_list_info size of 8 bytes */
_Static_assert(sizeof(struct ocf_metadata_list_info) == sizeof(uint64_t),
Expand Down