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shm: split up buffer struct into internal/private and public parts

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Daniel Eklöf 2021-07-15 22:17:12 +02:00
parent a18959f2df
commit 75f7f21a48
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GPG key ID: 5BBD4992C116573F
2 changed files with 127 additions and 99 deletions
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205
shm.c
View file

@ -55,11 +55,34 @@
*/ */
static off_t max_pool_size = 512 * 1024 * 1024; static off_t max_pool_size = 512 * 1024 * 1024;
static tll(struct buffer) buffers;
static bool can_punch_hole = false; static bool can_punch_hole = false;
static bool can_punch_hole_initialized = false; static bool can_punch_hole_initialized = false;
struct buffer_pool {
int fd; /* memfd */
struct wl_shm_pool *wl_pool;
void *real_mmapped; /* Address returned from mmap */
size_t mmap_size; /* Size of mmap (>= size) */
size_t ref_count;
};
struct buffer_private {
struct buffer public;
bool busy; /* Owned by compositor */
unsigned long cookie;
struct buffer_pool *pool;
off_t offset; /* Offset into memfd where data begins */
bool scrollable;
bool purge; /* True if this buffer should be destroyed */
};
static tll(struct buffer_private) buffers;
#undef MEASURE_SHM_ALLOCS #undef MEASURE_SHM_ALLOCS
#if defined(MEASURE_SHM_ALLOCS) #if defined(MEASURE_SHM_ALLOCS)
static size_t max_alloced = 0; static size_t max_alloced = 0;
@ -114,14 +137,14 @@ pool_unref(struct buffer_pool *pool)
} }
static void static void
buffer_destroy(struct buffer *buf) buffer_destroy(struct buffer_private *buf)
{ {
buffer_destroy_dont_close(buf); buffer_destroy_dont_close(&buf->public);
pool_unref(buf->pool); pool_unref(buf->pool);
buf->pool = NULL; buf->pool = NULL;
free(buf->scroll_damage); free(buf->public.scroll_damage);
pixman_region32_fini(&buf->dirty); pixman_region32_fini(&buf->public.dirty);
} }
void void
@ -140,12 +163,12 @@ shm_fini(void)
static void static void
buffer_release(void *data, struct wl_buffer *wl_buffer) buffer_release(void *data, struct wl_buffer *wl_buffer)
{ {
struct buffer *buffer = data; struct buffer_private *buffer = data;
LOG_DBG("release: cookie=%lx (buf=%p, total buffer count: %zu)", LOG_DBG("release: cookie=%lx (buf=%p, total buffer count: %zu)",
buffer->cookie, (void *)buffer, tll_length(buffers)); buffer->cookie, (void *)buffer, tll_length(buffers));
xassert(buffer->wl_buf == wl_buffer); xassert(buffer->public.wl_buf == wl_buffer);
xassert(buffer->busy); xassert(buffer->busy);
buffer->busy = false; buffer->busy = false;
} }
@ -174,23 +197,24 @@ page_size(void)
#endif #endif
static bool static bool
instantiate_offset(struct wl_shm *shm, struct buffer *buf, off_t new_offset) instantiate_offset(struct wl_shm *shm, struct buffer_private *buf, off_t new_offset)
{ {
xassert(buf->mmapped == NULL); xassert(buf->public.mmapped == NULL);
xassert(buf->wl_buf == NULL); xassert(buf->public.pix == NULL);
xassert(buf->pix == NULL); xassert(buf->public.wl_buf == NULL);
xassert(buf->pool != NULL); xassert(buf->pool != NULL);
const struct buffer_pool *pool = buf->pool; const struct buffer_pool *pool = buf->pool;
void *mmapped = MAP_FAILED; void *mmapped = MAP_FAILED;
struct wl_buffer *wl_buf = NULL; struct wl_buffer *wl_buf = NULL;
pixman_image_t **pix = xcalloc(buf->pix_instances, sizeof(*pix)); pixman_image_t **pix = xcalloc(buf->public.pix_instances, sizeof(*pix));
mmapped = (uint8_t *)pool->real_mmapped + new_offset; mmapped = (uint8_t *)pool->real_mmapped + new_offset;
wl_buf = wl_shm_pool_create_buffer( wl_buf = wl_shm_pool_create_buffer(
pool->wl_pool, new_offset, buf->width, buf->height, buf->stride, pool->wl_pool, new_offset,
buf->public.width, buf->public.height, buf->public.stride,
WL_SHM_FORMAT_ARGB8888); WL_SHM_FORMAT_ARGB8888);
if (wl_buf == NULL) { if (wl_buf == NULL) {
@ -199,26 +223,27 @@ instantiate_offset(struct wl_shm *shm, struct buffer *buf, off_t new_offset)
} }
/* One pixman image for each worker thread (do we really need multiple?) */ /* One pixman image for each worker thread (do we really need multiple?) */
for (size_t i = 0; i < buf->pix_instances; i++) { for (size_t i = 0; i < buf->public.pix_instances; i++) {
pix[i] = pixman_image_create_bits_no_clear( pix[i] = pixman_image_create_bits_no_clear(
PIXMAN_a8r8g8b8, buf->width, buf->height, (uint32_t *)mmapped, buf->stride); PIXMAN_a8r8g8b8, buf->public.width, buf->public.height,
(uint32_t *)mmapped, buf->public.stride);
if (pix[i] == NULL) { if (pix[i] == NULL) {
LOG_ERR("failed to create pixman image"); LOG_ERR("failed to create pixman image");
goto err; goto err;
} }
} }
buf->mmapped = mmapped; buf->public.mmapped = mmapped;
buf->public.wl_buf = wl_buf;
buf->public.pix = pix;
buf->offset = new_offset; buf->offset = new_offset;
buf->wl_buf = wl_buf;
buf->pix = pix;
wl_buffer_add_listener(wl_buf, &buffer_listener, buf); wl_buffer_add_listener(wl_buf, &buffer_listener, buf);
return true; return true;
err: err:
if (pix != NULL) { if (pix != NULL) {
for (size_t i = 0; i < buf->pix_instances; i++) for (size_t i = 0; i < buf->public.pix_instances; i++)
if (pix[i] != NULL) if (pix[i] != NULL)
pixman_image_unref(pix[i]); pixman_image_unref(pix[i]);
} }
@ -235,7 +260,7 @@ destroy_all_purgeables(void)
{ {
/* Purge buffers marked for purging */ /* Purge buffers marked for purging */
tll_foreach(buffers, it) { tll_foreach(buffers, it) {
if (it->item.locked) if (it->item.public.locked)
continue; continue;
if (!it->item.purge) if (!it->item.purge)
@ -393,29 +418,31 @@ get_new_buffers(struct wl_shm *shm, size_t count,
/* Push to list of available buffers, but marked as 'busy' */ /* Push to list of available buffers, but marked as 'busy' */
tll_push_front( tll_push_front(
buffers, buffers,
((struct buffer){ ((struct buffer_private){
.public = {
.width = info[i].width,
.height = info[i].height,
.stride = stride[i],
.size = sizes[i],
.pix_instances = pix_instances,
.age = 1234, /* Force a full repaint */
},
.cookie = info[i].cookie, .cookie = info[i].cookie,
.width = info[i].width,
.height = info[i].height,
.stride = stride[i],
.busy = true, .busy = true,
.purge = immediate_purge, .purge = immediate_purge,
.size = sizes[i],
.pix_instances = pix_instances,
.pool = pool, .pool = pool,
.scrollable = scrollable, .scrollable = scrollable,
.offset = 0, .offset = 0,
.age = 1234, /* Force a full repaint */
})); }));
struct buffer *buf = &tll_front(buffers); struct buffer_private *buf = &tll_front(buffers);
if (!instantiate_offset(shm, buf, offset)) if (!instantiate_offset(shm, buf, offset))
goto err; goto err;
pixman_region32_init(&buf->dirty); pixman_region32_init(&buf->public.dirty);
pool->ref_count++; pool->ref_count++;
offset += buf->size; offset += buf->public.size;
bufs[i] = buf; bufs[i] = &buf->public;
} }
#if defined(MEASURE_SHM_ALLOCS) && MEASURE_SHM_ALLOCS #if defined(MEASURE_SHM_ALLOCS) && MEASURE_SHM_ALLOCS
@ -466,17 +493,17 @@ shm_get_buffer(struct wl_shm *shm, int width, int height, unsigned long cookie,
{ {
destroy_all_purgeables(); destroy_all_purgeables();
struct buffer *cached = NULL; struct buffer_private *cached = NULL;
tll_foreach(buffers, it) { tll_foreach(buffers, it) {
if (it->item.width != width) if (it->item.public.width != width)
continue; continue;
if (it->item.height != height) if (it->item.public.height != height)
continue; continue;
if (it->item.cookie != cookie) if (it->item.cookie != cookie)
continue; continue;
if (it->item.busy) if (it->item.busy)
it->item.age++; it->item.public.age++;
else else
#if FORCED_DOUBLE_BUFFERING #if FORCED_DOUBLE_BUFFERING
if (it->item.age == 0) if (it->item.age == 0)
@ -489,16 +516,16 @@ shm_get_buffer(struct wl_shm *shm, int width, int height, unsigned long cookie,
cookie, (void *)&it->item); cookie, (void *)&it->item);
it->item.busy = true; it->item.busy = true;
it->item.purge = false; it->item.purge = false;
pixman_region32_clear(&it->item.dirty); pixman_region32_clear(&it->item.public.dirty);
free(it->item.scroll_damage); free(it->item.public.scroll_damage);
it->item.scroll_damage = NULL; it->item.public.scroll_damage = NULL;
xassert(it->item.pix_instances == pix_instances); xassert(it->item.public.pix_instances == pix_instances);
cached = &it->item; cached = &it->item;
} else { } else {
/* We have multiple buffers eligible for /* We have multiple buffers eligible for
* re-use. Pick the “youngest” one, and mark the * re-use. Pick the “youngest” one, and mark the
* other one for purging */ * other one for purging */
if (it->item.age < cached->age) { if (it->item.public.age < cached->public.age) {
cached->purge = true; cached->purge = true;
cached = &it->item; cached = &it->item;
} else } else
@ -508,7 +535,7 @@ shm_get_buffer(struct wl_shm *shm, int width, int height, unsigned long cookie,
} }
if (cached != NULL) if (cached != NULL)
return cached; return &cached->public;
/* Mark old buffers associated with this cookie for purging */ /* Mark old buffers associated with this cookie for purging */
tll_foreach(buffers, it) { tll_foreach(buffers, it) {
@ -518,7 +545,7 @@ shm_get_buffer(struct wl_shm *shm, int width, int height, unsigned long cookie,
if (it->item.busy) if (it->item.busy)
continue; continue;
if (it->item.width == width && it->item.height == height) if (it->item.public.width == width && it->item.public.height == height)
continue; continue;
LOG_DBG("cookie=%lx: marking buffer %p for purging", cookie, (void *)&it->item); LOG_DBG("cookie=%lx: marking buffer %p for purging", cookie, (void *)&it->item);
@ -532,9 +559,10 @@ shm_get_buffer(struct wl_shm *shm, int width, int height, unsigned long cookie,
} }
bool bool
shm_can_scroll(const struct buffer *buf) shm_can_scroll(const struct buffer *_buf)
{ {
#if __SIZEOF_POINTER__ == 8 #if __SIZEOF_POINTER__ == 8
const struct buffer_private *buf = (const struct buffer_private *)_buf;
return can_punch_hole && max_pool_size > 0 && buf->scrollable; return can_punch_hole && max_pool_size > 0 && buf->scrollable;
#else #else
/* Not enough virtual address space in 32-bit */ /* Not enough virtual address space in 32-bit */
@ -544,17 +572,20 @@ shm_can_scroll(const struct buffer *buf)
#if __SIZEOF_POINTER__ == 8 && defined(FALLOC_FL_PUNCH_HOLE) #if __SIZEOF_POINTER__ == 8 && defined(FALLOC_FL_PUNCH_HOLE)
static bool static bool
wrap_buffer(struct wl_shm *shm, struct buffer *buf, off_t new_offset) wrap_buffer(struct wl_shm *shm, struct buffer_private *buf, off_t new_offset)
{ {
struct buffer_pool *pool = buf->pool; struct buffer_pool *pool = buf->pool;
xassert(pool->ref_count == 1); xassert(pool->ref_count == 1);
/* We don't allow overlapping offsets */ /* We don't allow overlapping offsets */
off_t UNUSED diff = off_t UNUSED diff = new_offset < buf->offset
new_offset < buf->offset ? buf->offset - new_offset : new_offset - buf->offset; ? buf->offset - new_offset
xassert(diff > buf->size); : new_offset - buf->offset;
xassert(diff > buf->public.size);
memcpy((uint8_t *)pool->real_mmapped + new_offset, buf->mmapped, buf->size); memcpy((uint8_t *)pool->real_mmapped + new_offset,
buf->public.mmapped,
buf->public.size);
off_t trim_ofs, trim_len; off_t trim_ofs, trim_len;
if (new_offset > buf->offset) { if (new_offset > buf->offset) {
@ -563,7 +594,7 @@ wrap_buffer(struct wl_shm *shm, struct buffer *buf, off_t new_offset)
trim_len = new_offset; trim_len = new_offset;
} else { } else {
/* Trim everything *after* the new buffer location */ /* Trim everything *after* the new buffer location */
trim_ofs = new_offset + buf->size; trim_ofs = new_offset + buf->public.size;
trim_len = pool->mmap_size - trim_ofs; trim_len = pool->mmap_size - trim_ofs;
} }
@ -577,12 +608,12 @@ wrap_buffer(struct wl_shm *shm, struct buffer *buf, off_t new_offset)
} }
/* Re-instantiate pixman+wl_buffer+raw pointersw */ /* Re-instantiate pixman+wl_buffer+raw pointersw */
buffer_destroy_dont_close(buf); buffer_destroy_dont_close(&buf->public);
return instantiate_offset(shm, buf, new_offset); return instantiate_offset(shm, buf, new_offset);
} }
static bool static bool
shm_scroll_forward(struct wl_shm *shm, struct buffer *buf, int rows, shm_scroll_forward(struct wl_shm *shm, struct buffer_private *buf, int rows,
int top_margin, int top_keep_rows, int top_margin, int top_keep_rows,
int bottom_margin, int bottom_keep_rows) int bottom_margin, int bottom_keep_rows)
{ {
@ -590,19 +621,19 @@ shm_scroll_forward(struct wl_shm *shm, struct buffer *buf, int rows,
xassert(can_punch_hole); xassert(can_punch_hole);
xassert(buf->busy); xassert(buf->busy);
xassert(buf->pix); xassert(buf->public.pix != NULL);
xassert(buf->wl_buf); xassert(buf->public.wl_buf != NULL);
xassert(pool != NULL); xassert(pool != NULL);
xassert(pool->ref_count == 1); xassert(pool->ref_count == 1);
xassert(pool->fd >= 0); xassert(pool->fd >= 0);
LOG_DBG("scrolling %d rows (%d bytes)", rows, rows * buf->stride); LOG_DBG("scrolling %d rows (%d bytes)", rows, rows * buf->stride);
const off_t diff = rows * buf->stride; const off_t diff = rows * buf->public.stride;
xassert(rows > 0); xassert(rows > 0);
xassert(diff < buf->size); xassert(diff < buf->public.size);
if (buf->offset + diff + buf->size > max_pool_size) { if (buf->offset + diff + buf->public.size > max_pool_size) {
LOG_DBG("memfd offset wrap around"); LOG_DBG("memfd offset wrap around");
if (!wrap_buffer(shm, buf, 0)) if (!wrap_buffer(shm, buf, 0))
goto err; goto err;
@ -610,7 +641,7 @@ shm_scroll_forward(struct wl_shm *shm, struct buffer *buf, int rows,
off_t new_offset = buf->offset + diff; off_t new_offset = buf->offset + diff;
xassert(new_offset > buf->offset); xassert(new_offset > buf->offset);
xassert(new_offset + buf->size <= max_pool_size); xassert(new_offset + buf->public.size <= max_pool_size);
#if TIME_SCROLL #if TIME_SCROLL
struct timeval time1; struct timeval time1;
@ -621,10 +652,13 @@ shm_scroll_forward(struct wl_shm *shm, struct buffer *buf, int rows,
if (top_keep_rows > 0) { if (top_keep_rows > 0) {
/* Copy current 'top' region to its new location */ /* Copy current 'top' region to its new location */
const int stride = buf->public.stride;
uint8_t *base = buf->public.mmapped;
memmove( memmove(
(uint8_t *)buf->mmapped + (top_margin + rows) * buf->stride, base + (top_margin + rows) * stride,
(uint8_t *)buf->mmapped + (top_margin + 0) * buf->stride, base + (top_margin + 0) * stride,
top_keep_rows * buf->stride); top_keep_rows * stride);
#if TIME_SCROLL #if TIME_SCROLL
gettimeofday(&time2, NULL); gettimeofday(&time2, NULL);
@ -634,7 +668,7 @@ shm_scroll_forward(struct wl_shm *shm, struct buffer *buf, int rows,
} }
/* Destroy old objects (they point to the old offset) */ /* Destroy old objects (they point to the old offset) */
buffer_destroy_dont_close(buf); buffer_destroy_dont_close(&buf->public);
/* Free unused memory - everything up until the new offset */ /* Free unused memory - everything up until the new offset */
const off_t trim_ofs = 0; const off_t trim_ofs = 0;
@ -668,10 +702,14 @@ shm_scroll_forward(struct wl_shm *shm, struct buffer *buf, int rows,
if (ret && bottom_keep_rows > 0) { if (ret && bottom_keep_rows > 0) {
/* Copy 'bottom' region to its new location */ /* Copy 'bottom' region to its new location */
const size_t size = buf->public.size;
const int stride = buf->public.stride;
uint8_t *base = buf->public.mmapped;
memmove( memmove(
(uint8_t *)buf->mmapped + buf->size - (bottom_margin + bottom_keep_rows) * buf->stride, base + size - (bottom_margin + bottom_keep_rows) * stride,
(uint8_t *)buf->mmapped + buf->size - (bottom_margin + rows + bottom_keep_rows) * buf->stride, base + size - (bottom_margin + rows + bottom_keep_rows) * stride,
bottom_keep_rows * buf->stride); bottom_keep_rows * stride);
#if TIME_SCROLL #if TIME_SCROLL
struct timeval time5; struct timeval time5;
@ -690,7 +728,7 @@ err:
} }
static bool static bool
shm_scroll_reverse(struct wl_shm *shm, struct buffer *buf, int rows, shm_scroll_reverse(struct wl_shm *shm, struct buffer_private *buf, int rows,
int top_margin, int top_keep_rows, int top_margin, int top_keep_rows,
int bottom_margin, int bottom_keep_rows) int bottom_margin, int bottom_keep_rows)
{ {
@ -699,10 +737,10 @@ shm_scroll_reverse(struct wl_shm *shm, struct buffer *buf, int rows,
struct buffer_pool *pool = buf->pool; struct buffer_pool *pool = buf->pool;
xassert(pool->ref_count == 1); xassert(pool->ref_count == 1);
const off_t diff = rows * buf->stride; const off_t diff = rows * buf->public.stride;
if (diff > buf->offset) { if (diff > buf->offset) {
LOG_DBG("memfd offset reverse wrap-around"); LOG_DBG("memfd offset reverse wrap-around");
if (!wrap_buffer(shm, buf, (max_pool_size - buf->size) & ~(page_size() - 1))) if (!wrap_buffer(shm, buf, (max_pool_size - buf->public.size) & ~(page_size() - 1)))
goto err; goto err;
} }
@ -720,10 +758,14 @@ shm_scroll_reverse(struct wl_shm *shm, struct buffer *buf, int rows,
if (bottom_keep_rows > 0) { if (bottom_keep_rows > 0) {
/* Copy 'bottom' region to its new location */ /* Copy 'bottom' region to its new location */
const size_t size = buf->public.size;
const int stride = buf->public.stride;
uint8_t *base = buf->public.mmapped;
memmove( memmove(
(uint8_t *)buf->mmapped + buf->size - (bottom_margin + rows + bottom_keep_rows) * buf->stride, base + size - (bottom_margin + rows + bottom_keep_rows) * stride,
(uint8_t *)buf->mmapped + buf->size - (bottom_margin + bottom_keep_rows) * buf->stride, base + size - (bottom_margin + bottom_keep_rows) * stride,
bottom_keep_rows * buf->stride); bottom_keep_rows * stride);
#if TIME_SCROLL #if TIME_SCROLL
gettimeofday(&time1, NULL); gettimeofday(&time1, NULL);
@ -733,10 +775,10 @@ shm_scroll_reverse(struct wl_shm *shm, struct buffer *buf, int rows,
} }
/* Destroy old objects (they point to the old offset) */ /* Destroy old objects (they point to the old offset) */
buffer_destroy_dont_close(buf); buffer_destroy_dont_close(&buf->public);
/* Free unused memory - everything after the relocated buffer */ /* Free unused memory - everything after the relocated buffer */
const off_t trim_ofs = new_offset + buf->size; const off_t trim_ofs = new_offset + buf->public.size;
const off_t trim_len = pool->mmap_size - trim_ofs; const off_t trim_len = pool->mmap_size - trim_ofs;
if (fallocate( if (fallocate(
@ -766,10 +808,13 @@ shm_scroll_reverse(struct wl_shm *shm, struct buffer *buf, int rows,
if (ret && top_keep_rows > 0) { if (ret && top_keep_rows > 0) {
/* Copy current 'top' region to its new location */ /* Copy current 'top' region to its new location */
const int stride = buf->public.stride;
uint8_t *base = buf->public.mmapped;
memmove( memmove(
(uint8_t *)buf->mmapped + (top_margin + 0) * buf->stride, base + (top_margin + 0) * stride,
(uint8_t *)buf->mmapped + (top_margin + rows) * buf->stride, base + (top_margin + rows) * stride,
top_keep_rows * buf->stride); top_keep_rows * stride);
#if TIME_SCROLL #if TIME_SCROLL
struct timeval time4; struct timeval time4;
@ -788,14 +833,16 @@ err:
#endif /* FALLOC_FL_PUNCH_HOLE */ #endif /* FALLOC_FL_PUNCH_HOLE */
bool bool
shm_scroll(struct wl_shm *shm, struct buffer *buf, int rows, shm_scroll(struct wl_shm *shm, struct buffer *_buf, int rows,
int top_margin, int top_keep_rows, int top_margin, int top_keep_rows,
int bottom_margin, int bottom_keep_rows) int bottom_margin, int bottom_keep_rows)
{ {
#if __SIZEOF_POINTER__ == 8 && defined(FALLOC_FL_PUNCH_HOLE) #if __SIZEOF_POINTER__ == 8 && defined(FALLOC_FL_PUNCH_HOLE)
if (!shm_can_scroll(buf)) if (!shm_can_scroll(_buf))
return false; return false;
struct buffer_private *buf = (struct buffer_private *)_buf;
xassert(rows != 0); xassert(rows != 0);
return rows > 0 return rows > 0
? shm_scroll_forward(shm, buf, rows, top_margin, top_keep_rows, bottom_margin, bottom_keep_rows) ? shm_scroll_forward(shm, buf, rows, top_margin, top_keep_rows, bottom_margin, bottom_keep_rows)
@ -817,7 +864,7 @@ shm_purge(struct wl_shm *shm, unsigned long cookie)
if (it->item.busy) { if (it->item.busy) {
LOG_WARN("deferring purge of 'busy' buffer (width=%d, height=%d)", LOG_WARN("deferring purge of 'busy' buffer (width=%d, height=%d)",
it->item.width, it->item.height); it->item.public.width, it->item.public.height);
it->item.purge = true; it->item.purge = true;
} else { } else {
buffer_destroy(&it->item); buffer_destroy(&it->item);

21
shm.h
View file

@ -9,25 +9,13 @@
#include "terminal.h" #include "terminal.h"
struct buffer_pool {
int fd; /* memfd */
struct wl_shm_pool *wl_pool;
void *real_mmapped; /* Address returned from mmap */
size_t mmap_size; /* Size of mmap (>= size) */
size_t ref_count;
};
struct buffer { struct buffer {
unsigned long cookie; bool locked; /* Caller owned, shm won’t destroy it */
int width; int width;
int height; int height;
int stride; int stride;
bool locked; /* Caller owned, shm won’t destroy it */
bool busy; /* Owned by compositor */
size_t size; /* Buffer size */ size_t size; /* Buffer size */
void *mmapped; /* Raw data (TODO: rename) */ void *mmapped; /* Raw data (TODO: rename) */
@ -35,13 +23,6 @@ struct buffer {
pixman_image_t **pix; pixman_image_t **pix;
size_t pix_instances; size_t pix_instances;
/* Internal */
struct buffer_pool *pool;
off_t offset; /* Offset into memfd where data begins */
bool scrollable;
bool purge; /* True if this buffer should be destroyed */
unsigned age; unsigned age;
struct damage *scroll_damage; struct damage *scroll_damage;
size_t scroll_damage_count; size_t scroll_damage_count;