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/*
* Copyright © 2003 Anders Carlsson
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation, and that the name of Anders Carlsson not be used in
* advertising or publicity pertaining to distribution of the software without
* specific, written prior permission. Anders Carlsson makes no
* representations about the suitability of this software for any purpose. It
* is provided "as is" without express or implied warranty.
*
* ANDERS CARLSSON DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL ANDERS CARLSSON BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/** @file
* This allocator allocates blocks of memory by maintaining a list of areas
* and a score for each area. As an area is marked used, its score is
* incremented, and periodically all of the areas have their scores decayed by
* a fraction. When allocating, the contiguous block of areas with the minimum
* score is found and evicted in order to make room for the new allocation.
*/
#include "exa_priv.h"
#include <limits.h>
#include <assert.h>
#include <stdlib.h>
#if DEBUG_OFFSCREEN
#define DBG_OFFSCREEN(a) ErrorF a
#else
#define DBG_OFFSCREEN(a)
#endif
#if DEBUG_OFFSCREEN
static void
ExaOffscreenValidate (ScreenPtr pScreen)
{
ExaScreenPriv (pScreen);
ExaOffscreenArea *prev = 0, *area;
assert (pExaScr->info->offScreenAreas->base_offset ==
pExaScr->info->offScreenBase);
for (area = pExaScr->info->offScreenAreas; area; area = area->next)
{
assert (area->offset >= area->base_offset &&
area->offset < (area->base_offset + area->size));
if (prev)
assert (prev->base_offset + prev->area.size == area->base_offset);
prev = area;
}
assert (prev->base_offset + prev->size == pExaScr->info->memorySize);
}
#else
#define ExaOffscreenValidate(s)
#endif
static ExaOffscreenArea *
ExaOffscreenKickOut (ScreenPtr pScreen, ExaOffscreenArea *area)
{
if (area->save)
(*area->save) (pScreen, area);
return exaOffscreenFree (pScreen, area);
}
/**
* exaOffscreenAlloc allocates offscreen memory
*
* @param pScreen current screen
* @param size size in bytes of the allocation
* @param align byte alignment requirement for the offset of the allocated area
* @param locked whether the allocated area is locked and can't be kicked out
* @param save callback for when the area is evicted from memory
* @param privdata private data for the save callback.
*
* Allocates offscreen memory from the device associated with pScreen. size and
* align deteremine where and how large the allocated area is, and locked will
* mark whether it should be held in card memory. privdata may be any pointer
* for the save callback when the area is removed.
*
* Note that locked areas do get evicted on VT switch, because during that time
* all offscreen memory becomes inaccessible. This may change in the future,
* but drivers should be aware of this and provide a callback to mark that their
* locked allocation was evicted, and then restore it if necessary on EnterVT.
*/
ExaOffscreenArea *
exaOffscreenAlloc (ScreenPtr pScreen, int size, int align,
Bool locked,
ExaOffscreenSaveProc save,
pointer privData)
{
ExaOffscreenArea *area, *begin, *best;
ExaScreenPriv (pScreen);
int tmp, real_size = 0, best_score;
#if DEBUG_OFFSCREEN
static int number = 0;
ErrorF("================= ============ allocating a new pixmap %d\n", ++number);
#endif
ExaOffscreenValidate (pScreen);
if (!align)
align = 1;
if (!size)
{
DBG_OFFSCREEN (("Alloc 0x%x -> EMPTY\n", size));
return NULL;
}
/* throw out requests that cannot fit */
if (size > (pExaScr->info->memorySize - pExaScr->info->offScreenBase))
{
DBG_OFFSCREEN (("Alloc 0x%x vs (0x%lx) -> TOBIG\n", size,
pExaScr->info->memorySize -
pExaScr->info->offScreenBase));
return NULL;
}
/* Try to find a free space that'll fit. */
for (area = pExaScr->info->offScreenAreas; area; area = area->next)
{
/* skip allocated areas */
if (area->state != ExaOffscreenAvail)
continue;
/* adjust size to match alignment requirement */
real_size = size;
tmp = area->base_offset % align;
if (tmp)
real_size += (align - tmp);
/* does it fit? */
if (real_size <= area->size)
break;
}
if (!area)
{
/*
* Kick out existing users to make space.
*
* First, locate a region which can hold the desired object.
*/
/* prev points at the first object to boot */
best = NULL;
best_score = INT_MAX;
for (begin = pExaScr->info->offScreenAreas; begin != NULL;
begin = begin->next)
{
int avail, score;
ExaOffscreenArea *scan;
if (begin->state == ExaOffscreenLocked)
continue;
/* adjust size needed to account for alignment loss for this area */
real_size = size;
tmp = begin->base_offset % align;
if (tmp)
real_size += (align - tmp);
avail = 0;
score = 0;
/* now see if we can make room here, and how "costly" it'll be. */
for (scan = begin; scan != NULL; scan = scan->next)
{
if (scan->state == ExaOffscreenLocked) {
/* Can't make room here, start after this locked area. */
begin = scan;
break;
}
/* Score should only be non-zero for ExaOffscreenRemovable */
score += scan->score;
avail += scan->size;
if (avail >= real_size)
break;
}
/* Is it the best option we've found so far? */
if (avail >= real_size && score < best_score) {
best = begin;
best_score = score;
}
}
area = best;
if (!area)
{
DBG_OFFSCREEN (("Alloc 0x%x -> NOSPACE\n", size));
/* Could not allocate memory */
ExaOffscreenValidate (pScreen);
return NULL;
}
/* adjust size needed to account for alignment loss for this area */
real_size = size;
tmp = area->base_offset % align;
if (tmp)
real_size += (align - tmp);
/*
* Kick out first area if in use
*/
if (area->state != ExaOffscreenAvail)
area = ExaOffscreenKickOut (pScreen, area);
/*
* Now get the system to merge the other needed areas together
*/
while (area->size < real_size)
{
assert (area->next && area->next->state == ExaOffscreenRemovable);
(void) ExaOffscreenKickOut (pScreen, area->next);
}
}
/* save extra space in new area */
if (real_size < area->size)
{
ExaOffscreenArea *new_area = xalloc (sizeof (ExaOffscreenArea));
if (!new_area)
return NULL;
new_area->base_offset = area->base_offset + real_size;
new_area->offset = new_area->base_offset;
new_area->size = area->size - real_size;
new_area->state = ExaOffscreenAvail;
new_area->save = NULL;
new_area->score = 0;
new_area->next = area->next;
area->next = new_area;
area->size = real_size;
}
/*
* Mark this area as in use
*/
if (locked)
area->state = ExaOffscreenLocked;
else
area->state = ExaOffscreenRemovable;
area->privData = privData;
area->save = save;
area->score = 0;
area->offset = (area->base_offset + align - 1);
area->offset -= area->offset % align;
ExaOffscreenValidate (pScreen);
DBG_OFFSCREEN (("Alloc 0x%x -> 0x%x (0x%x)\n", size,
area->base_offset, area->offset));
return area;
}
void
ExaOffscreenSwapOut (ScreenPtr pScreen)
{
ExaScreenPriv (pScreen);
ExaOffscreenValidate (pScreen);
/* loop until a single free area spans the space */
for (;;)
{
ExaOffscreenArea *area = pExaScr->info->offScreenAreas;
if (!area)
break;
if (area->state == ExaOffscreenAvail)
{
area = area->next;
if (!area)
break;
}
assert (area->state != ExaOffscreenAvail);
(void) ExaOffscreenKickOut (pScreen, area);
ExaOffscreenValidate (pScreen);
}
ExaOffscreenValidate (pScreen);
ExaOffscreenFini (pScreen);
}
void
ExaOffscreenSwapIn (ScreenPtr pScreen)
{
exaOffscreenInit (pScreen);
}
void
exaEnableDisableFBAccess (int index, Bool enable)
{
ScreenPtr pScreen = screenInfo.screens[index];
ExaScreenPriv (pScreen);
if (!enable) {
ExaOffscreenSwapOut (pScreen);
pExaScr->swappedOut = TRUE;
} else {
ExaOffscreenSwapIn (pScreen);
pExaScr->swappedOut = FALSE;
}
}
/* merge the next free area into this one */
static void
ExaOffscreenMerge (ExaOffscreenArea *area)
{
ExaOffscreenArea *next = area->next;
/* account for space */
area->size += next->size;
/* frob pointer */
area->next = next->next;
xfree (next);
}
/**
* exaOffscreenFree frees an allocation.
*
* @param pScreen current screen
* @param area offscreen area to free
*
* exaOffscreenFree frees an allocation created by exaOffscreenAlloc. Note that
* the save callback of the area is not called, and it is up to the driver to
* do any cleanup necessary as a result.
*
* @return pointer to the newly freed area. This behavior should not be relied
* on.
*/
ExaOffscreenArea *
exaOffscreenFree (ScreenPtr pScreen, ExaOffscreenArea *area)
{
ExaScreenPriv(pScreen);
ExaOffscreenArea *next = area->next;
ExaOffscreenArea *prev;
DBG_OFFSCREEN (("Free 0x%x -> 0x%x (0x%x)\n", area->size,
area->base_offset, area->offset));
ExaOffscreenValidate (pScreen);
area->state = ExaOffscreenAvail;
area->save = NULL;
area->score = 0;
/*
* Find previous area
*/
if (area == pExaScr->info->offScreenAreas)
prev = NULL;
else
for (prev = pExaScr->info->offScreenAreas; prev; prev = prev->next)
if (prev->next == area)
break;
/* link with next area if free */
if (next && next->state == ExaOffscreenAvail)
ExaOffscreenMerge (area);
/* link with prev area if free */
if (prev && prev->state == ExaOffscreenAvail)
{
area = prev;
ExaOffscreenMerge (area);
}
ExaOffscreenValidate (pScreen);
DBG_OFFSCREEN(("\tdone freeing\n"));
return area;
}
void
ExaOffscreenMarkUsed (PixmapPtr pPixmap)
{
ExaPixmapPriv (pPixmap);
ExaScreenPriv (pPixmap->drawable.pScreen);
static int iter = 0;
if (!pExaPixmap->area)
return;
/* The numbers here are arbitrary. We may want to tune these. */
pExaPixmap->area->score += 100;
if (++iter == 10) {
ExaOffscreenArea *area;
for (area = pExaScr->info->offScreenAreas; area != NULL;
area = area->next)
{
if (area->state == ExaOffscreenRemovable)
area->score = (area->score * 7) / 8;
}
}
}
/**
* exaOffscreenInit initializes the offscreen memory manager.
*
* @param pScreen current screen
*
* exaOffscreenInit is called by exaDriverInit to set up the memory manager for
* the screen, if any offscreen memory is available.
*/
Bool
exaOffscreenInit (ScreenPtr pScreen)
{
ExaScreenPriv (pScreen);
ExaOffscreenArea *area;
/* Allocate a big free area */
area = xalloc (sizeof (ExaOffscreenArea));
if (!area)
return FALSE;
area->state = ExaOffscreenAvail;
area->base_offset = pExaScr->info->offScreenBase;
area->offset = area->base_offset;
area->size = pExaScr->info->memorySize - area->base_offset;
area->save = NULL;
area->next = NULL;
area->score = 0;
/* Add it to the free areas */
pExaScr->info->offScreenAreas = area;
ExaOffscreenValidate (pScreen);
return TRUE;
}
void
ExaOffscreenFini (ScreenPtr pScreen)
{
ExaScreenPriv (pScreen);
ExaOffscreenArea *area;
/* just free all of the area records */
while ((area = pExaScr->info->offScreenAreas))
{
pExaScr->info->offScreenAreas = area->next;
xfree (area);
}
}
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