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kmalloc: bugfixes and performance improvements

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This commit is contained in:
anna 2021-09-30 00:32:07 +02:00
parent d4ee4e5953
commit 347bb5cc9c
Signed by: fef
GPG key ID: EC22E476DC2D3D84
2 changed files with 62 additions and 11 deletions
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23
kernel/mm/kmalloc.c
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@ -19,7 +19,7 @@
* doesn't have paging:
* <https://git.bsd.gay/fef/ardix/src/commit/c767d551d3301fc30f9fce30eda8f04e2f9a42ab/kernel/mm.c>
* As a matter of fact, this allocator is merely an extension of the one from
* Ardix with the only difference being that the heap can grow upwards.
* Ardix with the only difference being that the heap can be extended upwards.
*/
/**
@ -46,7 +46,7 @@ struct memblk {
/** @brief Used as the return value for `kmalloc()` */
u8 data[0];
/**
* @brief Used to get the copy of the low_size field at the end of
* @brief Used to get the copy of the size at the end of
* the block, right after the last byte of `data`
*/
usize high_size[0];
@ -274,7 +274,7 @@ static struct memblk *blk_try_merge(struct memblk *blk)
if (blk_get_size(cursor) >= blk_get_size(blk))
break;
}
clist_add_first(&cursor->clink, &blk->clink);
clist_add(&cursor->clink, &blk->clink);
return blk;
}
@ -292,13 +292,14 @@ static struct memblk *blk_merge(struct memblk *bottom, struct memblk *top)
static struct memblk *blk_slice(struct memblk *blk, usize slice_size)
{
struct memblk *cursor = clist_prev_entry(blk, clink);
clist_del(&blk->clink);
/*
* If the remaining low_size is less than the minimum allocation unit, we
* If the remaining size is less than the minimum allocation unit, we
* hand out the entire block. Additionally, we must add an underflow
* check which happens if the slice low_size is less than OVERHEAD smaller
* than the full block low_size.
* check which happens if the slice size is less than OVERHEAD smaller
* than the full block size.
*/
usize rest_size = blk_get_size(blk) - slice_size - OVERHEAD;
if (rest_size < MIN_SIZE || rest_size + OVERHEAD < rest_size) {
@ -316,8 +317,7 @@ static struct memblk *blk_slice(struct memblk *blk, usize slice_size)
blk_set_alloc(blk);
blk_clear_border_end(blk);
struct memblk *cursor;
clist_foreach_entry(&blocks, cursor, clink) {
clist_foreach_entry_rev_continue(&blocks, cursor, clink) {
if (blk_get_size(cursor) <= rest_size)
break;
}
@ -348,6 +348,11 @@ static inline struct memblk *blk_next(struct memblk *blk)
static inline usize blk_get_size(struct memblk *blk)
{
# ifdef DEBUG
usize index = blk->low_size[0] / sizeof(blk->low_size[0]);
if ((blk->low_size[0] & SIZE_MASK) != (blk->high_size[index] & SIZE_MASK))
kprintf("Memory corruption in block %p detected!\n", blk);
# endif
return blk->low_size[0] & SIZE_MASK;
}
@ -356,7 +361,7 @@ static void blk_set_size(struct memblk *blk, usize size)
/* don't affect flags */
blk->low_size[0] &= ~SIZE_MASK;
# ifdef DEBUG
if (size & SIZE_MASK)
if (size & ~SIZE_MASK)
kprintf("Unaligned size in blk_set_size()\n");
# endif
blk->low_size[0] |= size & SIZE_MASK;