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accel/tcg: Remove PageDesc code_bitmap 

This bitmap is created and discarded immediately.
We gain nothing by its existence.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220822232338.1727934-2-richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2022-08-22 16:23:22 -07:00
parent 8c6953cf03
commit 6981f7026a
1 changed files with 4 additions and 74 deletions
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78
accel/tcg/translate-all.c
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@ -102,21 +102,14 @@
#define assert_memory_lock() tcg_debug_assert(have_mmap_lock())
#endif
#define SMC_BITMAP_USE_THRESHOLD 10
typedef struct PageDesc {
/* list of TBs intersecting this ram page */
uintptr_t first_tb;
#ifdef CONFIG_SOFTMMU
/* in order to optimize self modifying code, we count the number
of lookups we do to a given page to use a bitmap */
unsigned long *code_bitmap;
unsigned int code_write_count;
#else
#ifdef CONFIG_USER_ONLY
unsigned long flags;
void *target_data;
#endif
#ifndef CONFIG_USER_ONLY
#ifdef CONFIG_SOFTMMU
QemuSpin lock;
#endif
} PageDesc;
@ -907,17 +900,6 @@ void tb_htable_init(void)
qht_init(&tb_ctx.htable, tb_cmp, CODE_GEN_HTABLE_SIZE, mode);
}
/* call with @p->lock held */
static inline void invalidate_page_bitmap(PageDesc *p)
{
assert_page_locked(p);
#ifdef CONFIG_SOFTMMU
g_free(p->code_bitmap);
p->code_bitmap = NULL;
p->code_write_count = 0;
#endif
}
/* Set to NULL all the 'first_tb' fields in all PageDescs. */
static void page_flush_tb_1(int level, void **lp)
{
@ -932,7 +914,6 @@ static void page_flush_tb_1(int level, void **lp)
for (i = 0; i < V_L2_SIZE; ++i) {
page_lock(&pd[i]);
pd[i].first_tb = (uintptr_t)NULL;
invalidate_page_bitmap(pd + i);
page_unlock(&pd[i]);
}
} else {
@ -1197,11 +1178,9 @@ static void do_tb_phys_invalidate(TranslationBlock *tb, bool rm_from_page_list)
if (rm_from_page_list) {
p = page_find(tb->page_addr[0] >> TARGET_PAGE_BITS);
tb_page_remove(p, tb);
invalidate_page_bitmap(p);
if (tb->page_addr[1] != -1) {
p = page_find(tb->page_addr[1] >> TARGET_PAGE_BITS);
tb_page_remove(p, tb);
invalidate_page_bitmap(p);
}
}
@ -1246,35 +1225,6 @@ void tb_phys_invalidate(TranslationBlock *tb, tb_page_addr_t page_addr)
}
}
#ifdef CONFIG_SOFTMMU
/* call with @p->lock held */
static void build_page_bitmap(PageDesc *p)
{
int n, tb_start, tb_end;
TranslationBlock *tb;
assert_page_locked(p);
p->code_bitmap = bitmap_new(TARGET_PAGE_SIZE);
PAGE_FOR_EACH_TB(p, tb, n) {
/* NOTE: this is subtle as a TB may span two physical pages */
if (n == 0) {
/* NOTE: tb_end may be after the end of the page, but
it is not a problem */
tb_start = tb->pc & ~TARGET_PAGE_MASK;
tb_end = tb_start + tb->size;
if (tb_end > TARGET_PAGE_SIZE) {
tb_end = TARGET_PAGE_SIZE;
}
} else {
tb_start = 0;
tb_end = ((tb->pc + tb->size) & ~TARGET_PAGE_MASK);
}
bitmap_set(p->code_bitmap, tb_start, tb_end - tb_start);
}
}
#endif
/* add the tb in the target page and protect it if necessary
*
* Called with mmap_lock held for user-mode emulation.
@ -1295,7 +1245,6 @@ static inline void tb_page_add(PageDesc *p, TranslationBlock *tb,
page_already_protected = p->first_tb != (uintptr_t)NULL;
#endif
p->first_tb = (uintptr_t)tb | n;
invalidate_page_bitmap(p);
#if defined(CONFIG_USER_ONLY)
/* translator_loop() must have made all TB pages non-writable */
@ -1357,10 +1306,8 @@ tb_link_page(TranslationBlock *tb, tb_page_addr_t phys_pc,
/* remove TB from the page(s) if we couldn't insert it */
if (unlikely(existing_tb)) {
tb_page_remove(p, tb);
invalidate_page_bitmap(p);
if (p2) {
tb_page_remove(p2, tb);
invalidate_page_bitmap(p2);
}
tb = existing_tb;
}
@ -1731,7 +1678,6 @@ tb_invalidate_phys_page_range__locked(struct page_collection *pages,
#if !defined(CONFIG_USER_ONLY)
/* if no code remaining, no need to continue to use slow writes */
if (!p->first_tb) {
invalidate_page_bitmap(p);
tlb_unprotect_code(start);
}
#endif
@ -1827,24 +1773,8 @@ void tb_invalidate_phys_page_fast(struct page_collection *pages,
}
assert_page_locked(p);
if (!p->code_bitmap &&
++p->code_write_count >= SMC_BITMAP_USE_THRESHOLD) {
build_page_bitmap(p);
}
if (p->code_bitmap) {
unsigned int nr;
unsigned long b;
nr = start & ~TARGET_PAGE_MASK;
b = p->code_bitmap[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG - 1));
if (b & ((1 << len) - 1)) {
goto do_invalidate;
}
} else {
do_invalidate:
tb_invalidate_phys_page_range__locked(pages, p, start, start + len,
retaddr);
}
tb_invalidate_phys_page_range__locked(pages, p, start, start + len,
retaddr);
}
#else
/* Called with mmap_lock held. If pc is not 0 then it indicates the