mirror/nginx
1
0
Fork 0
mirror of https://github.com/nginx/nginx.git synced 2025-08-06 14:56:15 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

Slab: simplified allocation from slots.

Browse Source 
Removed code that would cause an endless loop, and removed condition
check that is always false.  The first page in the slot list is
guaranteed to satisfy an allocation.
This commit is contained in:
Ruslan Ermilov 2016-12-07 22:25:37 +03:00
parent 16de9fc3b5
commit 12abb66c41
1 changed files with 66 additions and 84 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

150
src/core/ngx_slab.c
View File

@ -215,84 +215,71 @@ ngx_slab_alloc_locked(ngx_slab_pool_t *pool, size_t size)
if (shift < ngx_slab_exact_shift) { if (shift < ngx_slab_exact_shift) {
do { bitmap = (uintptr_t *) ngx_slab_page_addr(pool, page);
bitmap = (uintptr_t *) ngx_slab_page_addr(pool, page);
map = (1 << (ngx_pagesize_shift - shift)) map = (1 << (ngx_pagesize_shift - shift))
/ (sizeof(uintptr_t) * 8); / (sizeof(uintptr_t) * 8);
for (n = 0; n < map; n++) { for (n = 0; n < map; n++) {
if (bitmap[n] != NGX_SLAB_BUSY) { if (bitmap[n] != NGX_SLAB_BUSY) {
for (m = 1, i = 0; m; m <<= 1, i++) {
if (bitmap[n] & m) {
continue;
}
bitmap[n] |= m;
i = ((n * sizeof(uintptr_t) * 8) << shift)
+ (i << shift);
if (bitmap[n] == NGX_SLAB_BUSY) {
for (n = n + 1; n < map; n++) {
if (bitmap[n] != NGX_SLAB_BUSY) {
p = (uintptr_t) bitmap + i;
goto done;
}
}
prev = ngx_slab_page_prev(page);
prev->next = page->next;
page->next->prev = page->prev;
page->next = NULL;
page->prev = NGX_SLAB_SMALL;
}
p = (uintptr_t) bitmap + i;
goto done;
}
}
}
page = page->next;
} while (page);
} else if (shift == ngx_slab_exact_shift) {
do {
if (page->slab != NGX_SLAB_BUSY) {
for (m = 1, i = 0; m; m <<= 1, i++) { for (m = 1, i = 0; m; m <<= 1, i++) {
if (page->slab & m) { if (bitmap[n] & m) {
continue; continue;
} }
page->slab |= m; bitmap[n] |= m;
i = ((n * sizeof(uintptr_t) * 8) << shift)
+ (i << shift);
if (bitmap[n] == NGX_SLAB_BUSY) {
for (n = n + 1; n < map; n++) {
if (bitmap[n] != NGX_SLAB_BUSY) {
p = (uintptr_t) bitmap + i;
goto done;
}
}
if (page->slab == NGX_SLAB_BUSY) {
prev = ngx_slab_page_prev(page); prev = ngx_slab_page_prev(page);
prev->next = page->next; prev->next = page->next;
page->next->prev = page->prev; page->next->prev = page->prev;
page->next = NULL; page->next = NULL;
page->prev = NGX_SLAB_EXACT; page->prev = NGX_SLAB_SMALL;
} }
p = ngx_slab_page_addr(pool, page) + (i << shift); p = (uintptr_t) bitmap + i;
goto done; goto done;
} }
} }
}
page = page->next; } else if (shift == ngx_slab_exact_shift) {
} while (page); for (m = 1, i = 0; m; m <<= 1, i++) {
if (page->slab & m) {
continue;
}
page->slab |= m;
if (page->slab == NGX_SLAB_BUSY) {
prev = ngx_slab_page_prev(page);
prev->next = page->next;
page->next->prev = page->prev;
page->next = NULL;
page->prev = NGX_SLAB_EXACT;
}
p = ngx_slab_page_addr(pool, page) + (i << shift);
goto done;
}
} else { /* shift > ngx_slab_exact_shift */ } else { /* shift > ngx_slab_exact_shift */
@ -301,38 +288,33 @@ ngx_slab_alloc_locked(ngx_slab_pool_t *pool, size_t size)
n = ((uintptr_t) 1 << n) - 1; n = ((uintptr_t) 1 << n) - 1;
mask = n << NGX_SLAB_MAP_SHIFT; mask = n << NGX_SLAB_MAP_SHIFT;
do { for (m = (uintptr_t) 1 << NGX_SLAB_MAP_SHIFT, i = 0;
if ((page->slab & NGX_SLAB_MAP_MASK) != mask) { m & mask;
m <<= 1, i++)
for (m = (uintptr_t) 1 << NGX_SLAB_MAP_SHIFT, i = 0; {
m & mask; if (page->slab & m) {
m <<= 1, i++) continue;
{
if (page->slab & m) {
continue;
}
page->slab |= m;
if ((page->slab & NGX_SLAB_MAP_MASK) == mask) {
prev = ngx_slab_page_prev(page);
prev->next = page->next;
page->next->prev = page->prev;
page->next = NULL;
page->prev = NGX_SLAB_BIG;
}
p = ngx_slab_page_addr(pool, page) + (i << shift);
goto done;
}
} }
page = page->next; page->slab |= m;
} while (page); if ((page->slab & NGX_SLAB_MAP_MASK) == mask) {
prev = ngx_slab_page_prev(page);
prev->next = page->next;
page->next->prev = page->prev;
page->next = NULL;
page->prev = NGX_SLAB_BIG;
}
p = ngx_slab_page_addr(pool, page) + (i << shift);
goto done;
}
} }
ngx_slab_error(pool, NGX_LOG_ALERT, "ngx_slab_alloc(): page is busy");
ngx_debug_point();
} }
page = ngx_slab_alloc_pages(pool, 1); page = ngx_slab_alloc_pages(pool, 1);