From: Minchan Kim <minchan@xxxxxxxxxx> Subject: zsmalloc: introduce obj_allocated The usage pattern for obj_to_head is to check whether the zpage is allocated or not. Thus, introduce obj_allocated. Link: https://lkml.kernel.org/r/20211115185909.3949505-5-minchan@xxxxxxxxxx Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> Acked-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Tested-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Cc: Mike Galbraith <umgwanakikbuti@xxxxxxxxx> Cc: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/zsmalloc.c | 33 ++++++++++++++++----------------- 1 file changed, 16 insertions(+), 17 deletions(-) --- a/mm/zsmalloc.c~zsmalloc-introduce-obj_allocated +++ a/mm/zsmalloc.c @@ -877,13 +877,21 @@ static unsigned long handle_to_obj(unsig return *(unsigned long *)handle; } -static unsigned long obj_to_head(struct page *page, void *obj) +static bool obj_allocated(struct page *page, void *obj, unsigned long *phandle) { + unsigned long handle; + if (unlikely(PageHugeObject(page))) { VM_BUG_ON_PAGE(!is_first_page(page), page); - return page->index; + handle = page->index; } else - return *(unsigned long *)obj; + handle = *(unsigned long *)obj; + + if (!(handle & OBJ_ALLOCATED_TAG)) + return false; + + *phandle = handle & ~OBJ_ALLOCATED_TAG; + return true; } static inline int testpin_tag(unsigned long handle) @@ -1606,7 +1614,6 @@ static void zs_object_copy(struct size_c static unsigned long find_alloced_obj(struct size_class *class, struct page *page, int *obj_idx) { - unsigned long head; int offset = 0; int index = *obj_idx; unsigned long handle = 0; @@ -1616,9 +1623,7 @@ static unsigned long find_alloced_obj(st offset += class->size * index; while (offset < PAGE_SIZE) { - head = obj_to_head(page, addr + offset); - if (head & OBJ_ALLOCATED_TAG) { - handle = head & ~OBJ_ALLOCATED_TAG; + if (obj_allocated(page, addr + offset, &handle)) { if (trypin_tag(handle)) break; handle = 0; @@ -1928,7 +1933,7 @@ static int zs_page_migrate(struct addres struct page *dummy; void *s_addr, *d_addr, *addr; int offset, pos; - unsigned long handle, head; + unsigned long handle; unsigned long old_obj, new_obj; unsigned int obj_idx; int ret = -EAGAIN; @@ -1964,9 +1969,7 @@ static int zs_page_migrate(struct addres pos = offset; s_addr = kmap_atomic(page); while (pos < PAGE_SIZE) { - head = obj_to_head(page, s_addr + pos); - if (head & OBJ_ALLOCATED_TAG) { - handle = head & ~OBJ_ALLOCATED_TAG; + if (obj_allocated(page, s_addr + pos, &handle)) { if (!trypin_tag(handle)) goto unpin_objects; } @@ -1982,9 +1985,7 @@ static int zs_page_migrate(struct addres for (addr = s_addr + offset; addr < s_addr + pos; addr += class->size) { - head = obj_to_head(page, addr); - if (head & OBJ_ALLOCATED_TAG) { - handle = head & ~OBJ_ALLOCATED_TAG; + if (obj_allocated(page, addr, &handle)) { BUG_ON(!testpin_tag(handle)); old_obj = handle_to_obj(handle); @@ -2029,9 +2030,7 @@ static int zs_page_migrate(struct addres unpin_objects: for (addr = s_addr + offset; addr < s_addr + pos; addr += class->size) { - head = obj_to_head(page, addr); - if (head & OBJ_ALLOCATED_TAG) { - handle = head & ~OBJ_ALLOCATED_TAG; + if (obj_allocated(page, addr, &handle)) { BUG_ON(!testpin_tag(handle)); unpin_tag(handle); } _
