md/dm-vdo/memory-alloc.c

1 // SPDX-License-Identifier: GPL-2.0-only
13 #include "memory-alloc.h"
38  * @flag_ptr: Location of the allocation-allowed flag
71  * performance-critical stage for us, so a linked list should be fine.
113 	memory_stats.kmalloc_blocks--;  in remove_kmalloc_block()
114 	memory_stats.kmalloc_bytes -= size;  in remove_kmalloc_block()
123 	block->next = memory_stats.vmalloc_list;  in add_vmalloc_block()
126 	memory_stats.vmalloc_bytes += block->size;  in add_vmalloc_block()
140 	     block_ptr = &block->next) {  in remove_vmalloc_block()
141 		if (block->ptr == ptr) {  in remove_vmalloc_block()
142 			*block_ptr = block->next;  in remove_vmalloc_block()
143 			memory_stats.vmalloc_blocks--;  in remove_vmalloc_block()
144 			memory_stats.vmalloc_bytes -= block->size;  in remove_vmalloc_block()
171  * Linux memory page map can become so fragmented that kmalloc will not give us a 32KB chunk. We
172  * have used vmalloc as a backup to kmalloc in the past, and a follow-up vmalloc of 32KB will work.
175  * The kmalloc/vmalloc boundary is set at 4KB, and kmalloc gets the 4KB requests. There is no
176  * strong reason for favoring either kmalloc or vmalloc for 4KB requests, except that tracking
178  * boundary results in 132 vmalloc calls. Using vmalloc for requests of exactly 4KB results in an
205 	 * freeing memory such as compaction (which removes fragmentation) and page-out. There is  in vdo_allocate_memory()
210 	 * The caller must handle failure, but can reasonably do so by failing a higher-level  in vdo_allocate_memory()
220 		return -EINVAL;  in vdo_allocate_memory()
236 			 * no page available. A short sleep may allow the page reclaimer to  in vdo_allocate_memory()
237 			 * free a page.  in vdo_allocate_memory()
251 			 * are no pages available. A short sleep may allow the page reclaimer  in vdo_allocate_memory()
254 			 * For larger allocations, the page_alloc code is racing against the page  in vdo_allocate_memory()
255 			 * reclaimer. If the page reclaimer can stay ahead of page_alloc, the  in vdo_allocate_memory()
256 			 * __vmalloc will succeed. But if page_alloc overtakes the page reclaimer,  in vdo_allocate_memory()
264 				if (jiffies_to_msecs(jiffies - start_time) > 1000) {  in vdo_allocate_memory()
276 				block->ptr = p;  in vdo_allocate_memory()
277 				block->size = PAGE_ALIGN(size);  in vdo_allocate_memory()
288 			      size, what, jiffies_to_msecs(jiffies - start_time));  in vdo_allocate_memory()
289 		return -ENOMEM;  in vdo_allocate_memory()