FROMLIST: mm: fs: Invalidate BH LRU during page migration

Pages containing buffer_heads that are in one of the per-CPU
buffer_head LRU caches will be pinned and thus cannot be migrated.
This can prevent CMA allocations from succeeding, which are often used
on platforms with co-processors (such as a DSP) that can only use
physically contiguous memory. It can also prevent memory
hot-unplugging from succeeding, which involves migrating at least
MIN_MEMORY_BLOCK_SIZE bytes of memory, which ranges from 8 MiB to 1
GiB based on the architecture in use.

Correspondingly, invalidate the BH LRU caches before a migration
starts and stop any buffer_head from being cached in the LRU caches,
until migration has finished.

Bug: 180018981
Link: https://lore.kernel.org/linux-mm/20210319175127.886124-3-minchan@kernel.org/
Tested-by: Oliver Sang <oliver.sang@intel.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Chris Goldsworthy <cgoldswo@codeaurora.org>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Minchan Kim <minchan@google.com>
Change-Id: Idb8279cb561812f5f1b43ddbb742c1808700754e
This commit is contained in:
Minchan Kim
2021-03-19 12:49:41 -07:00
committed by Suren Baghdasaryan
parent c6bc1396ce
commit a0a0b3f42e
3 changed files with 38 additions and 7 deletions

View File

@@ -194,6 +194,8 @@ void __breadahead_gfp(struct block_device *, sector_t block, unsigned int size,
struct buffer_head *__bread_gfp(struct block_device *,
sector_t block, unsigned size, gfp_t gfp);
void invalidate_bh_lrus(void);
void invalidate_bh_lrus_cpu(int cpu);
bool has_bh_in_lru(int cpu, void *dummy);
struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
void free_buffer_head(struct buffer_head * bh);
void unlock_buffer(struct buffer_head *bh);
@@ -406,6 +408,8 @@ static inline int inode_has_buffers(struct inode *inode) { return 0; }
static inline void invalidate_inode_buffers(struct inode *inode) {}
static inline int remove_inode_buffers(struct inode *inode) { return 1; }
static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; }
static inline void invalidate_bh_lrus_cpu(int cpu) {}
static inline bool has_bh_in_lru(int cpu, void *dummy) { return 0; }
#define buffer_heads_over_limit 0
#endif /* CONFIG_BLOCK */