[PATCH 04/13] blk: introduce REQ_SWAP
From: Josef Bacik <josef@toxicpanda.com>
Date: 2018-05-29 21:17:15
Also in:
linux-fsdevel, linux-mm, lkml
Subsystem:
block layer, control group - block io controller (blkio), memory management, memory management - swap, the rest · Maintainers:
Jens Axboe, Tejun Heo, Josef Bacik, Andrew Morton, Chris Li, Kairui Song, Linus Torvalds
From: Josef Bacik <redacted> Just like REQ_META, it's important to know the IO coming down is swap in order to guard against potential IO priority inversion issues with cgroups. Add REQ_SWAP and use it for all swap IO, and add it to our bio_issue_as_root_blkg helper. Signed-off-by: Josef Bacik <redacted> --- include/linux/blk-cgroup.h | 2 +- include/linux/blk_types.h | 3 ++- mm/page_io.c | 2 +- 3 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index b41292726c0f..a8f9ba8f33a4 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h@@ -254,7 +254,7 @@ static inline struct blkcg *bio_blkcg(struct bio *bio) */ static inline bool bio_issue_as_root_blkg(struct bio *bio) { - return (bio->bi_opf & REQ_META); + return (bio->bi_opf & (REQ_META | REQ_SWAP)) != 0; } /**
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index ff181df8c195..4f7ba397d37d 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h@@ -327,7 +327,7 @@ enum req_flag_bits { /* for driver use */ __REQ_DRV, - + __REQ_SWAP, /* swapping request. */ __REQ_NR_BITS, /* stops here */ };
@@ -349,6 +349,7 @@ enum req_flag_bits { #define REQ_NOUNMAP (1ULL << __REQ_NOUNMAP) #define REQ_DRV (1ULL << __REQ_DRV) +#define REQ_SWAP (1ULL << __REQ_SWAP) #define REQ_FAILFAST_MASK \ (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
diff --git a/mm/page_io.c b/mm/page_io.c
index b41cf9644585..a552cb37e220 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c@@ -338,7 +338,7 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc, ret = -ENOMEM; goto out; } - bio->bi_opf = REQ_OP_WRITE | wbc_to_write_flags(wbc); + bio->bi_opf = REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc); count_swpout_vm_event(page); set_page_writeback(page); unlock_page(page);
--
2.14.3