Commit 89e85bce authored by Minchan Kim's avatar Minchan Kim Committed by Linus Torvalds

zram: mark incompressible page as ZRAM_HUGE

Mark incompressible pages so that we could investigate who is the owner
of the incompressible pages once the page is swapped out via using
upcoming zram memory tracker feature.

With it, we could prevent such pages to be swapped out by using mlock.
Otherwise we might remove them.

This patch exposes new stat for huge pages via mm_stat.

Link: http://lkml.kernel.org/r/20180416090946.63057-3-minchan@kernel.orgSigned-off-by: default avatarMinchan Kim <minchan@kernel.org>
Reviewed-by: default avatarSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c4d6c4cc
......@@ -218,6 +218,7 @@ line of text and contains the following stats separated by whitespace:
same_pages the number of same element filled pages written to this disk.
No memory is allocated for such pages.
pages_compacted the number of pages freed during compaction
huge_pages the number of incompressible pages
9) Deactivate:
swapoff /dev/zram0
......
......@@ -729,14 +729,15 @@ static ssize_t mm_stat_show(struct device *dev,
max_used = atomic_long_read(&zram->stats.max_used_pages);
ret = scnprintf(buf, PAGE_SIZE,
"%8llu %8llu %8llu %8lu %8ld %8llu %8lu\n",
"%8llu %8llu %8llu %8lu %8ld %8llu %8lu %8llu\n",
orig_size << PAGE_SHIFT,
(u64)atomic64_read(&zram->stats.compr_data_size),
mem_used << PAGE_SHIFT,
zram->limit_pages << PAGE_SHIFT,
max_used << PAGE_SHIFT,
(u64)atomic64_read(&zram->stats.same_pages),
pool_stats.pages_compacted);
pool_stats.pages_compacted,
(u64)atomic64_read(&zram->stats.huge_pages));
up_read(&zram->init_lock);
return ret;
......@@ -805,6 +806,11 @@ static void zram_free_page(struct zram *zram, size_t index)
{
unsigned long handle;
if (zram_test_flag(zram, index, ZRAM_HUGE)) {
zram_clear_flag(zram, index, ZRAM_HUGE);
atomic64_dec(&zram->stats.huge_pages);
}
if (zram_wb_enabled(zram) && zram_test_flag(zram, index, ZRAM_WB)) {
zram_wb_clear(zram, index);
atomic64_dec(&zram->stats.pages_stored);
......@@ -973,6 +979,7 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
}
if (unlikely(comp_len >= huge_class_size)) {
comp_len = PAGE_SIZE;
if (zram_wb_enabled(zram) && allow_wb) {
zcomp_stream_put(zram->comp);
ret = write_to_bdev(zram, bvec, index, bio, &element);
......@@ -984,7 +991,6 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
allow_wb = false;
goto compress_again;
}
comp_len = PAGE_SIZE;
}
/*
......@@ -1046,6 +1052,11 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
zram_slot_lock(zram, index);
zram_free_page(zram, index);
if (comp_len == PAGE_SIZE) {
zram_set_flag(zram, index, ZRAM_HUGE);
atomic64_inc(&zram->stats.huge_pages);
}
if (flags) {
zram_set_flag(zram, index, flags);
zram_set_element(zram, index, element);
......
......@@ -47,6 +47,7 @@ enum zram_pageflags {
ZRAM_LOCK = ZRAM_FLAG_SHIFT,
ZRAM_SAME, /* Page consists the same element */
ZRAM_WB, /* page is stored on backing_device */
ZRAM_HUGE, /* Incompressible page */
__NR_ZRAM_PAGEFLAGS,
};
......@@ -71,6 +72,7 @@ struct zram_stats {
atomic64_t invalid_io; /* non-page-aligned I/O requests */
atomic64_t notify_free; /* no. of swap slot free notifications */
atomic64_t same_pages; /* no. of same element filled pages */
atomic64_t huge_pages; /* no. of huge pages */
atomic64_t pages_stored; /* no. of pages currently stored */
atomic_long_t max_used_pages; /* no. of maximum pages stored */
atomic64_t writestall; /* no. of write slow paths */
......
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