The patch titled
Subject: zram: factor out ZRAM_SAME write
has been added to the -mm mm-unstable branch. Its filename is
zram-factor-out-zram_same-write.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-factor-out-zram_same-write.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Subject: zram: factor out ZRAM_SAME write
Date: Tue, 10 Dec 2024 19:53:58 +0900
Handling of ZRAM_SAME now uses a goto to the final stages of
zram_write_page() plus it introduces a branch and flags variable, which is
not making the code any simpler. In reality, we can handle ZRAM_SAME
immediately when we detect such pages and remove a goto and a branch.
Factor out ZRAM_SAME handling into a separate routine to simplify
zram_write_page().
Link: https://lkml.kernel.org/r/20241210105420.1888790-5-senozhatsky@xxxxxxxxxxxx
Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 37 ++++++++++++++++++--------------
1 file changed, 21 insertions(+), 16 deletions(-)
--- a/drivers/block/zram/zram_drv.c~zram-factor-out-zram_same-write
+++ a/drivers/block/zram/zram_drv.c
@@ -1626,6 +1626,20 @@ static int zram_bvec_read(struct zram *z
return zram_read_page(zram, bvec->bv_page, index, bio);
}
+static int write_same_filled_page(struct zram *zram, unsigned long fill,
+ u32 index)
+{
+ zram_slot_lock(zram, index);
+ zram_set_flag(zram, index, ZRAM_SAME);
+ zram_set_handle(zram, index, fill);
+ zram_slot_unlock(zram, index);
+
+ atomic64_inc(&zram->stats.same_pages);
+ atomic64_inc(&zram->stats.pages_stored);
+
+ return 0;
+}
+
static int zram_write_page(struct zram *zram, struct page *page, u32 index)
{
int ret = 0;
@@ -1636,7 +1650,7 @@ static int zram_write_page(struct zram *
void *src, *dst, *mem;
struct zcomp_strm *zstrm;
unsigned long element = 0;
- enum zram_pageflags flags = 0;
+ bool same_filled;
/* First, free memory allocated to this slot (if any) */
zram_slot_lock(zram, index);
@@ -1644,14 +1658,10 @@ static int zram_write_page(struct zram *
zram_slot_unlock(zram, index);
mem = kmap_local_page(page);
- if (page_same_filled(mem, &element)) {
- kunmap_local(mem);
- /* Free memory associated with this sector now. */
- flags = ZRAM_SAME;
- atomic64_inc(&zram->stats.same_pages);
- goto out;
- }
+ same_filled = page_same_filled(mem, &element);
kunmap_local(mem);
+ if (same_filled)
+ return write_same_filled_page(zram, element, index);
compress_again:
zstrm = zcomp_stream_get(zram->comps[ZRAM_PRIMARY_COMP]);
@@ -1737,7 +1747,7 @@ compress_again:
zcomp_stream_put(zram->comps[ZRAM_PRIMARY_COMP]);
zs_unmap_object(zram->mem_pool, handle);
atomic64_add(comp_len, &zram->stats.compr_data_size);
-out:
+
zram_slot_lock(zram, index);
if (comp_len == PAGE_SIZE) {
zram_set_flag(zram, index, ZRAM_HUGE);
@@ -1745,13 +1755,8 @@ out:
atomic64_inc(&zram->stats.huge_pages_since);
}
- if (flags) {
- zram_set_flag(zram, index, flags);
- zram_set_handle(zram, index, element);
- } else {
- zram_set_handle(zram, index, handle);
- zram_set_obj_size(zram, index, comp_len);
- }
+ zram_set_handle(zram, index, handle);
+ zram_set_obj_size(zram, index, comp_len);
zram_slot_unlock(zram, index);
/* Update stats */
_
Patches currently in -mm which might be from senozhatsky@xxxxxxxxxxxx are
zram-panic-when-use-ext4-over-zram-fix.patch
zram-cond_resched-in-writeback-loop.patch
zram-free-slot-memory-early-during-write.patch
zram-remove-entry-element-member.patch
zram-factor-out-zram_same-write.patch
zram-factor-out-zram_huge-write.patch
zram-factor-out-different-page-types-read.patch
