The patch titled
Subject: zram: cond_resched() in writeback loop
has been added to the -mm mm-unstable branch. Its filename is
zram-cond_resched-in-writeback-loop.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-cond_resched-in-writeback-loop.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: cond_resched() in writeback loop
Date: Tue, 10 Dec 2024 19:53:55 +0900
Patch series "zram: split page type read/write handling".
This is a subset of [1] series which contains only fixes and improvements
(no new features, as ZRAM_HUGE split is still under consideration).
The motivation for factoring out is that zram_write_page() gets more and
more complex all the time, because it tries to handle too many scenarios:
ZRAM_SAME store, ZRAM_HUGE store, compress page store with zs_malloc
allocation slowpath and conditional recompression, etc. Factor those out
and make things easier to handle.
Addition of cond_resched() is simply a fix, I can trigger watchdog from
zram writeback(). And early slot free is just a reasonable thing to do.
[1] https://lore.kernel.org/linux-kernel/20241119072057.3440039-1-senozhatsky@xxxxxxxxxxxx
This patch (of 6):
Writeback loop can run for quite a while (depending on wb device
performance, compression algorithm and the number of entries we
writeback), so we need to do cond_resched() there, similarly to what we do
in recompress loop.
Link: https://lkml.kernel.org/r/20241210105420.1888790-1-senozhatsky@xxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20241210105420.1888790-2-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 | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/block/zram/zram_drv.c~zram-cond_resched-in-writeback-loop
+++ a/drivers/block/zram/zram_drv.c
@@ -889,6 +889,8 @@ static ssize_t writeback_store(struct de
next:
zram_slot_unlock(zram, index);
release_pp_slot(zram, pps);
+
+ cond_resched();
}
if (blk_idx)
_
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
