Subject: + mm-remove-compressed-copy-from-zram-in-memory-fix-2-fix.patch added to -mm tree
To: akpm@xxxxxxxxxxxxxxxxxxxx,artem.savkov@xxxxxxxxx,dan.magenheimer@xxxxxxxxxx,hughd@xxxxxxxxxx,konrad@xxxxxxxxxx,minchan@xxxxxxxxxx,ngupta@xxxxxxxxxx,shli@xxxxxxxxxx,sjenning@xxxxxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Fri, 07 Jun 2013 13:43:34 -0700
The patch titled
Subject: mm-remove-compressed-copy-from-zram-in-memory-fix-2-fix
has been added to the -mm tree. Its filename is
mm-remove-compressed-copy-from-zram-in-memory-fix-2-fix.patch
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------------------------------------------------------
From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Subject: mm-remove-compressed-copy-from-zram-in-memory-fix-2-fix
invert unlikely() test, augment comment, 80-col cleanup
Cc: Artem Savkov <artem.savkov@xxxxxxxxx>
Cc: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Cc: Seth Jennings <sjenning@xxxxxxxxxxxxxxxxxx>
Cc: Shaohua Li <shli@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_io.c | 83 +++++++++++++++++++++++++------------------------
1 file changed, 43 insertions(+), 40 deletions(-)
diff -puN mm/page_io.c~mm-remove-compressed-copy-from-zram-in-memory-fix-2-fix mm/page_io.c
--- a/mm/page_io.c~mm-remove-compressed-copy-from-zram-in-memory-fix-2-fix
+++ a/mm/page_io.c
@@ -81,51 +81,54 @@ void end_swap_bio_read(struct bio *bio,
imajor(bio->bi_bdev->bd_inode),
iminor(bio->bi_bdev->bd_inode),
(unsigned long long)bio->bi_sector);
- } else {
- SetPageUptodate(page);
+ goto out;
+ }
+
+ SetPageUptodate(page);
+
+ /*
+ * There is no guarantee that the page is in swap cache - the software
+ * suspend code (at least) uses end_swap_bio_read() against a non-
+ * swapcache page. So we must check PG_swapcache before proceeding with
+ * this optimization.
+ */
+ if (likely(PageSwapCache(page))) {
+ struct swap_info_struct *sis;
+
+ sis = page_swap_info(page);
+ if (sis->flags & SWP_BLKDEV) {
+ /*
+ * The swap subsystem performs lazy swap slot freeing,
+ * expecting that the page will be swapped out again.
+ * So we can avoid an unnecessary write if the page
+ * isn't redirtied.
+ * This is good for real swap storage because we can
+ * reduce unnecessary I/O and enhance wear-leveling
+ * if an SSD is used as the as swap device.
+ * But if in-memory swap device (eg zram) is used,
+ * this causes a duplicated copy between uncompressed
+ * data in VM-owned memory and compressed data in
+ * zram-owned memory. So let's free zram-owned memory
+ * and make the VM-owned decompressed page *dirty*,
+ * so the page should be swapped out somewhere again if
+ * we again wish to reclaim it.
+ */
+ struct gendisk *disk = sis->bdev->bd_disk;
+ if (disk->fops->swap_slot_free_notify) {
+ swp_entry_t entry;
+ unsigned long offset;
+
+ entry.val = page_private(page);
+ offset = swp_offset(entry);
- /*
- * There is no guarantee that the page is in swap cache, so
- * we need to check PG_swapcache before proceeding with this
- * optimization.
- */
- if (unlikely(PageSwapCache(page))) {
- struct swap_info_struct *sis;
-
- sis = page_swap_info(page);
- if (sis->flags & SWP_BLKDEV) {
- /*
- * The swap subsystem performs lazy swap slot freeing,
- * expecting that the page will be swapped out again.
- * So we can avoid an unnecessary write if the page
- * isn't redirtied.
- * This is good for real swap storage because we can
- * reduce unnecessary I/O and enhance wear-leveling
- * if an SSD is used as the as swap device.
- * But if in-memory swap device (eg zram) is used,
- * this causes a duplicated copy between uncompressed
- * data in VM-owned memory and compressed data in
- * zram-owned memory. So let's free zram-owned memory
- * and make the VM-owned decompressed page *dirty*,
- * so the page should be swapped out somewhere again if
- * we again wish to reclaim it.
- */
- struct gendisk *disk = sis->bdev->bd_disk;
- if (disk->fops->swap_slot_free_notify) {
- swp_entry_t entry;
- unsigned long offset;
-
- entry.val = page_private(page);
- offset = swp_offset(entry);
-
- SetPageDirty(page);
- disk->fops->swap_slot_free_notify(sis->bdev,
- offset);
- }
+ SetPageDirty(page);
+ disk->fops->swap_slot_free_notify(sis->bdev,
+ offset);
}
}
}
+out:
unlock_page(page);
bio_put(bio);
}
_
Patches currently in -mm which might be from akpm@xxxxxxxxxxxxxxxxxxxx are
linux-next.patch
arch-alpha-kernel-systblss-remove-debug-check.patch
i-need-old-gcc.patch
kmsg-honor-dmesg_restrict-sysctl-on-dev-kmsg-fix.patch
drivers-rtc-rtc-cmosc-fix-accidentally-enabling-rtc-channel-fix.patch
drivers-base-cpuc-fix-maxcpus-boot-option-fix.patch
sound-soc-codecs-si476xc-dont-use-0bnnn.patch
drivers-iommu-msm_iommu_devc-fix-leak-and-clean-up-error-paths-fix.patch
posix-timers-correctly-get-dying-task-time-sample-in-posix_cpu_timer_schedule.patch
mm.patch
clear_refs-sanitize-accepted-commands-declaration.patch
mm-remove-compressed-copy-from-zram-in-memory-fix.patch
mm-remove-compressed-copy-from-zram-in-memory-fix-2-fix.patch
memory_hotplug-use-pgdat_resize_lock-in-__offline_pages-fix.patch
include-linux-mmh-add-page_aligned-helper.patch
vmcore-allocate-buffer-for-elf-headers-on-page-size-alignment-fix.patch
vmalloc-introduce-remap_vmalloc_range_partial-fix.patch
vmcore-allocate-elf-note-segment-in-the-2nd-kernel-vmalloc-memory-fix.patch
vmcore-allow-user-process-to-remap-elf-note-segment-buffer-fix.patch
vmcore-support-mmap-on-proc-vmcore-fix.patch
mm-remove-lru-parameter-from-__lru_cache_add-and-lru_cache_add_lru.patch
mm-tune-vm_committed_as-percpu_counter-batching-size-fix.patch
swap-discard-while-swapping-only-if-swap_flag_discard_pages-fix.patch
mm-correctly-update-zone-managed_pages-fix.patch
shrinker-convert-superblock-shrinkers-to-new-api-fix.patch
xfs-convert-buftarg-lru-to-generic-code-fix.patch
xfs-convert-dquot-cache-lru-to-list_lru-fix.patch
fs-convert-fs-shrinkers-to-new-scan-count-api-fix.patch
drivers-convert-shrinkers-to-new-count-scan-api-fix.patch
drivers-convert-shrinkers-to-new-count-scan-api-fix-2.patch
shrinker-convert-remaining-shrinkers-to-count-scan-api-fix.patch
hugepage-convert-huge-zero-page-shrinker-to-new-shrinker-api-fix.patch
include-linux-mmzoneh-cleanups.patch
include-linux-mmzoneh-cleanups-fix.patch
drop_caches-add-some-documentation-and-info-messsge.patch
clean-up-scary-strncpydst-src-strlensrc-uses-fix.patch
dump_stack-serialize-the-output-from-dump_stack-fix.patch
panic-add-cpu-pid-to-warn_slowpath_common-in-warning-printks-fix.patch
rbtree-remove-unneeded-include-fix.patch
checkpatch-warn-when-using-gccs-binary-constant-extension.patch
binfmt_elfc-use-get_random_int-to-fix-entropy-depleting.patch
fat-additions-to-support-fat_fallocate-fix.patch
ptrace-add-ability-to-get-set-signal-blocked-mask-fix.patch
dev-oldmem-remove-the-interface-fix.patch
idr-print-a-stack-dump-after-ida_remove-warning-fix.patch
shm-fix-null-pointer-deref-when-userspace-specifies-invalid-hugepage-size-fix.patch
partitions-add-aix-lvm-partition-support-files-checkpatch-fixes.patch
drivers-w1-slaves-w1_ds2408c-add-magic-sequence-to-disable-p0-test-mode-fix.patch
lib-add-lz4-compressor-module-fix.patch
crypto-add-lz4-cryptographic-api-fix.patch
debugging-keep-track-of-page-owners-fix-2-fix.patch
debugging-keep-track-of-page-owners-fix-2-fix-fix-fix.patch
journal_add_journal_head-debug.patch
kernel-forkc-export-kernel_thread-to-modules.patch
mutex-subsystem-synchro-test-module.patch
slab-leaks3-default-y.patch
put_bh-debug.patch
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