* Re: + zsmalloc-do-not-remap-dst-page-while-prepare-next-src-page.patch added to -mm tree
[not found] <5511d133.CLvN99GLSL/edQEW%akpm@linux-foundation.org>
@ 2015-03-25 5:42 ` Sergey Senozhatsky
2015-03-25 6:49 ` Stephen Rothwell
0 siblings, 1 reply; 2+ messages in thread
From: Sergey Senozhatsky @ 2015-03-25 5:42 UTC (permalink / raw)
To: Stephen Rothwell
Cc: akpm, sergey.senozhatsky, minchan, ngupta, mm-commits,
linux-kernel, linux-next, Heesub Shin
On (03/24/15 14:03), akpm@linux-foundation.org wrote:
> The patch titled
> Subject: zsmalloc: do not remap dst page while prepare next src page
> has been added to the -mm tree. Its filename is
> zsmalloc-do-not-remap-dst-page-while-prepare-next-src-page.patch
>
> This patch should soon appear at
> http://ozlabs.org/~akpm/mmots/broken-out/zsmalloc-do-not-remap-dst-page-while-prepare-next-src-page.patch
> and later at
> http://ozlabs.org/~akpm/mmotm/broken-out/zsmalloc-do-not-remap-dst-page-while-prepare-next-src-page.patch
>
Hello Stephen,
Heesub Shin has reported that this patch causes BUG_ON on ARM
(with CONFIG_DEBUG_HIGHMEM enabled). Could you please revert
it in linux-next 20150325?
-ss
> ------------------------------------------------------
> From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Subject: zsmalloc: do not remap dst page while prepare next src page
>
> The object may belong to different pages. zs_object_copy() handles this
> case and maps a new source page (get_next_page() and kmap_atomic()) when
> object crosses boundaries of the current source page. But it also
> performs unnecessary kunmap/kmap_atomic of the destination page (it
> remains unchanged), which can be avoided.
>
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Cc: Minchan Kim <minchan@kernel.org>
> Cc: Nitin Gupta <ngupta@vflare.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
> mm/zsmalloc.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff -puN mm/zsmalloc.c~zsmalloc-do-not-remap-dst-page-while-prepare-next-src-page mm/zsmalloc.c
> --- a/mm/zsmalloc.c~zsmalloc-do-not-remap-dst-page-while-prepare-next-src-page
> +++ a/mm/zsmalloc.c
> @@ -1538,12 +1538,10 @@ static void zs_object_copy(unsigned long
> break;
>
> if (s_off + size >= PAGE_SIZE) {
> - kunmap_atomic(d_addr);
> kunmap_atomic(s_addr);
> s_page = get_next_page(s_page);
> BUG_ON(!s_page);
> s_addr = kmap_atomic(s_page);
> - d_addr = kmap_atomic(d_page);
> s_size = class->size - written;
> s_off = 0;
> } else {
> _
>
> Patches currently in -mm which might be from sergey.senozhatsky@gmail.com are
>
> zram-cosmetic-zram_attr_ro-code-formatting-tweak.patch
> zram-use-idr-instead-of-zram_devices-array.patch
> zram-factor-out-device-reset-from-reset_store.patch
> zram-reorganize-code-layout.patch
> zram-add-dynamic-device-add-remove-functionality.patch
> zram-add-dynamic-device-add-remove-functionality-fix.patch
> zram-remove-max_num_devices-limitation.patch
> zram-report-every-added-and-removed-device.patch
> zram-trivial-correct-flag-operations-comment.patch
> zram-return-zram-device_id-value-from-zram_add.patch
> zram-introduce-automatic-device_id-generation.patch
> zram-introduce-automatic-device_id-generation-fix.patch
> zram-do-not-let-user-enforce-new-device-dev_id.patch
> zsmalloc-decouple-handle-and-object.patch
> zsmalloc-factor-out-obj_.patch
> zsmalloc-support-compaction.patch
> zsmalloc-adjust-zs_almost_full.patch
> zram-support-compaction.patch
> zsmalloc-record-handle-in-page-private-for-huge-object.patch
> zsmalloc-add-fullness-into-stat.patch
> zsmalloc-zsmalloc-documentation.patch
> zram-remove-num_migrated-device-attr.patch
> zram-move-compact_store-to-sysfs-functions-area.patch
> zram-use-generic-start-end-io-accounting.patch
> zram-describe-device-attrs-in-documentation.patch
> zram-export-new-io_stat-sysfs-attrs.patch
> zram-export-new-mm_stat-sysfs-attrs.patch
> zram-deprecate-zram-attrs-sysfs-nodes.patch
> zsmalloc-remove-synchronize_rcu-from-zs_compact.patch
> zsmalloc-remove-extra-cond_resched-in-__zs_compact.patch
> zsmalloc-do-not-remap-dst-page-while-prepare-next-src-page.patch
> zsmalloc-micro-optimize-zs_object_copy.patch
> cpumask-dont-perform-while-loop-in-cpumask_next_and.patch
> lib-lz4-pull-out-constant-tables.patch
>
> --
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