On 2019/8/9 23:39, Jaegeuk Kim wrote:
> On 08/10, Ju Hyung Park wrote:
>> Hi Jaegeuk,
>>
>> Just out of curiosity, what's the point of this?
>>
>> I thought flash chips skip erasing blocks if it's already erased to
>> preserve P/E cycles as much as possible.
>> All Android devices I had(various versions of eMMC and UFS) ran full range
>> block-level discards pretty fast too.
>
> Unfortunately, some of them are giving long delays on a bunch of unmap
> commands
> resulting in user janky issue.
Agreed, the performance completely depends on FTL implementation, some of them
perform very bad...
Thanks,
>
>>
>> Thanks.
>>
>> 2019년 8월 10일 (토) 오전 12:13, Jaegeuk Kim <jaeg...@kernel.org>님이 작성:
>>
>>> We actually don't need to issue trim on entire disk by checking first
>>> blocks having zeros.
>>>
>>> Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
>>> ---
>>> v2 from v1:
>>> - clean up
>>>
>>> mkfs/f2fs_format_utils.c | 53 ++++++++++++++++++++++++++++++++++++++--
>>> 1 file changed, 51 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/mkfs/f2fs_format_utils.c b/mkfs/f2fs_format_utils.c
>>> index 8bf128c..f2d55ad 100644
>>> --- a/mkfs/f2fs_format_utils.c
>>> +++ b/mkfs/f2fs_format_utils.c
>>> @@ -25,6 +25,7 @@
>>> #include <stdio.h>
>>> #include <unistd.h>
>>> #include <stdlib.h>
>>> +#include <stdbool.h>
>>> #ifndef ANDROID_WINDOWS_HOST
>>> #include <sys/ioctl.h>
>>> #endif
>>> @@ -110,13 +111,61 @@ static int trim_device(int i)
>>> return 0;
>>> }
>>>
>>> +static bool is_wiped_device(int i)
>>> +{
>>> +#ifdef WITH_ANDROID
>>> + struct device_info *dev = c.devices + i;
>>> + int fd = dev->fd;
>>> + char *buf, *zero_buf;
>>> + bool wiped = true;
>>> + int nblocks = 4096; /* 16MB size */
>>> + int j;
>>> +
>>> + buf = malloc(F2FS_BLKSIZE);
>>> + if (buf == NULL) {
>>> + MSG(1, "\tError: Malloc Failed for buf!!!\n");
>>> + return false;
>>> + }
>>> + zero_buf = calloc(1, F2FS_BLKSIZE);
>>> + if (zero_buf == NULL) {
>>> + MSG(1, "\tError: Calloc Failed for zero buf!!!\n");
>>> + free(buf);
>>> + return false;
>>> + }
>>> +
>>> + if (lseek(fd, 0, SEEK_SET) < 0) {
>>> + free(zero_buf);
>>> + free(buf);
>>> + return false;
>>> + }
>>> +
>>> + /* check first n blocks */
>>> + for (j = 0; j < nblocks; j++) {
>>> + if (read(fd, buf, F2FS_BLKSIZE) != F2FS_BLKSIZE ||
>>> + memcmp(buf, zero_buf, F2FS_BLKSIZE)) {
>>> + wiped = false;
>>> + break;
>>> + }
>>> + }
>>> + free(zero_buf);
>>> + free(buf);
>>> +
>>> + if (wiped)
>>> + MSG(0, "Info: Found all zeros in first %d blocks\n",
>>> nblocks);
>>> + return wiped;
>>> +#else
>>> + return false;
>>> +#endif
>>> +}
>>> +
>>> int f2fs_trim_devices(void)
>>> {
>>> int i;
>>>
>>> - for (i = 0; i < c.ndevs; i++)
>>> - if (trim_device(i))
>>> + for (i = 0; i < c.ndevs; i++) {
>>> + if (!is_wiped_device(i) && trim_device(i))
>>> return -1;
>>> + }
>>> c.trimmed = 1;
>>> return 0;
>>> }
>>> --
>>> 2.19.0.605.g01d371f741-goog
>>>
>>>
>>>
>>> _______________________________________________
>>> Linux-f2fs-devel mailing list
>>> Linux-f2fs-devel@lists.sourceforge.net
>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
>>>
>
>
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