From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaegeuk Kim Subject: Re: [f2fs-dev] [PATCH] f2fs: change the method of calculating the number summary blocks Date: Mon, 28 Oct 2013 19:34:36 +0900 Message-ID: <1382956476.992.94.camel@kjgkr> References: <21040538.71861382950468176.JavaMail.weblogic@epv6ml09> Reply-To: jaegeuk.kim@samsung.com Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-reply-to: <21040538.71861382950468176.JavaMail.weblogic@epv6ml09> Sender: linux-fsdevel-owner@vger.kernel.org To: fanofcode.li@samsung.com Cc: "linux-fsdevel@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-f2fs-devel@lists.sourceforge.net" List-Id: linux-f2fs-devel.lists.sourceforge.net Hi, 2013-10-28 (=EC=9B=94), 08:54 +0000, Fan Li: > "There is a HTML error in the previous email, so I send this one.If y= ou already received this before, please ignore it.Sorry for the inconve= nience" >=20 > This patch change the method of calculating the number of summary blo= cks in function npages_for_summary_flush. > npages_for_summary_flush uses (SUMMARY_SIZE + 1) as the size of a f2f= s_summary while the actual size is just SUMMARY_SIZE. > As a result, occasionally the return value of npages_for_summary_flus= h will be bigger than the actual number by one, and the checkpoint won'= t be written contiguously into disk. > Besides, struct f2fs_summary can't be split to two pages, so it could= take more space than the sum of its size, the current version seems no= t to take it into account. >=20 Again. Please write a description not to exceed 80 columns. > Signed-off-by: Fan Li > --- > fs/f2fs/segment.c | 14 ++++++-------- > 1 file changed, 6 insertions(+), 8 deletions(-) >=20 > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 487af61..ba2= 930f 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -279,9 +279,8 @@ static void __add_sum_entry(struct f2fs_sb_info *= sbi, int type, > */ > int npages_for_summary_flush(struct f2fs_sb_info *sbi) { > - int total_size_bytes =3D 0; > int valid_sum_count =3D 0; > - int i, sum_space; > + int i, sum_in_page; > =20 > for (i =3D CURSEG_HOT_DATA; i <=3D CURSEG_COLD_DATA; i++) { > if (sbi->ckpt->alloc_type[i] =3D=3D SSR) > @@ -290,13 +289,12 @@ int npages_for_summary_flush(struct f2fs_sb_inf= o *sbi) > valid_sum_count +=3D curseg_blkoff(sbi, i); > } > =20 > - total_size_bytes =3D valid_sum_count * (SUMMARY_SIZE + 1) > - + sizeof(struct nat_journal) + 2 > - + sizeof(struct sit_journal) + 2; > - sum_space =3D PAGE_CACHE_SIZE - SUM_FOOTER_SIZE; > - if (total_size_bytes < sum_space) > + sum_in_page =3D (PAGE_CACHE_SIZE - 2*SUM_JOURNAL_SIZE - SUM_FOOTER_= SIZE)/ sum_in_page =3D (PAGE_CACHE_SIZE - 2 * SUM_JOURNAL_SIZE - SUM_FOOTER_SIZE) / SUMMARY_SIZE; Coding style. > + SUMMARY_SIZE; > + if (valid_sum_count <=3D sum_in_page) > return 1; > - else if (total_size_bytes < 2 * sum_space) > + else if (valid_sum_count-sum_in_page <=3D > + (PAGE_CACHE_SIZE-SUM_FOOTER_SIZE)/SUMMARY_SIZE) ditto. > return 2; > return 3; > } > -- > 1.7.9.5 --=20 Jaegeuk Kim Samsung -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html