From 17fa2f161897635c6f6216d5368919b254832f7d Mon Sep 17 00:00:00 2001 From: nvt-se Date: Wed, 29 Apr 2009 13:15:59 +0000 Subject: [PATCH] make sure that page isolation is called after erasing a sector in reluctant GC. simplified the GC logic a bit. --- core/cfs/cfs-coffee.c | 76 ++++++++++++++++++++++++------------------- 1 file changed, 43 insertions(+), 33 deletions(-) diff --git a/core/cfs/cfs-coffee.c b/core/cfs/cfs-coffee.c index dfade506e..0f408e63c 100644 --- a/core/cfs/cfs-coffee.c +++ b/core/cfs/cfs-coffee.c @@ -183,8 +183,9 @@ absolute_offset(coffee_page_t page, cfs_offset_t offset) return page * COFFEE_PAGE_SIZE + sizeof(struct file_header) + offset; } /*---------------------------------------------------------------------------*/ -static void -get_sector_status(uint16_t sector, struct sector_stats *stats) { +static coffee_page_t +get_sector_status(uint16_t sector, struct sector_stats *stats) +{ static coffee_page_t skip_pages; static char last_pages_are_active; struct file_header hdr; @@ -197,36 +198,15 @@ get_sector_status(uint16_t sector, struct sector_stats *stats) { if(sector == 0) { skip_pages = 0; last_pages_are_active = 0; - } else if(skip_pages > COFFEE_PAGES_PER_SECTOR) { - skip_pages -= COFFEE_PAGES_PER_SECTOR; - if(last_pages_are_active) { - stats->active = COFFEE_PAGES_PER_SECTOR; - stats->obsolete = 0; - } else { - stats->active = 0; - stats->obsolete = COFFEE_PAGES_PER_SECTOR; - } - stats->free = 0; - return; } - sector_start = sector * COFFEE_SECTOR_SIZE / COFFEE_PAGE_SIZE; - sector_end = sector_start + COFFEE_SECTOR_SIZE / COFFEE_PAGE_SIZE; + sector_start = sector * COFFEE_PAGES_PER_SECTOR; + sector_end = sector_start + COFFEE_PAGES_PER_SECTOR; if(last_pages_are_active) { - active = skip_pages; + active = skip_pages & (COFFEE_PAGES_PER_SECTOR - 1); } else { - obsolete = skip_pages; - - /* Split an obsolete file starting in the previous sector and mark - the following pages as isolated. */ - memset(&hdr, 0, sizeof(hdr)); - hdr.flags = HDR_FLAG_ALLOCATED | HDR_FLAG_ISOLATED; - for(page = 0; page < skip_pages; page++) { - write_header(&hdr, sector_start + page); - } - PRINTF("Coffee: Isolated %u pages starting in sector %d\n", - (unsigned)skip_pages, (int)sector); + obsolete = skip_pages & (COFFEE_PAGES_PER_SECTOR - 1); } for(page = sector_start + skip_pages; page < sector_end;) { @@ -243,7 +223,7 @@ get_sector_status(uint16_t sector, struct sector_stats *stats) { page += hdr.max_pages; obsolete += hdr.max_pages; } else { - free = COFFEE_PAGES_PER_SECTOR - active - obsolete; + free = sector_end - page; break; } } @@ -260,6 +240,28 @@ get_sector_status(uint16_t sector, struct sector_stats *stats) { stats->active = active; stats->obsolete = obsolete; stats->free = free; + + return last_pages_are_active ? 0 : skip_pages; +} +/*---------------------------------------------------------------------------*/ +static void +isolate_pages(coffee_page_t start, coffee_page_t skip_pages) +{ + struct file_header hdr; + coffee_page_t page; + + /* Split an obsolete file starting in the previous sector and mark + the following pages as isolated. */ + memset(&hdr, 0, sizeof(hdr)); + hdr.flags = HDR_FLAG_ALLOCATED | HDR_FLAG_ISOLATED; + + /* Isolation starts from the next sector. */ + for(page = 0; page < skip_pages; page++) { + write_header(&hdr, start + page); + } + PRINTF("Coffee: Isolated %u pages starting in sector %d\n", + (unsigned)skip_pages, (int)start / COFFEE_PAGES_PER_SECTOR); + } /*---------------------------------------------------------------------------*/ static void @@ -267,7 +269,7 @@ collect_garbage(int mode) { uint16_t sector; struct sector_stats stats; - coffee_page_t first_page; + coffee_page_t first_page, skip_pages; watchdog_stop(); @@ -278,20 +280,28 @@ collect_garbage(int mode) * erasable if there are only free or obsolete pages in it. */ for(sector = 0; sector < COFFEE_SECTOR_COUNT; sector++) { - get_sector_status(sector, &stats); + skip_pages = get_sector_status(sector, &stats); PRINTF("Coffee: Sector %u has %u active, %u free, and %u obsolete pages.\n", sector, (unsigned)stats.active, (unsigned)stats.free, (unsigned)stats.obsolete); + if(stats.active > 0) { continue; } + if((mode == GC_RELUCTANT && stats.free == 0) || - (mode == GC_GREEDY && stats.obsolete > 0)) { - COFFEE_ERASE(sector); - PRINTF("Coffee: Erased sector %d!\n", sector); + (mode == GC_GREEDY && stats.obsolete > 0)) { first_page = sector * COFFEE_PAGES_PER_SECTOR; if(first_page < *next_free) { *next_free = first_page; } + + if(skip_pages > 0) { + isolate_pages(first_page + COFFEE_PAGES_PER_SECTOR, skip_pages); + } + + COFFEE_ERASE(sector); + PRINTF("Coffee: Erased sector %d!\n", sector); + if(mode == GC_RELUCTANT) { break; }